I've just completed my front screen wall with 4-way DIY masking.

Over the next few days, I'll post pictures of the screen, followed by diagrams and pictures of the building process. Bear with me as I do this because I'm a bit slow at getting the diagrams drawn and pictures taken and then uploaded to the internet.

Here is my front wall without the wall panels...
http://home.comcast.net/~scottj0007/theater/ScreenWall_B_1.jpg


Finished with masking at 16:9...
http://home.comcast.net/~scottj0007/theater/ScreenWall_B_2.jpg


Finished with masking at 2.35:1 ...
http://home.comcast.net/~scottj0007/theater/ScreenWall_B_3.jpg

I'm using a Panasonic AE1000 projector with a Prismasonic H-FE1500R anamorphic lens.

Here are some more pictures showing the masking.

Image size of 4:3
http://home.comcast.net/~scottj0007/theater/Masking_133.jpg


Image size of 16:9
http://home.comcast.net/~scottj0007/theater/Masking_178.jpg


Image size of 2.35:1
http://home.comcast.net/~scottj0007/theater/Masking_235.jpg


Image size of 2.40:1
(Notice that the top and bottom masking is moved in by a little bit compared to the picture above.)
http://home.comcast.net/~scottj0007/theater/Masking_240.jpg


(There is a bit of distortion in the above pictures because I am using a wide-angled lens on my camera. It is not there in real life. Also, I enhanced the photos by taking two identical images with the camera on a tripod. One is taken with the lights on and one with the lights off. I then superimposed the screen from the lights-out photo onto the lights-on photo. No other modifications were made to the images).



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UPDATE February 9, 2009 -- It is now MOTORIZED too!

- Jump to THIS POST (http://www.avsforum.com/avs-vb/showthread.php?p=15766851#post15766851) to see more information on the motorization.
- Or see a video of the motorization HERE. (http://www.youtube.com/watch?v=lyGMuy_TzkQ)
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- Scott

My masking system is probably more complicated than some of the others that have been described in this forum. I had a couple of special needs, that some of you may not have which means you can (and probably should) build a more simple solution.

My needs:
1) The masking material needed to be acoustically transparent. All of my speakers are behind an acoustically transparent SMX screen (127" wide). My speakers are moved to the very outside edges of the screen (In the very first photo in my first post, the speakers were closer together than where they are at now). When the masking moves from Cinemascope to 16:9, it covers the speakers.

2) On either side of my screen, I have doors that give access to the area behind my false wall. I wanted this access to remain clear of obstructions, therefore I could not use masking panels that slide back and forth on rails. Instead, I had to find a solution for my side masking that would fit in a space only a few inches wide.

3) Even though we talk about "constant height" I have found that I still need to make slight adjustments to the height of my screen for several reasons:
a) I have varying degrees of pin-cushion distortion with my lens set-up and I need to over-scan the image onto the masking more when I am in stretch mode than when I am in pass-through mode.
b) Any aspect ratio greater than 2.35:1 ends up being a little bit shorter in height compared to 2.35:1 unless you use the zoom feature on your projector. The exception would be if you have a scaler that will stretch in increments other than 1/3 (of course then you technically would need an anamorphic lens that would stretch in the same increment).
c) When I was building my screen and theater, I did not yet have the projector and lens. I wasn't exactly sure what height would eventually work in my room. I also wanted to future-proof my screen in case I ever get another projector or lens that has different throw characteristics.

Because of the above, I opted for four-way masking using rollers on the sides and using black GOM as the masking material.

Details will follow...

Here is a diagram of the side masking rollers and cables. This diagram is the top view, looking down on the assembly.
I will post some photos next.

http://home.comcast.net/~scottj0007/theater/MaskingSide_TopView_1.jpg

Very very nice Scott. Can't wait to see pictures of the system up close. It's a fantastic looking solution, which I'm sure many will want to try.

Here are some detail pictures of side masking rollers and cables.
Everything was purchased at Home Depot except the fabric, the aluminum pipe, and the pipe bearings.




http://home.comcast.net/~scottj0007/theater/MaskingSide_Photo_01.jpg


Patio door rollers mounted to strong-tie fittings found at Home Depot:
http://home.comcast.net/~scottj0007/theater/MaskingSide_Photo_02.jpg

Spring and turn-buckle bolt
http://home.comcast.net/~scottj0007/theater/MaskingSide_Photo_03.jpg

http://home.comcast.net/~scottj0007/theater/MaskingSide_Photo_04a.jpg
Note the back Gorilla masking tape. I had to use this because as the fabric rolls onto the pipe, the diameter gets bigger and the fabric begins to roll up faster. The cable has to roll onto the pipe at the same rate as the fabric or else it starts to bind. This is not an elegant solution, but it works. I wrapped several layers of tape where the cable starts on the pipe and then there are fewer and fewer as the cable wraps down the pipe, it was a trial and error effort that took some time to get right, but it works very smoothly now.

Here are some detail pictures of the bearing system I used for the vertical rollers. I can't stress how important it is to have the rollers operate smoothly. I had to completely scrap my first attempt because I tried to use electrical conduit pipe and PVC fittings for the vertical rollers. It was a miserable failure. This one works like a charm. I had to go to specialty suppliers to buy the aluminum pipe and the bearings.

http://home.comcast.net/~scottj0007/theater/MaskingBearing_Photo_01.jpg

http://home.comcast.net/~scottj0007/theater/MaskingBearing_Photo_02.jpg

http://home.comcast.net/~scottj0007/theater/MaskingBearing_Photo_03.jpg

That's it for the side masking. I'll post diagrams and pictures of the top and bottom horizontal masking later this week.

In case you are wondering... my masking system is not yet motorized. In all honesty it really doesn't need to be because it operates so easily and smoothly by hand. However, the COOL factor of a motorized system will probably entice me to add motors to it someday:cool:. It should be very easy to add motors to the roller bars.

As a side note... The masking probably cost me around $500 with all of the trial and error, including wasted materials and restarts. However, if you count the time I have spent, it has been ridiculously expensive. If I were starting over, I would probably look seriously at the HTIQ (http://www.htiq.com) masking system. I met Don at CEDIA and saw his product and have also exchanged a few emails with him. His motorization system is exceptional, but I don't believe he has a four-way masking system with acoustically transparent fabric at this time.

Let me know if you have any questions about my masking system so far. I will do my best to answer.

That looks amazing! Wow...

Very cool work. I was thinking of doing something very similar to this using IR motorized roller blind parts turned sideways. I am definetly going to keep track of this thread for ideas if I ever get around to building a masking system. Again great work!

Yes, very good work and well thought out design :)

I am looking forward to the top/bottom masking as I want to rig a roll down side masking system and like the idea of the rollers...

Mark

Very nice looking screen wall and a great idea. One question how do you have the material and the cables attached to the aluminum rod? Cable could prob be poked through a hole and clamped on the inside...but?

Nate

Your system is a thing of beauty and an inspiration. I wanted to do some sort of panel masking system because I like the clean look of the screen wall, but lately had been thinking it would be easier to do a motorized curtain set up. Now you have my wheels spinning.

Simply amazing, I vote for this to be the first sticky of this Sub Forum.

Very nice looking screen wall and a great idea. One question how do you have the material and the cables attached to the aluminum rod? Cable could prob be poked through a hole and clamped on the inside...but?
The GOM fabric is attached to the aluminum pipe with Gorilla tape (from Home Depot). The only trick is making sure you get the fabric on straight. The gorilla tape is amaizingly strong. I also allowed for one extra wrap of fabric around the pipe, which means the fabric is always applying pressure to the top of the tape, even when the masking is fully extended.

To attach the cable, I used a short metal screw with a washer on it. I pre-drilled a hole for the screw and then screwed it into the pipe. The end of the cable goes under the washer. It holds great, plus allows for adjustment if needed.

That's a very amazing setup...I will probably borrow one or two of your ideas when I build my masking system...I would like to see more pictures showing the relative distance between your screen, the screen frame, the moving boards covered with velvet and the removable panels that cover the whole setup. Again, congratulations, this is awesome! (any additionnal picture of your setup would be welcome...)

That's a very amazing setup...I will probably borrow one or two of your ideas when I build my masking system...I would like to see more pictures showing the relative distance between your screen, the screen frame, the moving boards covered with velvet and the removable panels that cover the whole setup. Again, congratulations, this is awesome! (any additionnal picture of your setup would be welcome...)
I'll post some more pictures later this week. (I would go take a couple pictures now for you, but the theater is in use by my daughter and four of her friends :) ). In the mean time, there is about 1/4" to 1/2" between my screen and the horizontal masking. The horizontal masking itself about 1/2" thick. Then there is only about another 1/4" of space between the horizontal masking and the vertical masking shown above. I was careful to keep everything pretty tight to the screen because I didn't want to get any shadows.

Stef,
Here is a quick and dirty diagram showing the approximate distances from my memory. I'll confirm and take some photos as well...
http://home.comcast.net/~scottj0007/theater/MaskingSide_SideView_1.jpg

Scott is a genius...

Stef,
Here is a photo. It is kind of hard to take good pictures with the black background, but hopefully this gives you a good idea of the distances.
http://home.comcast.net/~scottj0007/theater/masking_spacing.jpg

Now for the horizontal masking...

When I designed my horizontal masking, I didn't have any significant limitation for space above or below the screen so I decided to attach the masking to the back of the false wall. The concepts however can be modified if you want to use some of the ideas for a situation where you want the horizontal masking to be place in front of the screen.

I am finding that it is a little hard for me to describe my setup in words and two-dimensional diagrams, and the photos that I have tried to take are not as clear as I had hoped. (Photos of black on black are not easy).

The way I am going to try to do this is in steps. First, I need to explain how my screen is attached. I made my own screen frame out of 3/4" maple and intentionally did not put a boarder on the screen. Boarders add thickness to the screen but I wanted my masking to hug the screen as close as possible. Plus, my masking provides the boarder as seen in the pictures above.

The screen is attached to the back side of the false wall. I have two 1 X 4 pieces of board that span the distance of the screen opening. On the top board, I have an aluminum "U" channel attached to the bottom edge of the board. On the bottom board, I have an aluminum "J" channel attached to the top edge of the board. I made the "J" channel by taking a piece of "U" channel from Home Depot and simply cutting off part of the front "U" with a carbide saw blade on my table saw (be sure to wear EYE PROTECTION!). I install the screen by slipping it up into the "U" as far as it will go and the swinging the bottom of the screen into the "J", clearing the front edge of the "J". When the screen bottom hits the back of the "J", I drop it down. This setup makes it easy for me to remove the screen any time I need.

You can see the 1X4 boards and aluminum channel in the very first photo that I posted in this thread.

Here is a diagram...
http://home.comcast.net/~scottj0007/theater/Masking_Horizontal_01.jpg


I will post some photos later.

Stef,
Here is a photo. It is kind of hard to take good pictures with the black background, but hopefully this gives you a good idea of the distances.
http://home.comcast.net/~scottj0007/theater/masking_spacing.jpg


Thanks...Exactly the angle I wanted to see! :)

Horizontal Masking...

I know this diagram and the last one are pretty busy. Sorry about that but it is easier for me to explain it this way than trying to put it into words. After this I'll post some pictures...

http://home.comcast.net/~scottj0007/theater/Masking_Horizontal_02.jpg

Quick simple question (I hope). How does the side masking stay in the respective positions (1.78, 1.85, 1.33, etc.) I don't see a hook or some to keep the maskingin place. With teh rollers and the springs wouldn't it just roll back up?

The side masking simply stays where I put it. That is the beauty of the cable system. The cables put just enough tension on the vertical board to hold it perpendicular, but they do not pull it in either direction. Using about a pound of finger pressure, I just pull or push on the vertical board to slide it where I want it to go. (It will be very easy to motorize someday).

Here is my framing for my screen. It is 3/4" thick with no boarder.

http://home.comcast.net/~scottj0007/theater/masking__0000.jpg

These photos are of the upper left corner of the masking, from the front side:

with screen in place, side masking removed -
http://home.comcast.net/~scottj0007/theater/masking__0001.jpg

without screen in place, side masking removed -
http://home.comcast.net/~scottj0007/theater/masking__0002.jpg

-masking fully extended
http://home.comcast.net/~scottj0007/theater/masking__0003.jpg

These photos are of the upper left corner of the masking, from the BACK side:

with screen in place, side masking removed -
http://home.comcast.net/~scottj0007/theater/masking__0004.jpg


http://home.comcast.net/~scottj0007/theater/masking__0005.jpg

http://home.comcast.net/~scottj0007/theater/pipe_roller.jpg

These photos are of the lower left corner of the masking, from the front side:

with screen in place, side masking removed -
http://home.comcast.net/~scottj0007/theater/masking__0006.jpg

the "U" channel for the cross bar is essential. Without it, the cross-bar tends to flop forward. It also guides it within 1/4" of the face of the screen.
http://home.comcast.net/~scottj0007/theater/masking__0007.jpg

-notice in this picture that there is a zip-tie wrapped tightly around the end of the cross piece of aluminum, inside of the aluminum "U" channel. This has two purposes, first it makes it more snug, and secondly, it helps the two pieces of metal slide easily and quietly.
http://home.comcast.net/~scottj0007/theater/masking__0008.jpg

with masking fully extended -
http://home.comcast.net/~scottj0007/theater/masking__0009.jpg

This photo is of the lower left corner of the masking, from the BACK side:

http://home.comcast.net/~scottj0007/theater/masking__0010.jpg

These photos are of the lower right corner of the masking, from the front side:

- masking fully extended
- also notice that there is no hem in the GOM fabric. A hem would stop the freying of the material, but it would also double the thickness on the edges and would cause problems when it rolls onto the roller bars. Instead, I used a product called "frey check". It is basically a fabric glue that I applied to all exposed edges of the GOM. It should never frey more than what you see in these pictures.
http://home.comcast.net/~scottj0007/theater/masking__0011.jpg

http://home.comcast.net/~scottj0007/theater/masking__0012.jpg

Final photos:

http://home.comcast.net/~scottj0007/theater/masking__0013.jpg

http://home.comcast.net/~scottj0007/theater/masking__0014.jpg

And finally, just to show what it looks like with the masking fully extended to its limits.
http://home.comcast.net/~scottj0007/theater/masking__0015.jpg

Sorry for the ad-nausea detail, but it is the only way I thought I could adequately describe my setup.

As I said earlier, I hope to motorize it someday. It should be very easy to attach motors to the roller bars. The trick will be getting a controller system that allows for multiple pre-set stopping points with an IR remote.

Fantastic job.. Looks like something anyone of us can build.. or modify to fit in our theaters ..

Great job!

Thank you very much for the detailed pics... The horizontal project is what I was needing. I'm sure I'll be back with questions when I get into it but you did such a good job explaining it hopefully I won't have any. Thanks again for taking the time.

Mike

You're welcome. I think masking is a great enhancement. I hope the explanations help other AVSers consider building a system. Let me know if you have any questions.

Scott,

I have a question about the horizontal masking. Does the board sewn in the pocket ever sit in front of your mains? Or does the bar move outside the mains in 2.35 mode and inside when smaller? Is my question making sense?

Thanks,

Jeff

I have a question about the horizontal masking. Does the board sewn in the pocket ever sit in front of your mains? Or does the bar move outside the mains in 2.35 mode and inside when smaller? Is my question making sense?
Your question makes sense. If you are referring to the vertical board that is sewn into the side masking, the answer is no, it never sits in front of the speakers. I placed the speakers so they are just inside the screen when it is in 2.35 mode. When I switch to 16:9 mode, the masking material (GOM) covers the speakers, but the board is passed the speakers.

Scott,

Thanks for the reply, that is exactly what I meant. Your system is awesome. If I had the room for a false wall, I would definitely give this some serious consideration and effort. Great job!

Jeff

I also wanted to say what a fantastic job you did. Probably the best engineering solution (concept and execution) I've seen (DIY or otherwise). I also think the overall look of the entire theater is very elegant and attractive. Thanks for providing detailed descriptions and photos of your design - very generous of you.

Yes thank you very much looks great. The weight of the steel and aluminum bars counter weigh each other to keep it in position? This makes me want to tear my wall apart to start building.

Nate

Yes thank you very much looks great. The weight of the steel and aluminum bars counter weigh each other to keep it in position? Yes, exactly. Without the lower masking to act as a counter-balance, the top masking would just roll down due to the weight of the bar.

While we are talking about the bars, let me add that the bars for the lower masking gave me a lot of headaches before I got it working right. I first tried a 1/4" X 2" steel bar and did not use the side "U" channel. This didn't work at all. Steel is much heavier than aluminum and the steel would just bend in the middle out away from the screen and then fall forward.

Rather than the 1/4" aluminum, another option would have been to use a thicker material like 3/4" wood. This would have been a little more simple and cheaper, but I was a bit paranoid about keeping the masking very close to the screen. Using thicker material would have moved the side masking further away from the screen. My solution might be overkill.

If I were starting over on the masking I would probably put some more thought into trying to do the top and bottom masking more like I did my side masking. I think with a little bit of thought, one could come up with a solution where all four sides of the masking were built in the same way with the same roller bars, bearings, and cabling setup. I'm pretty sure it would be possible to come up with a system that could be surface mounted and would work for someone who does not have a false wall.

Like everyone else, I want to commend you on an excellent job, and thank you for sharing all the details.

Could you please provide an explanation of the steps you take when switching between the different aspect ratios? Do you move your lens out of the way for 16:9 and 4:3? Do you have to tell the projector to "unstretch" the image? Is any refocusing required? Thanks again.

Could you please provide an explanation of the steps you take when switching between the different aspect ratios? Do you move your lens out of the way for 16:9 and 4:3? Do you have to tell the projector to "unstretch" the image? Is any refocusing required?

I use a Prismasonic H-FE1500R anamorphic lens (http://www.prismasonic.com/english/description_hfe1500r.shtml). This lens has a "pass through" mode. I just hit a button on my remote to change from stretch mode to pass-through mode. I also hit a button on my remote to change my Panasonic AE1000 projector from "virtical stretch" to 16:9 mode. That's it. No adjustments to focus or zoom.

I also find that your masking system is really outstanding. I tried putting something like that toguether too but I gave up half way as it was too time consuming.

I have a couple of question:

You could have run your cable to link the left to the right so that a pull from one side would have moved the other side in a symetrical way. Is there any reason why you did not synchronized the side masking?

How do you proceed to adjust the masking? Do you have marks to indicate where to stop for the various aspect ratios?

You could have run your cable to link the left to the right so that a pull from one side would have moved the other side in a symmetrical way. Is there any reason why you did not synchronized the side masking? In my original plan, I did intend to put a cable between the two roller bars so that the masking was synchronized. I still may do this but just haven't yet. It will only take a couple minutes to do.

For anyone wondering how this would work, I will simply use the same vinyl aircraft cable that I used for the rest of the masking and loop it around each of the vertical rollers for the side masking. However, I will cross the cable between the rollers so that it is in a figure 8. This will cause the rollers to turn in opposite directions. (If this doesn't make sense, just try it by putting a rubber band around two pencils and then spin the pencils between your fingers to see how crossing the rubber band in a figure 8 changes the direction of the spin.) I will also put a turn-buckle bolt on the cable so I can easily adjust the tension.

How do you proceed to adjust the masking? Do you have marks to indicate where to stop for the various aspect ratios? I have a very LOW-tech method that I use :eek:. I display the picture first, and then just move the masking to the edge of the picture. If I ever motorize the system, I would like to find a motor control that has multiple pre-set stop positions. This would enable me to just push a button and have the masking move to the pre-determined stopping points.

Scott,
Absolutely amazing! Thank you so much for taking the time to document and post all of this wonderful detail. Reading through this thread has been a ton of fun and informative as well. Your posts, IMHO, are representative of the very best posts of the very best forum in the world. Kudos.
-Pete

Thank you Pete. I appreciate receiving the compliments from everyone. I have learned so much on this forum from other people. It is nice to be able to give back in a small way.

Scott;
Very impressive work. Congrats! Thanks also for your detailed descriptions. It is an excellent source for ideas and inspirations.
____
Axel

Great job, Scott. I'm going to shamelessly steal your design :)

Your "low tech" positioning method sparked a thought about motorization...
Everyone, commercial folks too, always talk about/use preset positioning to control the motors. Is there a such a thing as a light sensitive sensor that can sense the brightness of being "in the beam" of the projector? That way the system could be self positioning and not depend on preset locations.

To get a feel of what I mean, hold your hand against your screen at the black border and stick your finger just inside the edge of a projected image. See? Your finger is brighter than when it was out of the image. A sensor could detect that difference and stop the masking at that spot.

Just a thought anyways. Again, nice job, Scott!

Thanks Andy. I've read a couple of threads on other forums where people have toyed with photo sensors to sense the light and automatically position the masking to the light. The problem comes when there are dark scenes. You don't want your masking to try to reposition itself every time the screen goes dark during a movie. To get around this, people have added timers to the photo sensors so that the masking only moves when the photo sensor is dark for longer than say, 20 seconds.

This all gets WAY over my head in terms of electronics and motor control. I think I'll be happy if I can just figure out simple presets with flash memory and basic IR control.:D

You are welcome to "steal" any ideas you want. If you get started on the project, feel free to PM me if you would like and I'll be happy to discuss more detail or suggested alternatives.

Thanks for the info offer. I'm in the stage/screenwall contruction phase now and I'm sure I'll have more questions as I get closer to the masking system.

Cheers,
Andy

Scott...awesome job! This is definitely an inspiration and like Andy238 I am at the same stage of my HT and will make for provisions to add this at a later time as time and money is a big concern right now.

Scott: Nice job. Clever mechanical designs with off the shelf parts. I especially liked the way you got your horizontal masking coupled. Good idea. I also might borrow your ideas and make a motor controller for it. If I ever get time and do it, I'll fix you up with one. Thanks for taking the time to share the excellent work.

I wondered why you didn't use matching velvet on the maksing panels, too? Not (acoustically) transparent enough? Too (light) transparent? Velvet "crush" when rolled?

Cheers, Scott

GetGray,

Thanks.... I didn't use the black velvet on the panels because I didn't think it would be acoustically transparent enough. The black Fidelio velvet is a lot thicker and denser and also has a backing material. It is also quite a bit more expensive than the GOM. I didn't do any acoustical testing though so the velvet may have been fine to use. I just based my decision on "gut feeling".

I wish I knew more about motors and motor controllers. If you ever make one, I'd be very interested in buying one from you! I've done a lot of looking at kits and online companies, but I don't know enough about electronics to fully understand what I need.

Here is a diagram of the side masking rollers and cables. This diagram is the top view, looking down on the assembly.
I will post some photos next.

http://home.comcast.net/~scottj0007/theater/MaskingSide_TopView_1.jpg

Hi Scott,
Wonderful creation you have crafted !
Are the two vert masks mechanisms connected in some way, so they will move together ? I see in your drawings the horiz masks move together, one up & the other down. Do you just pull on the edges to move the masks ? The screen shots showing the different ARs
was very helpful.
Thanks for the great drawings, photos & text.
Great job !

John

John,
Right now the two sides are not connected. In my original design, I had planned on connecting them with another cable between the roller bars. However, it is so easy to move the panels by gently pulling or pushing on the edges, I never added the connection. When I add motorization, I will probably connect the two sides so they move together.
- Scott

Sorry for the ad-nausea detail, but it is the only way I thought I could adequately describe my setup.

As I said earlier, I hope to motorize it someday. It should be very easy to attach motors to the roller bars. The trick will be getting a controller system that allows for multiple pre-set stopping points with an IR remote.


Scott, its me agin. I just ran across an option for motorizing masks on another thread here, from poster Gary Murrell at the link below:

http://www.avsforum.com/avs-vb/showthread.php?t=817776

He used a drapery motor from SmartHome that can be RF controlled. Nit sure, your drapes my be too heavy for this motor work with, but take alook & see what you think:

Motor: $100

http://www.smarthome.com/3142.html

RF Rmt: $25

http://www.smarthome.com/includes/showimage2005.asp?img=/images/3150side2big.jpg

Hey Guys,

I've also been thinking about using Scott's design and motorizing it. Here are some of my thoughts:

Motor:
I also saw the Add-a-Motor gadget and am planning on using that or something similar. The only thing I don't like about that particular motor is that you only have "open" and "close" stops. You can't have a third stop for say, 1.85. You've only got open (for 2.35) or close (for 1.78). Although, I suppose a second motor could be added with the stops set for 1.85 viewing.

Side masking:
I was also wondering about what happens when you reverse the motor and how the panels have to move. So I came up a counterweight system to move the panels when revering the motor. I had seen this idea before so I can't take credit it though. ;)

Design change:
I did think about one design change though. Instead of an Al tube and bearings, I was thinking of using off the shelf roller shades from here http://www.blindsgalore.com/ProductList.asp.

I'd pick the cheapest shade since the actual shade doesn't matter as I'd replace it with black GOM anyway. They come with the needed brackets and a continuous loop cord that will fit right in with the motor. Easy automation! Since my screen is 50 inches high I'm planning on a 57 inch wide shade.

So here are some sketches of my implementation of Scott's design. Keep in mind I'm only concerned with side masking. The horizontal masking will be fixed and not adjustable.

What do ya think?

Andy

Hi Scott,

Found your thread a few days ago, and I'd like to say thanks for taking the time to document this, as well as providing the very detailed diagrams!

I had been (slowly) working on an automated side masking system whilst constructing my cinema, unfortunately at the final stages where the masking material was fitted to the system, it didn't quite work as well as I'd hoped due to the material bunching up at the bottom. So, now having seen your design, I am going to attempt to build a version of it (but I only need side masking as I'm using CIH)!

For those talking of motorizing the masking system, the system that I designed uses automation to move the masking to ANY aspect ratio desired - fortunately, this part of my project was the part that actually worked properly! :D

In a nutshell, you pass the desired aspect ratio to the system as an integer between 1 and 2350 (or whatever your max aspect ratio is), and using an optical encoder it will move the masking to the correct point.

I have documented it here: http://www.willcoxonline.com/masking/ which I think would also work using your mechanism, but with a few mechanical modifications of course.
I would imagine that it would be possible to modify the add-a-motor drive unit to add an optical encoder in the same way, however I'm planning to look at alternative motors as I'd like to get the system as silent as possible and the one I've used is a little noisier than I want, and I understand the add-a-motor is a bit noisy also.

Thanks,
Ben

John,
Right now the two sides are not connected. In my original design, I had planned on connecting them with another cable between the roller bars. However, it is so easy to move the panels by gently pulling or pushing on the edges, I never added the connection. When I add motorization, I will probably connect the two sides so they move together.
- Scott

Thanks for the info Scott, good to hear how easily the masking panels move back & forth, prof of a design done right ! Please keep us posted when you do motorized your system. Your theater is amazing, you are blessed my friend !

I just ran across an option for motorizing masks on another thread here, from poster Gary Murrell at the link below:
...
He used a drapery motor from SmartHome that can be RF controlled. Nit sure, your drapes my be too heavy for this motor work with, but take alook & see what you think:
...
Thanks. I have considered that motor but I have some of the same concerns as Andy. Also, it does not appear to be able to move in either direction from a given stopping point. When you reapply power, it continues on in the same direction until it reaches the end and then stops. When you reapply power, it then reverses in the opposite direction.

Also, I would like to find something with IR control rather than only RA control. I would like to be able to program the movement of the masking into a standard universal remote.

So here are some sketches of my implementation of Scott's design. Keep in mind I'm only concerned with side masking. The horizontal masking will be fixed and not adjustable.

What do ya think?
Andy,

Very impressive drawings! Here are a couple of things to consider.

First, the counter weight idea is a very good idea and will actually resolve a number of issues I had with keeping the right amount of tension on the masking material. However, it will require the use of a motor with enough torque to act as a break so that the counter weight doesn't pull the masking closed even after the motor stops.

Second, I found that is was very important to have the rollers spin extremely easily in order for the whole system to work smoothly. My masking glides back and forth with very light finger pressure. All of the off-the-shelf roller shades that I found were not smooth enough and had too much play. This might be a non-issue with the counter-weight design that you have. If so, your design would be much easier to implement.

Hi Scott,
For those talking of motorizing the masking system, the system that I designed uses automation to move the masking to ANY aspect ratio desired - fortunately, this part of my project was the part that actually worked properly! :D

In a nutshell, you pass the desired aspect ratio to the system as an integer between 1 and 2350 (or whatever your max aspect ratio is), and using an optical encoder it will move the masking to the correct point.

I have documented it here: http://www.willcoxonline.com/masking/ which I think would also work using your mechanism, but with a few mechanical modifications of course.
Ben,
Wow! I studied your web site and am very impressed with you electronic design abilities. I'm afraid though that most of it is beyond my level of knowledge. I'm having a hard time even understanding what all the symbols mean on your schematic, let alone understanding how to build it :confused:. I've done a little bit of reading on motor controllers but I always get stumped on the encoders and the programming.

Do you have to re-program the controller if you lose power? Can you move your masking as part of a macro in a universal remote or do you alway have to be hooked up to a PC?

This is my wish-list of what I would like a motorization system to do:

1) It should be able to move both the horizontal and the vertical masking by remote IR and/or RF control. The IR should be “learnable” so that it can be controlled by a universal remote like the Harmony or Pronto series.

2) It should move both the horizontal masking and the vertical masking to a minimum of 5 pre-determined set points for various aspect ratios (4:3, 16:9, 1.85:1, 2.35:1, 2.40:1). It should be extremely accurate and repeatable in its positioning. In addition I would like to be able to move the masking manually with the remote to any other aspect ratio as needed.

3) The masking should move from its current position directly to the preset memory position with the touch of one button on the remote. In other words, it should not have to “reset” itself by returning to the full open or full closed position prior to going to the desired preset position. Also, it would be nice if the controller had a speed control process so that it would quickly move to the desired position and then slow down for the last couple of inches.

4) It should have stop limits for the fully closed and open limits of the masking system.

5) I would also like a wall switch that functions similarly to the remote so that I can move the masking even if I can’t find the remote.

6) The preset stopping positions should be easy to set. For example, I would like to be able to manually move the masking to the desired position and then press a “set” key on the remote followed by the desired Preset Key on the remote to set that desired position.

7) The system should not lose its memory in the event of a power failure.

It seems that all of this should be very do-able for someone who has enough electronic design knowledge and knows where to buy all the parts.

One of my biggest requirement is that they system has to be easy to use. That is probably why I am not overly dissatisfied with my manual setup. Even my wife can set the masking now!

Thanks for posting about your system. It certainly lets me know it is all possible. I'm very impressed!

- Scott

Ben,

Do you have to re-program the controller if you lose power? Can you move your masking as part of a macro in a universal remote or do you alway have to be hooked up to a PC?


Hi Scott, no, nothing has to be reset if the power is lost. I don't have a direct interface to an IR remote control, that would have to be built as an additional interface to make it stand-alone, although in theory I could do that via the HTPC.

However, the way it's designed to work is that you don't actually need a remote control to set the ratio - the video player running on the HTPC (VLC player) automatically detects the aspect ratio of the movie, and sends that data to the masking system. This means that everything is fully automatic, you just play the movie, and whatever the aspect ratio, the masking moves to the correct place!
It doesn't get much more easy to use than that! :D

Cheers,
Ben

This means that everything is fully automatic, you just play the movie, and whatever the aspect ratio, the masking moves to the correct place!
It doesn't get much more easy to use than that!
Very cool!

Ben, that is a nice system. I agree with Scott though... most if the info on the website was over my head too. And I even know what the symbols mean! :D But what if you aren't using an HTPC? I have one but I"m still not sure if I am going to go that route for my final setup.

For me, I"m not looking to go THAT diy on the motor control system. I'd rather just attach a IR contollable motor, set the stops, and be done. Don from HTIQ is working on providing just his motor control system which is pretty robust as far as what we're looking for and what Scott outlined.

So Scott, you think the aluminum pipe is the way to go. There is a Metal Supermarket about an hour or so away from me. I'll have to call them and see what is available. Good catch on the torque and motor break issue. I hadn't thought of that. Hopefully Don's motor will work. If not do you suppose a second motor could do it? Maybe attached to the opposite roller?

I once read about someone using a linear actuator. I wonder if that could be useful somehow...

Andy

I was looking at the linear actuators also but you still need a controller system and I do not think you can get accurate stops out of them accept for full open and full closed. Looks like Dons setup is the way to go.

Nate

Ran across this company, Leg Motorized Systems, which builds motorized drapery systems. Did not see any pricing
given, would imagine they are expensive. They also build an add-on cord pulling motor, looks like it only has two stops as well. Would any of their products be of help to guy guys for powered masking ?

http://legmotorizedsystems.com/

Here is another possible choice for roller shade motors. Saw these Somfy roller shade motors on AV Outlet's web site. The page in the link below shows their in tube roller motors that are battery or tranformer powered. You can buy just the motor or any & all other pieces: brackets, roller tubes (Rollease brand).
From what I read, they have a memory that can hold three setings; FulluUp, Full down & one other specified postion (not sure if these are user setable or dealer does it). Maybe this would help provide (full open for 2.35, full closed for 4:3 & the other position for 16:9). Many are IR controlable & some you can add RF.
I can see them working in the horz position, but how well will any roller shade mech (manual or motorized) work, standing on it's end for vertical masking ?

Take a look & see what you think ?

http://www.av-outlet.com/en-us/dept_496.html


John

Awesome finds, John! Somfy would be the way to go but their IR control is not learnable to other remotes unless you get a $200 module. That would be a deal breaker for me anyway. I just started looking on the av-outlet site. Lots of stuff, more to see...

I'll also fire off for a quote on the LEG motors and see what just the motor is going for. I'll post any replies I get.

Cheers,
Andy

Wow that looks to be perfect get it in the end of Scott's tube and we have motorization. They have an RS232 option perfect for setting exactly what you want.

Nate

I can see them working in the horz position, but how well will any roller shade mech (manual or motorized) work, standing on it's end for vertical masking ?


Thanks for posting the link, these motors look ideal for this application. It looks like it should be fairly straightforward to fit these using the same type of mechanism that Scott has used for his masking.
I also found this link http://www.skycoshade.com/skylight.html which shows this type of motor in use for blinds where the material needs to be kept in tension, such as side masking.

I still think that they would need a different type of control system to cope with more than the three fixed position it appears they support, although that may be enough for some.

Cheers,
Ben

Well, av-outlet has an IR controller called "AVUA-IRRTS Universal Automation Interface" that looks like it will do 5 positions. That's cool. But the price is over $200. That's just the IR interface too. Not cool. Add a motor and you're well over $300. Don's (htiq) motor only package is a less than that (early estimate anyway) and is more precise.

Hey Don, is it soup yet! :D

So why are these things so pricey anyways? :confused:

Great finds guys. I've looked at the somfy motors but they seem a bit pricey and lack some of the flexibility that I think I would want for the masking application. I agree with Andy that Don's (HTIQ) (http://http://www.htiq.com/index.php) setup would be great if he decides to sell a motor only package and it is in the right price range.

Ben, thanks for the neat "skycoshade" site, wish they gave more detail on their products. Look forward to hearing what you find out from either company.

Here is Somfy home page, interesting animations, on their roller shade prodcuts:

http://www.somfy.com/au/index.cfm?page=/au/home/products/roller_shutters/control_options&language=en-au

Ran across this link (news from 11-14-07) about Somfy having a next gen "ILT" motor coming out. From what I read the motor has built in intelligence, each mtr has a unique address. The mtrs on the network communnicate via a protocol allowing intergration w/ 3rd party automation sys capable of dry contact, RF, IR, RS-232 or RS-422. See link below:

http://hiddenwires.co.uk/resourcesnews2007/news20071114-03.html

Guess for a motor to stop in the right place (putting the masks where we want it) means that mtr has to be smart
& know exactly where it is & where it is going & that takes a control system of some kind to make it happen. Starting to sound expensive... :eek:
Hey Don @ HTIQ, how's your system coming along ?

John

Found this, might be of some use.
http://www.remotecontrolcurtain.com/

Mmmm. Interesting....

What would make for a good motor to use on masking systems ? I ran across the web site below & they had many types. They have all sorts of hobby & robitics stuff on their site. www.alltronics.com

Found one 12VDC Pittman type motor w/solenoid (part# 24M015) with encoder attached for $20.
There was a 24VDC Coleman gearmotor for $20 (# FYQF63600 30-5).
An AC gearmotor w/brake (# 23M030), 147 RPM,
Then there was a motor with a solenoid activated brake that releases upon power up for $20
A US Digital optical encoder (Part# E2-1016-250-G) 1016 pulses per revolutionwith 1/4" shaft. Does anthing sound useful here ?
Figured a slow RPM was useful & maybe a controller would need an optical sensor to get feedback from the motor.

John

What would make for a good motor to use on masking systems ? I ran across the web site below & they had many types. They have all sorts of hobby & robitics stuff on their site. www.alltronics.com


Hi John,

The criteria I would look for in a motor are that it needs to be geared, low voltage DC to allow easy solid-state switching (i.e. no relays) and speed control if desired, an encoder to give feedback for precise positioning, and quiet operation. It may or may not need an electro-magnetic brake, depending on the intertia of the rotor and gearbox of the particular motor.

Cheers,
Ben

Hey Don, is it soup yet! :D



Not soup just quite yet, but it's on the burner. I want to roll out the IR/RS232 combo, as well as the dual - motor controller. These controllers have been "rock-solid" for about 2 years now. The encoder makes it so you can have presets (up to 10).

These will be ready at the end of January.

Don

I noticed in the regular screen section a recent post by Danny Marvomatis regarding his new Marvomatic controller (used to control a Stewart masking system). See the link below:

http://www.avsforum.com/avs-vb/showthread.php?t=975908

What do you guys think ? Wonder if it can by used or adapted to work with 4-way masking (buy a second board for vertical masks)? It has three presets; 1.85, 2.35 & 2.40, plus manual toggle for top & bottom masks. No pricing shown.

HTIQ's controller has 10 presets, I believe. :)

Not soup just quite yet, but it's on the burner. I want to roll out the IR/RS232 combo, as well as the dual - motor controller. These controllers have been "rock-solid" for about 2 years now. The encoder makes it so you can have presets (up to 10).

These will be ready at the end of January.

Don


Hi Don, when you say dual motor controller, are you meaning that one controller will control a seperate motor for Horz masks & a seperate motor for the Vert masks ?

Would these need to be a specific type motor or even a certain model motor to work properly & accurately with your controller ?

Do you have a price for this dual controller at this point ?

Thanks ! :)

John-
I have a dual-motor controller. The 4-way masking can be done with 2 motors. You will need 12VDC gearmotors rated at about 175 oz-inches.

Don

Don,
Thanks so much for the info.
Good luck with all your many projects that you have going on. You are a busy man!

John

Thanks Scott for a great thread....you just gave me another project to do this winter..... I just replaced my 16X9 screen with a CIH by Carada and have been considering the side masking idea then I ran into this thread...

Okay to pm you and throw some idea's your way on just a side masking system?

tia

Keith

Thanks Scott for a great thread....you just gave me another project to do this winter..... I just replaced my 16X9 screen with a CIH by Carada and have been considering the side masking idea then I ran into this thread...

Okay to pm you and throw some idea's your way on just a side masking system?

tia

Keith


Keith;
If possible, I would appreciate if you could keep your idea exchange public, i.e. by adding to this thread or if needed by creating a new one. One the main reasons for having this forum is to provide a platform for others to learn as well....
Having said this (selfish me), I would be very interested in your thoughts on how to make a masking system with my Carada Criterion CIH setup... :) The problem I am facing right now is to get the masking panel close enough to the screen material (< 1/2") so it does not cast a shadow. Any pointers/ideas?
____
Axel

Axel,

Will do that, and you are correct this is a public forum and hopefully share some idea's and maybe spark an idea from other members. Working on the same problem you are having trying to get the masking material close enough to not cast a shadow...

Keith

Most of the commercial screen companies mount the screen material on the back side of the frame. Since the frame has a dimension, that means that any masking of the screen places the masks some distance away from the screen material itself.

From my experience, this doesn't pose a problem, so long as your masks are not too far from the screen. Since your projector blasts light straight on, the "shadows" will be behind the masks.

Don

Most of the commercial screen companies mount the screen material on the back side of the frame. Since the frame has a dimension, that means that any masking of the screen places the masks some distance away from the screen material itself.

From my experience, this doesn't pose a problem, so long as your masks are not too far from the screen. Since your projector blasts light straight on, the "shadows" will be behind the masks.

Don

Yep, that's it Don!
In my case with the Carada Criterion this distance is approx. 1.5" and the masks unfortunately cast a noticeable shadow from the first row (primary seating location - approx 12 ft away from screen). Any good ideas for me?
____
Axel

Axel-
If you are masking a screen that has a recessed frame, then there's no getting around the 1.5 inches for the masks. In fact, this may end up being more than 1.5 inches, since the masks typically don't sit right on the frame.

I just did a theater here in LA, where we masked a 12 ft Carada. Depth of frame is probably same as yours. However, I haven't noticed any ill effects of having the masks that far away from the screen material. Again, it will depend on your seating distance as well. The only way around this is to turn your screen around. ;)

Don

I’ve been away a couple of days. Great discussions!

Not soup just quite yet, but it's on the burner. ...These will be ready at the end of January.
Don, this is very good news! Keep us posted.

John-
I have a dual-motor controller. ... You will need 12VDC gearmotors rated at about 175 oz-inches.
Don, With the package you are putting together, will you include your motors? Also, have you added non-volitile memory to your controller so it doesn't loose its settings if the power goes off?

I noticed in the regular screen section a recent post by Danny Marvomatis regarding his new Marvomatic controller (used to control a Stewart masking system). See the link below:
http://www.avsforum.com/avs-vb/showthread.php?t=975908
What do you guys think ? …
Very interesting prototype. It looks like the Marvomatic controller has some real potential if Danny continues his R&D. His video is pretty cool too. Currently however, I think Don’s controller has more features and is much further developed and tested. It looks like Don’s HTIQ controller will be available as a stand-alone product very shortly, but it looks like the Marvomatic might be quite some time away from production.

…Okay to pm you and throw some idea's your way on just a side masking system?
Keith
Keith, It is fine to PM me, but I agree with Axel that if it is a question of general interest, it would be best to keep it public.

Keith;
Having said this (selfish me), I would be very interested in your thoughts on how to make a masking system with my Carada Criterion CIH setup... :) The problem I am facing right now is to get the masking panel close enough to the screen material (< 1/2") so it does not cast a shadow. Any pointers/ideas?
Axel

Axel, Keeping my masking as close as possible to my screen was a big concern of mine as well. The only ideas I have are 1) As Don already mentioned, if possible you might consider mounting your screen to the back side of the frame so that you eliminate the “box effect” of the frame itself. 2) The only other idea I would have would be to build a lip on the edge of your vertical masking panel that protrudes towards the screen. The lip could be built from very thin and lightweight material since it would not have any load bearing requirements. You could cover it in the same material as the masking panel. The downside to this option is that you would not be able to retract the masking past the edge of the screen because the lip would catch on the side frame. I’m not sure if this would be a problem in your setup or not.

Axel

I think Scott is talking about what I was going to try and do.... Basically give up a little screen real estate on either side to have a cutout that would travel very close to the screen while the rest of the material would stay the 1.5" away.... maybe using a piece of plastic or light weight fiber board?

Hopefully I get a drawing together and post it to see what everyone thinks...

Don and Scott thanks again for the assistance and valuable ideas!!

Scott maybe some time if you are in the Denver area you could stop by to see my modest theater.

Keith

Scott maybe some time if you are in the Denver area you could stop by to see my modest theater.
KeithKeith, I sent you a PM.
- Scott

Don and Scott thanks again for the assistance and valuable ideas!!

Keith

No problem, Freddie...er, Keith! Keep on truckin'!

Don

Hey Guys,

I've been thinking about this whole masking automation thing since this thread started. Scott's design is awesome and very doable for a DIYer. But the automation part is driving me nuts! :eek:

Everyone who posted here has had great ideas and great resource finds. It looks like everything we need to motorize Scott's design is out there. We've found motors, motor contollers, encoders, relays, IR controls, and hardware. But unfortunately not in one nice and tidy kit. Wouldn't that be nice ;) One thing I found out is I don't know enough about these gadgets to know how to connect them together!

From what I gather the best and most accurate control system uses a stepper motor, a stepper motor controller, and an optical encoder. I understand how a stepper motor works (is controlled by voltage pulses th rotate a specific amount per pulse). I understand what the encoder does (creates a pulse based on a rotating disk with light/dark bands). The part I don't know enough about is how these things work together, or rather how they are connected together, to make a complete control system. I'm just not an electronics whiz. Does anybody know how this stuff should be integrated that can help us out? I know Don does but he's working on his commercial version and I'm not sure if he is willing to share his secrets - which I totally understand, btw.

So here are some of the puzzle pieces. Also look at John's post above (# 79) for good finds.

So how do we put all this stuff together? :confused:

Andy

Contollers:
This is a very cool controller. For servos though not sure if useful for us. Includes an IR module and stores programming in EEPROM: http://www.pontech.com/products/sv200bc/index.htm

Controller kit: http://www.allelectronics.com/cgi-bin/item/SMKIT-2/305/STEPPER_MOTOR_CONTROLLER_KIT_.html
There a bunch more contollers out there too.

Encoder: http://www.alltronics.com/cgi-bin/item/24T001/search/USDIGITAL%2DE2%2D1016%2D250%2DG%2Doptical%2Dencoder

Motors: http://www.allelectronics.com/cgi-bin/category/400400/DC_Gear_Motors.html

IR Relay kit: http://www.alltronics.com/cgi-bin/item/KIT_142/29/12%2DChannel%2DIR%2DRelay%2DBoard%2DKit
For a non-encoder based control system... I think.

Yes, the putting it all together is the hard part. Without having a kludge of parts anyway. An elegant solution that one can sell is tough though. In the US anything that has a microprocessor in it requires FCC part 15 compliance/certification. Unintentional radiators they are called (assuming no RF control), and they require electromagnetic emmissions and conducted radiation tests. The lab costs for that are very high, and that's if you pass. CE is worse adding ESD immunity testing at least. People think it's not big deal but it is really. The fines if you sell something that is not FCC certifiable can be as high as $10k per day :eek:. Even if you sell it as a "kit" (which is also against their rules). And they are quite serious about it.

Good news is if you only make 5 or less, for personal use, and don't sell them, you can be exempt.

That 's the beauty of a DIY and a forum though. If you can come up with a workable solution that people can put together from off-shelf parts, then they can get around the FCC regs and potential fines. You just can't bundle it up and sell it as a kit. Which bites :(. Of course chances of the FCC triangulating your device and knocking on your door may be low, but if you sell one of the buggers, and they get wind of it not being compliant, then you are way out on the proverbial limb.

I think there are outs for just selling a component (i.e. a circuit board that is a dedicated motor controller circuit only) so long as it is not a functional system. So alas, we are held to using piece parts to make it work. Still doable though.

As Kramer would say, "oh, it's doable."

Just not by myself. :)

Working with piece parts works for me. Heck, I really don't care what the contraption looks like. It'll be "behind the scenes" anyway. I'm not looking to sell anything. It's for my HT.

I just don't understand how the encoder/controller gizmos are all connected to be able to do thier stuff when I hit an IR remote button to go from 2.23 to 1.85 to 1.78 and back again.

Andy

I really like the idea of using a stepper motor as they are accurate and do not need relays or optical encoders to determine when the reach a specific location.

What I am unclear about is how to take the stepper motor kit as mentioned above and create specific points (1.33, 1.66, 1.78, 1.85, 2.35) and have it be controlled via IR.

it seems like the pieces to the puzzle are there, now we just need to connect them.

Itai

From what I gather the best and most accurate control system uses a stepper motor, a stepper motor controller, and an optical encoder. I understand how a stepper motor works (is controlled by voltage pulses th rotate a specific amount per pulse). I understand what the encoder does (creates a pulse based on a rotating disk with light/dark bands). The part I don't know enough about is how these things work together, or rather how they are connected together, to make a complete control system. I'm just not an electronics whiz. Does anybody know how this stuff should be integrated that can help us out? I know Don does but he's working on his commercial version and I'm not sure if he is willing to share his secrets - which I totally understand, btw.


Hi Andy,

There are two different approaches to accurate position control - you could use a stepper motor, which as the name suggests rotates in a number of steps, managed by a controller. Therefore, absolute positioning can be achieved by use of a 'home' position sensor, then telling the motor to rotate the correct number of steps needed to get the motor to a specific position.
Alternatively, you could use a standard motor coupled with an encoder, so you drive the motor and count the pulses received which allows you to get to a known position.

One of my previous projects from a couple of years ago was designing an automated curtain controller, and at that time I had decided a stepper motor was the best way forward. I documented some of the system here: http://willcoxonline.com/Curtain/ which may give you a little insight into steppers and how they work. I abandoned the project as I moved on to other things, I decided it was a bit over-engineered for a curtain controller, and the problem is that the control system used to drive a stepper is more complex than a conventional motor.

For somebody who has some basic electronics knowledge, it really is not that hard to design a system that can do everything that is needed to build an automatic masking system.
I've already posted a link to my site which shows a schematic of a microcontroller based system with encoder feedback and RS232 interface. Adding IR control is not a big deal, but it's not something that I'm particularly interested in at this stage, which is why I haven't got that on my control system.

BUT, as GetGray says, it's one thing for an electronics hobbyist to build a system for their own use, but a completely different kettle of fish to build, sell and support a system commercially!

So as far as I can see there are three ways to achieve a motorised masking system:
1) Buy an off the shelf complete screen/masking package for $$$$$
2) Buy a kit that will allow you to construct a masking system from a set of 'black-box' parts
3) Build a system from scratch including electronics etc

Option 1 and 3 already exist (and I've already provided an example schematic and source code for option 3, which shows how the various parts are interconnected, which seems to be the main question at the moment), and it sounds like Don has a system in the works that will satisfy option 2, which would be the most suitable solution for those d-i-y'ers that don't have any electronics knowledge.

So, those that are asking how all these components fit together, I've already shown you an example. But, unless you know how to build it, and by it's very nature it needs technical electronics knowledge to understand, then it's not going to be much help.

To use an analogy, although you can learn how a car works, and can buy wheels, chassis and an engine, unless you have some mechanical knowledge and the tools to put them together, you can't just build a car. (but you might be able to build a kit-car ;-))

Cheers,
Ben

Hi! Thanks for sharing this, both the masking systen, and the picaxe automation system. I have no experience with microcontrollers, but it seems like a very interesting project. Is the number of sectors on the encoder determined from the movement pr bit of the mask?

Gunnar

Axel

I think Scott is talking about what I was going to try and do.... Basically give up a little screen real estate on either side to have a cutout that would travel very close to the screen while the rest of the material would stay the 1.5" away.... maybe using a piece of plastic or light weight fiber board?

Hopefully I get a drawing together and post it to see what everyone thinks...



That is exactly what I've already planned to do! I want to do a bevelled edge, matching that of the screen frame with the masking board inset into the frame, travelling as close to the screen material as possible. (I'll be using the Carada Masquerade frame for it's' automated vertical masking).

In fact a while back I made
a very crude drawing (my first time using Google's Sketchup). The proportions aren't perfect - the side mask should be the same width as the side of the frame for my design. Also, this does not show the side mask inset into the frame, but rather just beside the frame. The gray attached to
the side of the mask indicates what would be black material, pulled along
by the mask:

http://img441.imageshack.us/img441/5426/maskingsketchfirsttry2ji5.jpg

Hi! Thanks for sharing this, both the masking systen, and the picaxe automation system. I have no experience with microcontrollers, but it seems like a very interesting project. Is the number of sectors on the encoder determined from the movement pr bit of the mask?


I experimented with encoder wheels with different numbers of sectors, and found that any higher resolution than the ones you see in the photos would not work with the reflective opto-sensor that I was using. As it worked out, the inertia in that motor & gearbox is the limiting factor so a higher resolution encoder would not give me any extra precision.

Commercially available encoders use a slotted wheel rather than a reflective opto, and give resolutions of hundreds or thousands of pulses per revolution, but of course need would need a suitable drive train to make use of the extra precision.

What I'd like to do now is built a mechanism like Scott's, but fitted with one of those somfy tubular motors coupled with a proper encoder, its just a shame that the motors are so expensive...

Cheers,
Ben

BTW,

Most of us would like a side masking system with pre-sets. But if one is willing to give up that convenience, isn't it possible to go with a good automated curtain rod?

From my reading BTX Drapery System 5060 regarded as among the best in terms of reliability, smoothness of operation etc:

http://www.btxinc.com/pages/drap5060.htm

Might that work to pull the side masking boards some of us are talking about?

Ok, I was thinking about an idea to fit a somfy tubular motor to Scott's system, whilst slightly simplifying the mechanism...

My idea is to take the mechanism as shown here:
http://home.comcast.net/~scottj0007/theater/MaskingSide_TopView_1.jpg

with a somfy motor fitted to the vertical tubing, but replace the end pulleys with spring balancers (http://www.pvrdirect.co.uk/productInfo.aspx?source=froogle&utm_source=Products&utm_medium=Froogle&catref=ATB0615)instead of running the cables via pulleys back to the vertical tubing.
I'm thinking the advantage of the balancers is that you wouldn't need to adjust the tension using turnbuckles, and eliminate the problem of needing to adjust the diameter of the tubing where the cables feed back using tape.
The spring balancers will provide tension to the material to allow it to be pulled off the tubing and keep it flat and tight.
Unfortunately the spring balancers aren't cheap, and it would need 4 for just a side masking system. Any thoughts?

Cheers,
Ben

Ben,

Thanks for the link to your curtain project. One of the ad links on the bottom of your page links to a robotics site which was very helpful too. Even had a YouTube video showing a DC motor, motor controller, servo controller, and encoder set up.

Yeah, Somfys would be great. They are really nice and quiet. But just too expensive (for me anyway). I think the cheapest one I saw was at AV-Outlet for $108.

For my implimentation of Scott's design, I was thinking about using counter weights to keep tension on the mask. See my diagrams a ways back (bottom of page 2 I think).
Would that work?

For my implimentation of Scott's design, I was thinking about using counter weights to keep tension on the mask. See my diagrams a ways back (bottom of page 2 I think).
Would that work?

Ah yes of course! Yes can't see any reason why it wouldn't work - however you would have to make sure you have enough distance between the bottom of your screen and the floor to give enough drop for the bottom weight to fall.

Another alternative I've thought of is to use a spring loaded retractable roller blind instead of a somfy motor powered one, and then use a conventional geared motor to wind up the cables onto some sort of drum, which then wouldn't need counterweights or spring balancers.
However for this sort of approach (and the weighted one) the motor system would need an electromagnetic brake otherwise the mechanism could retract when the motor is not powered. I understand the somfy unit has an integral brake which is probably part of the reason for it's cost.

Also, going back to the subject of IR control, to add this to a PIC based system I have had a look around, and would probably use something like this: http://www.infraredremote.com/8pindecoder.htm
then use one of the handsets such as these: http://www.infraredremote.com/8keysmall.htm which would give a nice neat solution.

Cheers,
Ben

Ok, I was thinking about an idea to fit a somfy tubular motor to Scott's system, whilst slightly simplifying the mechanism...

My idea is to take the mechanism as shown here:
http://home.comcast.net/~scottj0007/theater/MaskingSide_TopView_1.jpg

with a somfy motor fitted to the vertical tubing, but replace the end pulleys with spring balancers (http://www.pvrdirect.co.uk/productInfo.aspx?source=froogle&utm_source=Products&utm_medium=Froogle&catref=ATB0615)instead of running the cables via pulleys back to the vertical tubing.
I'm thinking the advantage of the balancers is that you wouldn't need to adjust the tension using turnbuckles, and eliminate the problem of needing to adjust the diameter of the tubing where the cables feed back using tape.
The spring balancers will provide tension to the material to allow it to be pulled off the tubing and keep it flat and tight.
Unfortunately the spring balancers aren't cheap, and it would need 4 for just a side masking system. Any thoughts?

Cheers,
Ben

Ben, Ran across this web site & McMaster's has "spring balancer" from ~$20 - $33, not sure if these are good enough for what we are talking about (travel: 1.7' to 4.7' & load cap from 1 - 12 lbs). Go to the link below & type in what you are looking for, the cheaper items are a the top of the page: www.mcmaster.com

John

I ran across this company's products this evening; Solarbotics. They have two motor controllers that look interesting; "Secret Motor Driver Kit" (#KSMD) for $ 12.50 & the "L298 Compact Driver Dual H Bridge Kit" for $ 17.95(# KCMD). While interesting looking I have no idea how to interface them with IR relays or to a micropressor to tell them where to turn the motors too, that takes someone writing code...

Secret Mtr Driver # KSMD According to what the mfg says, this board can put placed inside a servo motor & convert it to a gearmotor...
http://www.solarbotics.com/products/k_smd/

# KCMD L298 kit for dual motor control
http://www.solarbotics.com/products/k_cmd/

Ben, would this code wheel "Wheel Watcher" setup act enough like an a real encoder to be of help:
http://www.solarbotics.com/products/gmww02/

Their assenbly instructions are even a bit funny.

Can also be purchased from: www.hobbyengineering.com

Nice find on the Secret Motor Driver, John.

... While interesting looking I have no idea how to interface them with IR relays or to a micropressor to tell them where to turn the motors too, that takes someone writing code...

That's what is so cool about this: http://www.pontech.com/products/sv200bc/index.htm

You can store a program on the chip that will postion the motor using IR input. Follow the link and checkout the manual at the bottom of the page. Excellent examples of programming code in there. From what I gather, you'd connect the board to a PC to fine tune the program (motor position, IR inputs, etc) then store it on the EEPROM chip. It can also control more than one motor.

Go here: http://www.trossenrobotics.com/store/c/2666-DC-Motor-Controllers.aspx?gkw=motor%20controller&gclid=COeIldPRh5ECFQspFQodwjRCFg

and check out the tutorial. That is exactly the setup what we need!... I think. :)

For my implimentation of Scott's design, I was thinking about using counter weights to keep tension on the mask. See my diagrams a ways back (bottom of page 2 I think).
Would that work?
Another alternative I've thought of is to use a spring loaded retractable roller blind instead of a somfy motor powered one, and then use a conventional geared motor to wind up the cables onto some sort of drum, which then wouldn't need counterweights or spring balancers.

If you motorize the masking, I really like the idea of using positive tension on the masking such as counter weights, spring balancers, or the spring loaded rollers. Those solutions resolve a number of issues I had with my manual system.

However, I suspect that there may be a potential problem with either the counter weight design or the spring balancer design. Both of these designs put tension on the masking by pulling the leading edge of the masking away from the roller. The motor however would be attached directly to the roller and the encoding system would always count the exact position of the roller, not the masking itself. If there is any STRETCH to the masking material, over time the leading edge of the masking might creep towards the source of the tension and the motor controller settings would have to be re-adjusted to account for the stretching of the masking material.

Ben's solution of using a spring loaded retractable roller would not have this problem because the connection to the motor would be from the leading edge of the masking directly to the motor drum via a cable. Any stretch in the masking material would not affect the position of the leading edge of the masking.

I think that Andy's counter weight design could be modified to be a retractable roller design by attaching the weights to a cable that wraps around the roller rather than to the leading edge of the masking. This modification would only require one weight on the roller.

What do you think?

Hi again. The tutorial is actually here: http://www.youtube.com/watch?v=X4stWDy-bPA "How to Control A DC Motor from Your Computer".

Ben, Ran across this web site & McMaster's has "spring balancer" from ~$20 - $33, not sure if these are good enough for what we are talking about (travel: 1.7' to 4.7' & load cap from 1 - 12 lbs). Go to the link below & type in what you are looking for, the cheaper items are a the top of the page: www.mcmaster.com


Yes that's the kind of thing I was thinking about. I actually found some on ebay UK for £6.50 each, which is a much better price, and has adjustable tension.

I ran across this company's products this evening; Solarbotics. They have two motor controllers that look interesting; "Secret Motor Driver Kit" (#KSMD) for $ 12.50 & the "L298 Compact Driver Dual H Bridge Kit" for $ 17.95(# KCMD). While interesting looking I have no idea how to interface them with IR relays or to a micropressor to tell them where to turn the motors too, that takes someone writing code...

Secret Mtr Driver # KSMD According to what the mfg says, this board can put placed inside a servo motor & convert it to a gearmotor...
http://www.solarbotics.com/products/k_smd/

# KCMD L298 kit for dual motor control
http://www.solarbotics.com/products/k_cmd/

Ben, would this code wheel "Wheel Watcher" setup act enough like an a real encoder to be of help:
http://www.solarbotics.com/products/gmww02/


Ok the H-bridge kit is a way to drive a DC motor in forward or reverse, by using low-level control signals. This could also be done with relays as an alternative.

The secret motor driver is designed for Radio Controlled model type servo motors, which I think would probably not have enough torque for this application. That encoder wheel is pretty much exactly the type of thing that we need though, although fully enclosed types are available elsewhere which may be a bit more robust.



That's what is so cool about this: http://www.pontech.com/products/sv200bc/index.htm

You can store a program on the chip that will postion the motor using IR input. Follow the link and checkout the manual at the bottom of the page. Excellent examples of programming code in there. From what I gather, you'd connect the board to a PC to fine tune the program (motor position, IR inputs, etc) then store it on the EEPROM chip. It can also control more than one motor.


The problem with this controller is that it is designed for use with servo motors. This type of motor uses a different type of feedback mechanism, that gives absolute positioning of a shaft. However, the shaft does not rotate continuously, and usually has a max rotation of less than 360 degrees (for RC type servos anyway) so you can basically just set a desired angle on a shaft, which wouldn't be useful for this type of application

If you motorize the masking, I really like the idea of using positive tension on the masking such as counter weights, spring balancers, or the spring loaded rollers. Those solutions resolve a number of issues I had with my manual system.

However, I suspect that there may be a potential problem with either the counter weight design or the spring balancer design. Both of these designs put tension on the masking by pulling the leading edge of the masking away from the roller. The motor however would be attached directly to the roller and the encoding system would always count the exact position of the roller, not the masking itself. If there is any STRETCH to the masking material, over time the leading edge of the masking might creep towards the source of the tension and the motor controller settings would have to be re-adjusted to account for the stretching of the masking material.

Ben's solution of using a spring loaded retractable roller would not have this problem because the connection to the motor would be from the leading edge of the masking directly to the motor drum via a cable. Any stretch in the masking material would not affect the position of the leading edge of the masking.

I think that Andy's counter weight design could be modified to be a retractable roller design by attaching the weights to a cable that wraps around the roller rather than to the leading edge of the masking. This modification would only require one weight on the roller.

What do you think?

I think you have a very good point about the fabric stretching with that first design, and that could definately be a problem, as you describe.
I can't quite picture what you mean about wrapping a cable round the roller with a counterweight though - what would be pulling the leading edge of the masking in this case?

Lots of good ideas coming out now, we just need to put the right ones together!

Cheers,
Ben

The problem with this controller is that it is designed for use with servo motors. This type of motor uses a different type of feedback mechanism, that gives absolute positioning of a shaft. However, the shaft does not rotate continuously, and usually has a max rotation of less than 360 degrees (for RC type servos anyway) so you can basically just set a desired angle on a shaft, which wouldn't be useful for this type of application

Yes it is a servo controller. But, you can use a PWM controller with a DC motor. Check out the tutorial in the YouTube link I posted. A servo motor can also be easily modded to run continously and provide high torque. ;)

Mmmm, I'm not sold on the stretching being a big problem. I mean, we're not pulling against a lot of resistance (especially if we use bearings) and the counter-weight or wrapped cable is only keeping it taught. We're not really stretching it that tight. IMHO anyway.

Mmmm, I'm not sold on the stretching being a big problem. I mean, we're not pulling against a lot of resistance (especially if we use bearings) and the counter-weight or wrapped cable is only keeping it taught. We're not really stretching it that tight. IMHO anyway.

I guess it depends on the material used, and the amount of force applied to keep the material taught - I think this is the sort of stuff that can only really be proven by building a prototype!

Cheers,
Ben

Agreed. I guess it would depend on say, if you use velvet or an AT material like GOM. Those fabrics probably won't stretch the same.

Ok, who's going to build the first prototype? :D

Still looking for an answer for my question, quoted below. Thanks:

BTW,

Most of us would like a side masking system with pre-sets. But if one is willing to give up that convenience, isn't it possible to go with a good automated curtain rod?

From my reading BTX Drapery System 5060 regarded as among the best in terms of reliability, smoothness of operation etc:

http://www.btxinc.com/pages/drap5060.htm

Might that work to pull the side masking boards some of us are talking about?

Hey Rich,

Sure. There are several AVSers who use a drape system to move masking panels. You're right too, BTX is one of the better systems. I think Makita is up there too. Do a search for "masking" in the dedicated theater construction forum as well as the 2.35 CIH forum and you should find some threads about it.

I just don't have the room on the sides of my screen to use this method. If I did, I probably would. It's pretty easy to incorporate.

Cheers,
Andy

Thanks Andy.

Ben, Is this what you mean by spring loade roller ? Here is a product from "Rollease" for roller shades....

http://rollease.com/SpringAssist.htm

You can buy the SpringAssist here: http://www.av-outlet.com/en-us/dept_511.html
At the bottom of the page. Cheap too!

Now that I think about it more. That little gizmo would be great since it'll fit right into the 1.5" diameter aluminum tubes AV-Outlet sells too! Hmmmm.....

Ben, Is this what you mean by spring loade roller ? Here is a product from "Rollease" for roller shades....

http://rollease.com/SpringAssist.htm

Yes that's the sort of thing I was thinking of.

Also, have a look at this pdf here: http://www.silentgliss.com.au/doc/doc_download.cfm?29A420EB306E2C0BE350AB142A87AE84

There's quite a few different blind systems there that might be suitable, especially the Tess 100 system.

Edit: In fact, the Tess 120 looks perfect, as it incorporates side guides which would mean it could be directly used in the orientation needed for side masking: http://www.windowworldhi.com/Specifications/GuthrieDouglas/Tess%20120%20data.pdf
Can't seem to find any prices anywhere though!
Ben

Boy, wouldn't that system be sweet. Almst plug & Play.
Betcha they use Somfy motors... and you know what that mean$. :D

Ran across this company, GoelstAmerica, someone may have mentioned them in regards to skylight shades. Maybe this would work for those who would want to use curtains as masks. Below is a pdf link for their 6200 series 24V motorized drapery rod, their lit says it has a variable speed motor, soft launching / docking & up to 5 presets programable. Of course there is no pricing on their web site Their US office is near Atlanata. Take a look: :)

http://goelstamerica.com/fileadmin/product-pdfs/6200%20UK.pdf

John

Ran across this company, GoelstAmerica, someone may have mentioned them in regards to skylight shades. Maybe this would work for those who would want to use curtains as masks. Below is a pdf link for their 6200 series 24V motorized drapery rod, their lit says it has a variable speed motor, soft launching / docking & up to 5 presets programable. Of course there is no pricing on their web site Their US office is near Atlanata. Take a look: :)

http://goelstamerica.com/fileadmin/product-pdfs/6200%20UK.pdf

John


OMG that's perfect! Exactly what I"m looking for! I'm one of the few who will be using a variable image size, 4 way masking (and not merely CIH) so those pre-sets are a god-send.

I only hope it isn't going to be as expensive as it looks :eek:

Anyway, I've contacted the company and they only do quotes via email, so I'll
be sending an email to check them out.

Thanks very much!

....
Anyway, I've contacted the company and they only do quotes via email, so I'll
be sending an email to check them out.
...

Please let us know what you find out.

TIA!
____
Axel

When I was a kid, I used to use magnetic "Reed Switches" in my projects as limit switches. You use a magnet on the moving part and the reed switch can be mounted on an adjustment plate. Magnetic alarm switches, used on doors and windows are a good example of this type of system.

What if you mounted a magnet or magnets on your cable with heat shrink tubing, far enough away from the pulleys not to interfere with them. And you mount the limit switches on sliding adjustment plates, allowing you to set your stops or limits.

Below, is a radio shack link to the type of switch available at a low cost. You can take the magnet out of the plastic case and heat shrink it to the cable assembly and use the reed switch housing as-is. The switch housing already has screw holes for mounting.

http://www.radioshack.com/product/index.jsp?productId=2419298&cp=2032060.2032330.2032348&parentPage=family

Actually, you can use the normally closed contacts of the switch and when the magnet activates the reed relay, power is cut. You then re-apply power when needed, which overrides or bypasses the limit switch.

Control of your motor assembly can all be accomplished with simple relays which cut voltage continuity to the motor, stopping its rotation at your preset limits. Everything can be either linked to your projector's trigger outputs or controlled with Xantech IR activated relays.

I know this concept is not a very elegant solution, but sometimes inexpensive and simple implementation is the best means to an end.

Ran across this company, GoelstAmerica, someone may have mentioned them in regards to skylight shades. Maybe this would work for those who would want to use curtains as masks. Below is a pdf link for their 6200 series 24V motorized drapery rod, their lit says it has a variable speed motor, soft launching / docking & up to 5 presets programable. Of course there is no pricing on their web site Their US office is near Atlanata. Take a look: :)

http://goelstamerica.com/fileadmin/product-pdfs/6200%20UK.pdf

John


Hey folks. If I wanted to use the above product, with the 5 presets used for
variable side masking widths, would you suggest I go for the IR or the RF remote control option?

Ideally I would like my RTI T3 universal remote (which can do both IR and RF, and works with a universal RP6 controller) to have pre-programmed image width selections.

Thanks.

Hi Audiodynamics,

Thanks for the info, simple is always a good plan. I have
a couple of questions;

Does it take special wiring to start the motor once again, after it has been shut off by the first reed swt ?

Will each reed switch position require a seperate relay to break the current flow for each new AR stop ?

Would someone sketch this out and display it for us ?

Do you think proxmity switches would work in the same way as a reed swt ?
-------------------------------------------

Rharkenss, do let us know what they tell you. They sent me a pdf of the instruction maual. I can email that, if somone wants it, just PM me.

John

Well the quote for the GoelstAmerica 6200 motorized drapery system was actually pretty good, comparatively and all things considered.

The quotes I was getting for a 160" BTX BTX Drapery System 5060 were closer to $2,000. Whereas the quotes for the same size Goelst system is several hundred dollars less, and then after the discount for my company (you might have to have a company, or be an installer to purchase) it's lowered another $440 more!

Given the Goelst system does even more than the BTX system, especially those luscious
5 pre-sets and apparent ease of installation, I may have found my masking/curtain system!

Cheers,

Contgrats Rich!
Concerning RF vs. IR. I found that in most cases RF communication protocols, unlike IR, can not be learned by universal remote controls. So in short, I would definitely verify that RF is in fact an option for you, in case you went that route.
____
Axel

Awesome, Rich! I contacted Goelst too. The main company won't quote or sell to individuals. I asked for info on just the motor kit, 6200-00 Motor Set and the 6220 Drive Belt.

Their reply:

"I’m sorry, but I cannot quote directly to an individual. If you will let me know where you are located, I’ll refer you to a dealer. However, we normally, do not sell components to end users, only assembled products."

I'm still waiting for the dealer info.

Rich, can you get a quote on the motor set and drive belt?

Andy

When I was a kid, I used to use magnetic "Reed Switches" in my projects as limit switches. You use a magnet on the moving part and the reed switch can be mounted on an adjustment plate. Magnetic alarm switches, used on doors and windows are a good example of this type of system.

What if you mounted a magnet or magnets on your cable with heat shrink tubing, far enough away from the pulleys not to interfere with them. And you mount the limit switches on sliding adjustment plates, allowing you to set your stops or limits.

Below, is a radio shack link to the type of switch available at a low cost. You can take the magnet out of the plastic case and heat shrink it to the cable assembly and use the reed switch housing as-is. The switch housing already has screw holes for mounting.

http://www.radioshack.com/product/index.jsp?productId=2419298&cp=2032060.2032330.2032348&parentPage=family

Actually, you can use the normally closed contacts of the switch and when the magnet activates the reed relay, power is cut. You then re-apply power when needed, which overrides or bypasses the limit switch.

Control of your motor assembly can all be accomplished with simple relays which cut voltage continuity to the motor, stopping its rotation at your preset limits. Everything can be either linked to your projector's trigger outputs or controlled with Xantech IR activated relays.

I know this concept is not a very elegant solution, but sometimes inexpensive and simple implementation is the best means to an end.

A guy a while back, Bob Trinanes, was working on that very thing. Here is the archived thread --> http://archive2.avsforum.com/avs-vb/showthread.php?s=&threadid=350149

Hey! Archive2 is back!

Anyway, I think he had some schematic on the relay setup he used. Check it out.

Andy

Hi Audiodynamics,

Thanks for the info, simple is always a good plan. I have
a couple of questions;

Does it take special wiring to start the motor once again, after it has been shut off by the first reed swt ?

Will each reed switch position require a seperate relay to break the current flow for each new AR stop ?

Would someone sketch this out and display it for us ?

Do you think proxmity switches would work in the same way as a reed swt ?
-------------------------------------------

Rharkenss, do let us know what they tell you. They sent me a pdf of the instruction maual. I can email that, if somone wants it, just PM me.

John


"Does it take special wiring to start the motor once again, after it has been shut off by the first reed swt ?"

No special wiring is required. This entire control system can be built without the aid of any solid state circuitry.


"Will each reed switch position require a seperate relay to break the current flow for each new AR stop ?"

NO and YES. It depends on the current draw of the motor. If the motor draws more current than the reed switch contacts are capable of handling, then the reed switch contacts will burn out. In that case, a second relay will be necessary for current handling capability. In the worst case, two relays will be required to control one masking motor. Three position masking systems (Retracted, 4:3 and 16:9) will require three reed limit switches and may require three relays, again depending on the motor's current draw.


Do you think proxmity switches would work in the same way as a reed swt ?

There are several thypes of proximity switches. Ex: photoelectric, inductive, ultrasonic, binary, etc. The magnetic reed switch is a proximity switch in a simple form.


Here's an overview of my proposed control system:

A relay is a simple electro-mechanical switch. Applying voltage to the relay coil moves the relay contacts. The relay contacts act as a switch passing voltage from an external power supply to the masking motor, turning the motor on or off and reversing the motor's direction.

This system can be IR controlled with a Xantech IR activated relay or can simply be connected to the projector trigger. Using the PJ's trigger is simplicity in itself.


The projector trigger can be used to activate the coil of a Double Pole Double Throw relay (DPDT). In many cases, the PJ trigger may not have enough current to activate a relay coil. In this case, a solid state circuit can be used to activate the relay coil. Even easier, a special relay called a sensitive relay is designed for this purpose.

Caution: DO NOT attempt to use the PJ's trigger output to power the motor.


A. When the PJ's trigger is active, the relay can apply power to the masking motor.

B. When the masking has extended to a preset point where the magnetic reed limit switch is activated, the limit switch opens the circuit stopping the motor.

C. When the PJ's trigger is then deactivated, the contacts of the DPDT relay in it's off state can provide power to overide the limit switch, re-starting the motor and in turn moving the masking system back to it's retracted position. A second limit switch will prevent the masking from retracting too far.

D. Basically, two limit switches are required per masking panel. One limit switch sets the fully extended position and the second limit switch sets the fully retracted position. Three position masking systems (2.35 AR when retracted, 4:3 and 16:9) will require three reed limit switches (a limit switch for each position) and may require three relays, again depending on the motor's current draw.

E. Utilizing a DC motor in automating this DIY masking system will simplify things greatly. With a DC motor, the same DPDT relay which is activated by the PJ's trigger, if wired correctly, can reverse voltage polarity to the masking motor. This will reverse the motor's direction, returning the masking system to it's fully retracted position.

This concept is actually very simple to assemble, wire and implement. It should also be very reliable.

I'm happy to assist the first guinea pig who wishes to implement this proposed control system.

EDIT: The number of programmable trigger outputs your PJ or Video Scalar offers will determine whether or not you can control a three position masking system (2.35 AR when retracted, 4:3 and 16:9). You'll need two trigger outputs for three positions. If you only want a two position masking system (16:9 / 4:3) then one trigger will suffice. If you don't have enough trigger outputs, then the Xantech IR Relay block will provide complete control.

A guy a while back, Bob Trinanes, was working on that very thing. Here is the archived thread --> http://archive2.avsforum.com/avs-vb/showthread.php?s=&threadid=350149

Hey! Archive2 is back!

Anyway, I think he had some schematic on the relay setup he used. Check it out.

Andy

Good Find Andy!

I just read through Bob's DIY electric masking thread. Fantastic Design! Bob's control system is very similar to what I've proposed. I'm often amazed at the level of creativity and skill exhibited by a lot of you folks here at AVS!

I solve my client's issues by designing custom solutions for high end applications. My hats off to all you guys who tackle the tough jobs yourself and to those who have at least tried. And to the OP Scott, congratulations on the design of your great DIY masking system. The simplicity makes it that much more attractive.

My suggested automation control is a low cost, simple alternative that works seamlessly with the PJ's or video scalar's 12 vdc triggers. And it should easily be retrofittable to the OP's DIY masking system.

Got an odd question, was wondering if automobile timing tape could be used for an optical encoder to read the revolutions of a screen motor when wrapped around a spool or pulley ?

http://www.speedwaymotors.com/pl/243,5433_MSD-Timing-Tapes.html

Did you look at the "Marvomatic" post mentioned earlier, where the fellow had a home made striped tape wrapped around the roller of his Stewart screen, being read by an optical device ?

Is there some relationship in spacing or thickness of the black & white lines so that a reader can see it properly ?
Does it need to match in some way to the what the motor control board might be looking for as steps or pulses ?

Just wondering?

John

Hi Audiodynamics,

I did not see a "IR relay block" on Xantech's web site, did find a #CC12 a "remote relay module". Is the relay block called something else & do you have a part number ?

I am very interested in your approach, simple is great. I am in the planning stage, no projector or screen as yet.

I plan to use a DC motor for horiz & verticle masking on a
4' x 8' screen and to have 2.35, 1.78, 1,85 & 4:3 AR's and maual adjustment (tweeking). What type of DC motor would work best with your limit switch / relay design; a gearmotor or stepper (bipolar, unipolar) ?

Is there an RPM target recommended for the motors, is 24 RPM too slow or 80 too fast ?

Don from HTIQ recommended a torque rating of 150oz-ins (thats a tough motor to find).

In your experience, how close do the magnets need to be to the reed switches to trip them ?

John

Hey all,

In case you're having trouble seeing Bob Trinanes' old relay wiring schematics here they are. I think I"m going to go his route and use his original wiring diagram (#1). Very simple. ;)

Andy

Hi Audiodynamics,

I did not see a "IR relay block" on Xantech's web site, did find a #CC12 a "remote relay module". Is the relay block called something else & do you have a part number ?

I am very interested in your approach, simple is great. I am in the planning stage, no projector or screen as yet.

I plan to use a DC motor for horiz & verticle masking on a
4' x 8' screen and to have 2.35, 1.78, 1,85 & 4:3 AR's and maual adjustment (tweeking). What type of DC motor would work best with your limit switch / relay design; a gearmotor or stepper (bipolar, unipolar) ?

Is there an RPM target recommended for the motors, is 24 RPM too slow or 80 too fast ?

Don from HTIQ recommended a torque rating of 150oz-ins (thats a tough motor to find).

In your experience, how close do the magnets need to be to the reed switches to trip them ?

John

The Xantech CC62 Remote Relay Module (Relay Block) is the unit most suited because it has Six DPDT Relays built in.

We are a Stewart dealer. Since time is money, we prefer to sell an in the box solution for the Screen and Masking. Frequently, our clients often have unusual automation requests, requiring us to create "out of the box" solutions. The reed proximity switches and Xantech CC62 Relay Block are two of items I usually keep in my parts bins.

A DC gear motor is most suitable for your project. As for the RPM and torque requirements, it really depends on your masking design and the size of the pulleys you utilize. Larger pulleys will require less torque. Grainger sells a variety of gear motors. Since I do not build masking systems, HTIQ can provide a better answer than I.

Reed switches can be purchased from most alarm suppliers and are available in many styles. Some operate when the magnet is within an inch, while others will activate with the magnet farther away. It depends on the magnet provided. Depending upon the proximity of your cable assembly from the reed switch mounting plate, you can always experiment with the size of the permanent magnet.

Remember, my suggestion is to attach the magnets to the cable assemblies via heat shrink tubing. The reed switches are attached to semi-permanent but adjustable sliding mounting plates, allowing you to adjust the limits of your masking system. When the magnet on the cable travels to the limit switch, the motor stops, whether that position is fully retracted or anywhere along the way.

If you get the mechanicals of your masking system built and working reliably, I will be happy to assist you with its automation and control system. You'll need to figure out if 2 motors or 4 motors are required to motorize your masking panels. Also, if your PJ or VP has multiple trigger outputs for multiple AR's you don't need the Xantech. If you wish to operate your DIY masking via IR, the Xantech is a must. Depending upon your configuration, I will draw up an appropriate schematic wiring diagram for you.

Alternate Limit Switch Option:

http://www.alliedelec.com/Search/ProductDetail.asp?SKU=821-0018&SEARCH=&MPN=A%2D20GV2%2DB7%2DK&DESC=A%2D20GV2%2DB7%2DK&R=821%2D0018&sid=479D1B00DE4E17F

The Hinged Roller Lever Switches can be actuated by large (1 inch) wood or metal Beads (Round ball with a hole through the middle) that are hot glued onto the cable assembly.

Thanks Audiodynamics,

Great info & thanks for the help! Folks around are sure wonderfully helpful. I have really enjoyed this thread, a real learning experience. I am still wowed by OP Scott's wonderful design !

John

My first design used a magnet and a number of reed switches to set positions. One thing to watch out for is that if the reed switch operates for example 1 inch away from the magnet, the system will stop at a different position depending on the direction of travel. I.e. if the masking is closing it will stop 1 inch short of the magnet, and if opening the same but the opposite side of the magnet. This means you have 2 inches of difference for the same position!
In practice the distance was not as bad as an inch, but there was always a small amount of difference in position.

Ben

Thanks Audiodynamics,

I am still wowed by OP Scott's wonderful design !

Ditto

My first design used a magnet and a number of reed switches to set positions. One thing to watch out for is that if the reed switch operates for example 1 inch away from the magnet, the system will stop at a different position depending on the direction of travel. I.e. if the masking is closing it will stop 1 inch short of the magnet, and if opening the same but the opposite side of the magnet. This means you have 2 inches of difference for the same position!
In practice the distance was not as bad as an inch, but there was always a small amount of difference in position.

Ben

I use the reed switches as limits in a variety of automation projects, typically with linear actuators. They are precise enough for the job.

The Roller Lever Switches I suggested will be more precise than most magnetic reed switches. If really critical adjustment is required, the Roller Lever Switch will allow for more precise and consistent limits.

As far as the reed switches are concerned, it's all dependant on the switch assembly. Before purchasing all of the reed switches for the job, experimentation with a variety of switches is a good idea. It's important to find a switch that only activates in very close proximity.

The round or button type, flush mount reed switch that alarm installers use on doors and windows typically require very close (1/2 - 3/4 inch) proximity to open the switch contacts. And they are really cheap in bulk. These switches are mounted by drilling a hole in the top of the door for inserting the magnet. Another hole is drilled directly above the magnet in the door jamb and the reed switch is inserted. For this application, the problem with the recessed reed switch is mounting it! I suppose the button switch can be mounted in a piece of 3/4 inch plywood with slots for adjusting switch position. With flexible adjustment for both position and distance from the magnet, I believe the button type reed switch can allow accuracy within 1/4 inch tolerance. Since there will be a little image overscan onto the black borders of the screen, a limit switch with 1/4-3/4 inch tolerance is more than acceptable for this application.

http://www.alarmcontacts.com/product_info.php?cPath=22_23&products_id=34&osCsid=fec174d3f47dc8b9db048a2d98f599f2

I think I'm inclined to go with the roller switches Audiodynamics spoke about. They would eliminate any chance for any inaccuracy and are easier to install. I'm not sure if we need ones rated at 20A though :D

There isn't really any high current going through the switches so lower rated (and less expensive) ones can be used. Thanks for the link Audiodynamics!

Andy

I think I'm inclined to go with the roller switches Audiodynamics spoke about. They would eliminate any chance for any inaccuracy and are easier to install. I'm not sure if we need ones rated at 20A though :D

There isn't really any high current going through the switches so lower rated (and less expensive) ones can be used. Thanks for the link Audiodynamics!

Andy

It won't hurt to use the 20 amp switches!

You can buy the SpringAssist here: http://www.av-outlet.com/en-us/dept_511.html
At the bottom of the page. Cheap too!

Andy,

Thanks for the link.
Would we need one spring assist in each roller tube? Say I am wanting to do a 4-way masking with four 1.5" EMT pipes from HD or Lowes, would I need 4 Rollease spring assists ? Or just one per set (horiz & vert pairs) to keep tension on the pair, since I guess we'll have a figure "8" shaped cable run between the rollers to have them roll in opposite directions.
I noticed there is a Left & a Right version, it did not say if there was a difference of rotation direction or was it merely a choice as to which side of the widow shade roller tube you wanted to stuck it into ?
--------------------------------------------------------------

Audiodynamics, The round/button reed switches that are listed at the link you gave look great:
http://www.alarmcontacts.com/product...048a2d98f599f2

I did not see any mention of their power requirements, do you know what Vdc, mA they would need to be powered ?

John

Audiodynamics, The round/button reed switches that are listed at the link you gave look great:
http://www.alarmcontacts.com/product...048a2d98f599f2

I did not see any mention of their power requirements, do you know what Vdc, mA they would need to be powered ?

John

Reed switches are low current. With a reed switch, a properly rated relay will actually switch the gear motor on/off/reverse.


I'm assuming you'll use 4 motors for 4 way maskingi?

[QUOTE=Andy238;12908151]Awesome, Rich! I contacted Goelst too. The main company won't quote or sell to individuals. I asked for info on just the motor kit, 6200-00 Motor Set and the 6220 Drive Belt.

Their reply:

"I’m sorry, but I cannot quote directly to an individual. If you will let me know where you are located, I’ll refer you to a dealer. However, we normally, do not sell components to end users, only assembled products."

I'm still waiting for the dealer info.

-------------------------------------------------------------
This thread has gone quiet for a few days, don't let it die guys !

Andy,
Were you able to get pricing on the motor assembly & belt drive? I guess you were going to buy a standard curtain rod & alter it to permit the Goelst motor assembly & drive belt to operate it ? How are things going ?

Hi guys,

Ran across this simple curtain rod motor kit on eBay AU, see what you think. Seems aimed to fit standard cord draw curtain rods for less than $100 USD. The link is shown below. Maybe one of our Aussie friends has some experience with this kit as to noise level and & how well it works.

http://cgi.*********/ws/eBayISAPI.dll?ViewItem&item=280196962205&ru=http%3A%2F%2Fsearch.*********%3A80%2Fsearch%2Fsearch.dll% 3Ffrom%3DR40%26_trksid%3Dm37%26satitle%3D280196962205%26cate gory0%3D%26fvi%3D1

John,

I was thinking about just using the Goelst Motor and controller and using the belt to drive the vertical roller in Scott's design. But they didn't hve any local dealer and they didn't sound like they wanted to sell just parts anyway. I gave up that route.

My plan at the moment is to go with Bob T's design with the ir relay control board, roller switches, and DC motor. I figure that's the easiest way to motorize Scott's design since I'm only doing side masking. I'm not quite ready to build it yet but I'm getting there. Probably a couple months away.

I keep checking here though for any updates/finds.

Andy

Andy,

I ran across this NE US (Long Island City, NY) motorized drapery web site "Mechoshade", their powered drapery track is called; "Whispertrack". Their DT20 system has 5 programable stops. Some of their photos look familar, saw then under a different name some where... Ran across an article that Vutec will use their super quiet motors.

http://www.mechoshade.com/site/whispertrak/index.cfm


Ran across this UK web site (Magenta Electronics) that sells "Swish Autoglide" curtain rail parts; like pulley wheels & LH/RH pulley housings & drive belts. Did not see curtain tracks or motors for sell there and unsure if they sell overseas. Maybe Ben has some knowledge of this product. As I understand Silent Gliss bought the "Autoglide " product from Swish.

www.magenta2000.co.uk/swish/swish2.htm

Yep, you saw those pics before. That "whispertrack" looks like... a Goelst G-RAIL 6200 system! Pretty tricky, eh?

:) Hi guys, Ran across these IR relay & remote kits from this supplier, wondered if they might be useful for controlling masking motors:

www.anykits.com

4 chnl IR rmt (# H002 $16) + quad relay bd (# I006 $9.50)

8 chnl IR rmt (# H001 $16.50) + 8 chnl relay bd (# I007 $15.75)


Question, do you need one relay & one magnetic switch per AR point ?


John

Hi Scott -

I'm planning a side-masking system based on your design and I had a few questions.

Your diagram below indicates that you use a 1/2" x 2 1/2" board to provide a straight edge:

http://home.comcast.net/~scottj0007/theater/MaskingSide_TopView_1.jpg

From this photo, it look like it's an aluminum bar:

http://home.comcast.net/~scottj0007/theater/MaskingSide_Photo_04a.jpg

What material is the board made from?
If it is aluminum, did you get it from Home Depot?
How did you attach the eye screw?
How did you secure the u-channel to the frame? Double-sided tape?

Thanks!

It is a board painted black with a aluminum U channel screwed to it for straightness. The U channel for it to slid in can be screwed down just out of the way for the board to slide in.

Nate

It is a board painted black with a aluminum U channel screwed to it for straightness. The U channel for it to slid in can be screwed down just out of the way for the board to slide in.

Nate
Nate;
What material is that board made of?
____
Axel

It is a board painted black with a aluminum U channel screwed to it for straightness. The U channel for it to slid in can be screwed down just out of the way for the board to slide in.

Nate

Ahhh - my eyes are playing tricks on me!

Thanks!

Reed switches are low current. With a reed switch, a properly rated relay will actually switch the gear motor on/off/reverse.


I'm assuming you'll use 4 motors for 4 way maskingi?


Hi Audiodynamics,

Are you still reading this thread?
I was wondering which "properly rated relay" would you recommend. If not a model & brand, what would make for this type relay to provide the: on, off & reverse functions.
I plan to use 12Vdc or less motors. & to use 2 motors for a 4-way masking system.
Ran across a relay board @ Karl's Electronics that had resets inputs , had not seen that mentioned about other IR relay boards talked about here (like the "Kits-R-Us" 12 channel IR board #K142).

Thanks

John

Hi Audiodynamics,

Are you still reading this thread?
I was wondering which "properly rated relay" would you recommend. If not a model & brand, what would make for this type relay to provide the: on, off & reverse functions.
I plan to use 12Vdc or less motors. & to use 2 motors for a 4-way masking system.
Ran across a relay board @ Karl's Electronics that had resets inputs , had not seen that mentioned about other IR relay boards talked about here (like the "Kits-R-Us" 12 channel IR board #K142).

Thanks

John

John,

I would not use the IR relay system to drive the motors. I'd use it to drive the coil on a heavier relay for the motor. You can use the Bosch workhorse. These automotive relays are pretty stout. Tyco also make them. Just do a search for Bosch Automotive relay and you'll find them.

http://order.waytekwire.com/IMAGES/M37/items/75012FL.GIF


I will be driving my my masking system with an h-bridge motor driver pcb. I have all the parts, i just have to find the time.

p.s. Read this thread. It has drawings and pics of a motorized masking system.
Pics of my 4-way motorized masking system. (http://archive2.avsforum.com/avs-vb/showthread.php?t=350149&page=1&pp=30) it's in the archives.

John,

I would not use the IR relay system to drive the motors. I'd use it to drive the coil on a heavier relay for the motor. You can use the Bosch workhorse. These automotive relays are pretty stout. Tyco also make them. Just do a search for Bosch Automotive relay and you'll find them.

http://order.waytekwire.com/IMAGES/M37/items/75012FL.GIF


I will be driving my my masking system with an h-bridge motor driver pcb. I have all the parts, i just have to find the time.

p.s. Read this thread. It has drawings and pics of a motorized masking system.
Pics of my 4-way motorized masking system. (http://archive2.avsforum.com/avs-vb/showthread.php?t=350149&page=1&pp=30) it's in the archives.


Thanks "ifeliciano" for the info !

I also enjoyed that same thread from the archives. It seems that fellow is not around here any longer. Are you going to have pre-sets AR's & will you control your mtr driver bd from a microprocesser ? Keep us posted with your progress, yes with lots of photos & details - please.
A lot of good ideas have been discussed in this thread, lets keep it going...

Ran across this build by AVS member "JeffC" in the "Dedicated home theater" section, take a look at post # 35 at his find; a dual rack actuator motor for around ~$215 that will power his masks. Click on the word "here" to see the Emotion item, pretty cool !

http://www.avsforum.com/avs-vb/showthread.php?t=1025616&page=2

I found this site below the other day, a good source for manual AL & PVC curtain tracks. A person could hang their mask edge panels from bare master carriers & then pull them along by a second motorized track as AVS member Vern Dias did or by that dual rack actuator. Ideas...... :D

http://www.shop.curtaintrax.com/main.sc


John

Thanks "ifeliciano" for the info !

re you going to have pre-sets AR's & will you control your mtr driver bd from a microprocesser ? Keep us posted with your progress, yes with lots of photos & details - please.
A lot of good ideas have been discussed in this thread, lets keep it going...

Microprocessor controlled ? mmmm nah. I'm keeping it simple. Just relays transistors and optical interrupters. Maybe will look into some type of Latch.

Hey John, good find on that curtaintrax site! I really like the wheeled carriers they have. I wonder if those can be used on the top and bottom of a masking panel for smooth traveling. The bottom ones could be fastened to the panel and just ride in a proper sized J-channel. Something like rollar skates for the mask :D

I'm almost at the mask building stage. I'd guess a month or two out. I'll have to review everything we've been talking about here!

Andy

I've been following this 3d for a long time trying to steal as many ideas as possible; I have to say you folks are great!!
Did you consider to use an electric rolling courtain motor (somfy makes quite good ones) instead of the alluminiun pipe? So you'll have the motor inside the tube. Just an idea, Marco

I think we did... somewhere in here. Check post #105 by benwillcox on page 4. He mentioned it and it was talked about a bit.

My Draper Eclipse masking system uses a 120v Somfy motor....

Microprocessor controlled ? mmmm nah. I'm keeping it simple. Just relays transistors and optical interrupters. Maybe will look into some type of Latch.

Simple is always good, fewer chances for ole Murphy to visit. Been pondering the use of limit / magnetic switches (on this thread somewhere) & also Hall Effect, but snap switches & those photo interrupters look very
interesting. In that archive listing for Bob Trainas's build with the IR ctl'd 12-relay board & limit switches, there seems to be a large amount of wiring running about (maybe due to main limit switches & backups) made things look really complicated. But microprocessors & motor driver boards with programing is LOTS more so...

Andy, Glad to help. Curtaintrax has lots of good stuff. On the 84112 & 84114-P master carriers (they are 3" long &
1" high) for their ball bearing AL curtain track (Recmar brand); their metal over & underlap arms can be removed & curtain hooks directly attached to the carrier (according to an email I received from them - BTW they are very good at answering questions - remember they do curtains), that also permits for a butt type curtain (& mask for us) joint. This may allow the mask panels to be connected directly as well. Oh also, in case you don't need the 8 ft AL tracks in one piece, save some freight money & have them cut them in half before shipping (that has to be a phone order they say). Looking forward to what you come up with, are you doing a build thread ?

Tedd & airline,
Somfy tube motors, good to be reminded of them. Thanks. Their LT-30 with IR ctl, is about $150 (per side - just looked at usautomated.com ). I think Da-Lite uses them also. Some have wondered about mask GOM material sagging over time w/o a way to keep tension on the fabric once it is rolled out.

I need to go back & read from the beginning again, love OP ScottJ's theater - an inspiration for us all !

This forum, such a wonderful place ! :)

John

Somy's are nice I agree. I had one in a Draper Targa screen I had in my old HT. They are nice and quiet. One drawback to the the remote controlled Somfy's is that the IR can't be learned by other remotes (like our Prontos, Harmony's, etc).

I don't have a build thread yet. I'd like to get one going though. I just have to take the time to sift through all my pics and organize things first. I've been working on the HT for about a year and a half now. I'm doing all the work myself and it's a long road. I can see the light at the end of the tunnel though. :)

Hi AVS friends,

Ran across this interesting 4 channel UHF remote controlled relay board the other day at Carl's Electronics web site, part # HD4COMBO & sells for $37.95. Each relay can be individually selected as either momentary or latching via jumpers and there is a reset wiring option for each relay as well (for limit switches connecion). Wish they had up sized models with 8, 10 or 12 relays with resets.
Maybe someone can use this item for a build.

See the link below for details;

http://electronickits.com/remote_control/rf4.htm

I don't know if anyone is still following this thread or not, but I thought I'd post an update on my masking system now that I've had it up for over a year.

It still works flawlessly! I had to make one minor tension adjustment after a couple of months, but I haven't had to make any modifications since then. My theater is used several times each week and the vertical side masking is moved a lot. My wife and kids have no problems whatsoever moving the masking. Absolutely no fuss.

While I greatly appreciate the turn this thread took towards motorization, I have to say that I have no plans to motorize at this point. I did a lot of reading and studying on motorization and I think that I would spend more time fiddling with the automation than I spend moving the masking by hand. The manual method literally takes only a few seconds and ANYONE can figure it out. Motorization would certainly have a huge "cool" factor, but I'm afraid the hassle would be greater than what it is worth to me.

I have received numerous PM requests for additional details, which I am happy to respond to. Obviously, improvements can be made to the system, but given that this was my first shot, I couldn't be happier.

In general, I would say that masking of any sort is a huge improvement to the perceived image quality. I NEVER watch a movie without moving the masking to match the projected image ratio. In my opinion, other than proper control of lighting, masking provides the next single biggest improvement to the visual quality of the image. If you are considering a masking solution of any sort, my recommendations is DO IT. It doesn't have to be 4-way acoustically transparent like mine is. Just make it fit your needs.

- Scott

Scott I am making a rack and pinion mask system and wondering about the side masks and couldn't quite tell by the photos. Do your side panel (1/2 x 2.5 board and channel) run on the out side of your screen boarder? I think it does and wondering if the half inch plus offset is noticeable? I was going to a little extension off the top of my panels to glide just over the top of the top and bottom boarder. Not sure this makes sense put here is a rough pic. Trying to figure out if the extensions are needed/worth it

http://i258.photobucket.com/albums/hh263/jeffcjeffc/Home%20theater/masksystem.jpg


Edit this pic isn't quite accurate as the top and bottom side view are the actual fixed frame portion

Jeff,
My side panels extend over the top and bottom horizontal panels so I don't need extensions like you have shown in your drawing. There is a gap of about 3/4" between my side panels and the face of the screen, but this is not noticable at all.

You can kind of see this in the first and last pictures in post #6.

- Scott

thanks Scott

Scott,
I tried to send you a PM but your box is full.:(

Hello Scott,
I am a new member and am planning a CIH screen with verticle masking. Came across and read ALL of the posts on this thread last night! Your innovation is excellent and the contribution from the members is just fantastic.
Did some research today and came up with something that may be the answer to a lot of questions regading automation of your great design.

I propose using an Antenna Rotator like the Channel Master CM 9521A http://www.solidsignal.com/prod_display.asp?PROD=MTRTR200

The idea is to attach a large pulley in place of the antenna mast and connect it to a smaller pulley which is attatched to one of the rollers (just like in a bicycle).. A chain will work the best. The large pulley will at the most make 1 1/4 turn, but the smaller pulley can make upto 10 turns, depending on the configuration. The motor has very high torque, so force will not be an issue. The two rolers will need to be coupled in a way that the move in opposite directions (easy to do, can attach the smaller pulley to the two small pullies in the middle of the set up instead of the roller, lots of options.)

The most exciting part is that the rotator can be programmed to memorize more than 50 settings. All we need are maximum of 4 !! The display can be programmed to show different settings as eg, 240, 235 and 178 !! These settings can be accesed directly or put in the remote's presets. The remote is an IR and the codes can be learnt by any learning remote!!!!!
I just wanted to throw this out and see what the experts think. I will make some diagrams soon to illustrate everything, but it should be quite clear. A lot of ideas here are a lot more complicated than this one.
There are a lot of options regarding the materials used. eg, using rubber belts (like they use in the carriage movment of inkjet printers) instead of a chain and using aluminum tracks with nylon ball bearings, for a smoother movement etc etc. I am in the very early stages of my HT, so it will be a while before I build this contraption. In the mean time, I hope someone else (you ?) can use this idea and make a great Home Theater the coolest one!

TeeCue,

Cool idea man. Timing belts & timing pulleys could be used in place of the chain, just a thought.

John :D

Very impressive find! I've been searching the internet for more information on this unit and it looks very promising. With IR control and programmable non-volitile memory, this unit could work.

I've been looking at my screen trying to figure out how I would set up the pully system to work. I'm also wondering how accurate the memory will be, especially after rigging it up to a pully system. I'm also a little concerned about the speed. With my setup, my verticle bars have to rotate 5 times to go from 4:3 to 2.35:1. This unit takes one full minute to rotate 1 time. If I want to go from 4:3 to 2.35:1 in, say, 5 seconds, I would have to have a gearing ratio of 60 to 1. This might be a bit tricky. I'm wondering though if you took the unit apart and could access the internal motor directly, that maybe it might turn at a faster rate and require less gearing if there is a way to run directly off the internal motor.

Humm ... ... For less than $100, this might be worth buying just to tinker with to see what is possible! :D

I got the idea from the big c-band sattelite acutators. I thought of using a 24" arm to move the masking but it was very slow. Then came across the antenna rotators. Since then I have found another rotator that uses the same position sensing technology as the satelite acutators use, which is EXTREMELY accurate.http://www.tvantenna.com/products/tvreception/rotators/ROTR100.html
The sensing is not directly related to the speed of the motor, so as it uses a 17 volt supply, altering the voltage a little will help in fine tuning the speed of the drive.
As far as not using the final gear and using an internal gear for higher speed is concerned, I think that it will affect the torque of the drive. I dont think tuning the drive to obtain the correct final RPM would be that difficult.

Taking the unit apart would be difficult as they are outdoor units and have a very tight, waterproof enclosure.

TeeCue,

The positioning sensor ("Hall Sensor") on the Eagle Aspen rotator looks like just the ticket, however, I'm still having a huge problem with rotation speed on these units. The unit only turns one time before it reaches it limit, and it takes a full minute to turn one revolution. Everything else on these units looks perfect, except this one flaw. I'm no electrical engineer, but I don't think applying a higher voltage will solve the problems of the speed and the fact that it will only turn one revolution.

I did a little math on the gearing needed to acheive a 60:1 factor, which is what I think I would need to get my masking to move at an acceptable pace. The size of the gears needed does not seem practical.

You seem like you might know more about this stuff than I do. How would you get one of these rotators to move the side masking 27" in about three to five seconds?

I might be WAY off base (and maybe I'm showing my stupidity here), but my math tells me that if you tried to do this with a single gear, you would need one with a diameter of close to 8 1/2 feet.

(8 1/2 feet X 12 inches per foot * Pi = 320 inches around the gear. 320 inches / 60 seconds = 5.33 inches per second. 5.33 inches per second X 5 seconds = 26.6 inches)

Scott,

I am looking into some options regarding the speed issue. I might get one and open the motor up or use the Hall Sensor in another motor :confused:

TeeCue,

This unit has so much going for it, I figured I would order one and see if I can't figure out a solution for the gearing. I would guess that the internal motor actually runs faster than one revolution per minute and there is internal gearing that slows the unit down. Maybe the internal gearing can be bypassed. ??????

Anyway, I just now ordered one from this site:

http://www.solidsignal.tv/prod_display_print.asp?PROD=ROTR100

For only $64.99 plus $9.95 shipping, I figured I'll at least get a bit of an education on Hall Sensors, plus I might even be able to make it work. (I also have another application that I might be able to use it for if I can't make it work for the masking.)
- Scott

Scott & TeeCue,

I think gearing is the way to go, from reading on a lot of small motors, a hobby 12Vdc motor that runs 100 RPM at 12V, if you cut the power to 6 Vdc, the RPM drops 1/2 to ~60 RPM.

Looking at Tamiya hobby motors, they achieve different RPM ranges via assembly of the gears within the gearbox. The motor shown below (from the Pololu web site) has six different gear ratios depending on how you assemble & arrange the gears. Food for thought....

http://www.pololu.com/picture/view/0J232

Picture of the Tamiya gear box # 72005
http://www.pololu.com/picture/view/0J234

Source for gears: http://www.servocity.com/html/gears___sprockets.html

Have learned that one must match the "Pressure Angle" & "Pitch" values when choosing gears to mesh properly with one another.


John :D

John,

Thanks for the source for gears!

It seems to me that this whole topic of motorization should be a very simple issue. Just look at how many things in our everyday surroundings are motorized with gears and sensors... everything from car seats and windows to elevator doors to garage door openers. If a mechanical engineer with some basic knowledge of motors and gears read our posts, he would probably laugh at our fumbling around this topic.

At any rate, I think we are getting closer to a possible simple solution. If we can combine the antenna rotator motor unit with the proper gearing, maybe we can come up with a simple off-the-shelf programmable IR motorization system for less than $100. That would be cool!

Once I get the rotator unit, I will try to take it apart and post some pictures. You will have to be patient though; I am headed into my busy time of year at work (60 - 80 hour work-weeks)... so I won't have much time to work on my theater ...

John,

Thanks for the source for gears!

It seems to me that this whole topic of motorization should be a very simple issue. Just look at how many things in our everyday surroundings are motorized with gears and sensors... everything from car seats and windows to elevator doors to garage door openers. If a mechanical engineer with some basic knowledge of motors and gears read our posts, he would probably laugh at our fumbling around this topic.

At any rate, I think we are getting closer to a possible simple solution. If we can combine the antenna rotator motor unit with the proper gearing, maybe we can come up with a simple off-the-shelf programmable IR motorization system for less than $100. That would be cool!

Once I get the rotator unit, I will try to take it apart and post some pictures. You will have to be patient though; I am headed into my busy time of year at work (60 - 80 hour work-weeks)... so I won't have much time to work on my theater ...

I'm an engineering student and am not laughing at this discussion. Given the tools and "machinery" people have to make these, they are excellent.

Everything could be made easier by using stepper motors hooked directly to the rollers or maybe through a worm gear drive. Stepper motors can be had cheaply if you look around and there are many flavors of motor controllers which could use an IR input with the right inputs.

Scott, I think this is a very doable thing. John's links were very helpful, thanks John. Most of these high torque, low speed motors have a "worm gear"http://sadoun.com/Sat/Products/PowerTech/DG240%20005.jpg (the long screw like gear on the right side)
The rotation speed of this gear can be very close to what we need. If we can tap into the worm gear, it might just work. The picture is actually of a motor used to move a small sattelite dish. These are called HH motors (horizon to horizon).Their speed is 2.5 degrees per second ..even slower.

I'm an engineering student and am not laughing at this discussion. Given the tools and "machinery" people have to make these, they are excellent.

Everything could be made easier by using stepper motors hooked directly to the rollers or maybe through a worm gear drive. Stepper motors can be had cheaply if you look around and there are many flavors of motor controllers which could use an IR input with the right inputs.

Malovich,
Using stepper motors is a great idea but the problem is finding an IR controlled device that has a digital display and presets for the position of the motor and having it interface with the motor controller.
If a computer was being used for the theater then it would be easy to control the motor(s) through RS232 protocol.You could control blinds, shades, a drop down projector even a automatic setup for the anamorphic lense....the possibilities are endless.
We are trying to keep it a simple DIY project using "off the shelf" components within a reasonable price range.
Again, your idea is a great one for those who can venture into the "stepper motor control arena"

What motor do they use in their masking system?
I can hardly understand him.
Video (http://www.youtube.com/watch?v=fMRQ1ciNFz0)

What motor do they use in their masking system?
I can hardly understand him.
Video (http://www.youtube.com/watch?v=fMRQ1ciNFz0)

They are using the "Sonesse" motor made by Somfy.
http://www.usautomatedshade.com/catalog/catalog.asp?vendor=2&this_option=products&prod_type=36

I received my Eagle Aspen Antenna rotor earlier this week. I think this thing just might work! It has 99 programmable stopping points, the IR is learnable by a universal remote, it will go directly from any given programmed position to any other programmed position without having to return to "zero", it is simple to use, and it costs less than $75 delivered!

The only problem remains the speed of the rotor; however, I think this can be fixed. I took the unit apart and found that it uses a rather small motor that runs at 6500 RPM. Through a series of four reducing gears, the rotation speed is slowed to about 1 RPM at the mast. I'm pretty sure I can come up with a fairly simple modification which will bring the rotation speed up to about 26 RPM. Combining this with about a 3 or 4 inch pulley, I think I can get the masking to move at a very acceptable speed.

I have taken some pictures of the disassembled unit and will post them when I get a bit more time.

(The Somfy motors discussed above are great motors. I actually have one of them in some automated blinds in my two-story family room. The issue with the Somfy motors is that they are quite expensive. If you have the money, they would be a great solution. But then, if you have the money, you might as well buy a commercial masking system.:D)

- Scott

Thanks Scott,

Looking forward to your photos.

Hope you have a wonderful & blessed Christmas,
A Merry Christmas to all !

John :D

Scott: They are expensive but sometimes good for one off mechanical designs or prototypes - www.sdp-si.com. They have some gearing and such, you may be able to make your own gearbox if you have some way to do some precision drilling. For less precise prototyping, you may be able to use one of many types of synchronous belts or synchronous "ropes". HTH. Scott

P.S. I'm a Somfy component dealer. I had planned on desigining a masking system myself but the CineSlide got too big and took all my time. Plus I didn't want to pay for another FCC and CE certification anytime soon :). But if someone comes up with a plan using those tube motors, I can probably get you a deal on them. Merry Christmas, Scott

Thanks for the post to sdp-si.com. That is a great site.
If I were starting all over on my masking system and had a good source for Somfy motors, I think I would try to design the system around the use of tube motors. They have a LOT of advantages!


Here are the pictures of the Eagle Aspen rotor...

It is a little smaller than I expected, but that might be an advantage when trying to fit it in a small space:
http://home.comcast.net/~scottj0007/theater/rotor_01.jpg

http://home.comcast.net/~scottj0007/theater/rotor_02.jpg


Here's the unit with the bottom removed. On the inside of the casing, the gears and switches on the left are for stopping the motor once the mast rotates a full turn. This makes sense for an antenna rotor because you wouldn't want to twist the cables around the mast if it spun continuously. For our purposes, I think I will disconnect these switches.
http://home.comcast.net/~scottj0007/theater/rotor_03.jpg


Close-up of same thing as above:
http://home.comcast.net/~scottj0007/theater/rotor_04.jpg


Here, I have removed the gears that activate the switches. Getting the gears off was a bit of a pain. You need to have some retaining clip pliers. I used some small allen wrenches to gently pry the gears off of the shafts.
These gears need to be removed before you can take the mounting plate out of the housing.
http://home.comcast.net/~scottj0007/theater/rotor_05.jpg


This picture is looking up into the rotor housing. I found out the hard way that you need to keep the rotor upright when removing the internal mounting plate, otherwise all of the gears fall off the internal spindles.
http://home.comcast.net/~scottj0007/theater/rotor_06.jpg


This is the plate with motor and the gearing. You can see that the motor itself is quite small. The picture shows the gearing ratio of each gear and how the reduction to 1 RPM occurs.
http://home.comcast.net/~scottj0007/theater/rotor_07 copy.jpg


- Scott

Below are two diagrams of the last picture in my previous post. The first one shows the existing gear configuration and reduction:
http://home.comcast.net/~scottj0007/theater/rotor_gearing_01.jpg


My current thought is to change the gearing as shown in the following picture. I have not tried this yet, but in theory it should work -- and I'm hoping that it is relatively simple to accomplish...
http://home.comcast.net/~scottj0007/theater/rotor_gearing_02.jpg


I would welcome any thoughts or suggestions! I probably won't have time to actually work on doing this modification until later this coming weekend.

- Scott

Scott,

Great photos & drawings ! Cool looking piece of engineering. Looks like that might be an encoder board on the backside of the motor, so it can tell how much the shaft has turned & which direction maybe and the larger bd is the controller. Where does the IR sensor plug in ? Those limit swt inputs may come in handy sensing the limits of mask travel. Wonder how the controller bd will react when it sees light years more travel than it was expecting to see from the former one RPM gearing. Excuse me, I'm wondering all over the place.

I not even there & I am excited to see what you turn up !

Thanks for letting us look over your shoulder!

John :D:D

Great work Scott !

This motor does not have a worm gear. Your idea of connecting the first and the third gears would be the answer to we are looking for.
There are many ways to do that. The simplest would probably be to get a plastic or nylon disc or square piece (same thickness as the gears) and drill a hole in the center to accomodate the smaller gear of the first gear(B). Then, after thoroughly cleaning the surfaces, bond with JB Weld http://www.jbweld.net/products/industro.php

You will have to take the gears out and clamp everything till it cures. I dont think it is necessary but you can drill two small holes going through the three and put a cut off common pins there. The head of the pin will have to be flush. I have used the Dremel for such delicate projects. You can also use miniature machine screws and nuts but they will have to be flush on both sides.

Using the second gear(C), instead of a nylon disc, is also feasIble but grinding down the smaller gear may not be easy. Also it may be simpler not to disconnect the limit switches on the motor as they are part of the wiring and the motor may not function properly without them.

This configuration will give about 25 RPM on the rotator shaft.

I have used one of your diagrams, hope you don't mind.

This may turn out to be a great Christmas gift for the folks on the forum !!!

MERRY CHRISTMAS EVERYONE

Scott,

Great photos & drawings ! Cool looking piece of engineering. Looks like that might be an encoder board on the backside of the motor, so it can tell how much the shaft has turned & which direction maybe and the larger bd is the controller. Where does the IR sensor plug in ? Those limit swt inputs may come in handy sensing the limits of mask travel. Wonder how the controller bd will react when it sees light years more travel than it was expecting to see from the former one RPM gearing. Excuse me, I'm wondering all over the place.

I not even there & I am excited to see what you turn up !

Thanks for letting us look over your shoulder!

John :D:D

John,

The encoder is on the shaft (armature) of the motor. It will detect how many revolutions the shaft makes and has nothing to do what the final (geared) rotator RPM.

Scott,

.... Where does the IR sensor plug in ? Those limit swt inputs may come in handy sensing the limits of mask travel.
John
John, The IR sensor is actually in a separate box. This antenna rotor is designed to have the receiver in the house by the television so there is a set-top box that has the IR sensor and positioning hardware built in. The only cable going to the motor housing is a single coax. Here is a copy of the picture from the SolidSignal.TV (http://www.solidsignal.tv/) web site:
http://home.comcast.net/~scottj0007/theater/ROTR100_zoom.jpg
I probably will place the set-top receiver behind my false wall. I actually am thinking of buying three of these motors if I can get the gearing to work -- One for each side mask (although I could probably make a single one work), and one for my horizontal masking. I will put all three set-top boxes behind the false wall and hook them up to my Xantech IR control system and universal remote. I will program 5 locations on each receiver box:
Position "01" = the masking position for needed for 4:3
Position "02" = the masking position for needed for 16:9
Position "03" = the masking position for needed for 1.85:1
Position "04" = the masking position for needed for 2.35:1
Position "05" = the masking position for needed for 2.40:1
Then I can select a location and each receiver will send the information to its motor to move the masking to the proper location.

One drawback that I see when using multiple motors is that since all receivers respond to the same signal, if I press the IR remote button to manually move a motor, all three will respond. The only way to get a single motor to respond would be to turn off the receiver boxes for the other two motors. I think this is a rather minor issue though because once I program the locations for the pre-set masking ratios, I don't think I will need to make manual adjustments.

As for the limit switches, I have thought that it would be fairly easy to extend the wires and place the switches at the end points on my masking system. That way if something went wrong and the motors ran for too long, they would stop when the masking reached the end of its physical limit. (If I get the gearing all figured out, then I will look into the limit switch options when I actually install the motors.)

- Scott

P.S. I'm a Somfy component dealer. I had planned on desigining a masking system myself but the CineSlide got too big and took all my time. Plus I didn't want to pay for another FCC and CE certification anytime soon :). But if someone comes up with a plan using those tube motors, I can probably get you a deal on them. Merry Christmas, ScottScott,
Can the IR signal on the Somfy motors be "learned" by a Universal Remote?

For a future project, I want to set up my projector to drop down out of the ceiling. While I might be able to make one of these Rotor motors work, I think a tube motor might be my best option if I can find a good deal on one.

... :rolleyes:.....humm.....After I finish this masking project, maybe I'll start a new thread on a DIY projector drop-down system........

- Scott

.... Most of these high torque, low speed motors have a "worm gear"http://sadoun.com/Sat/Products/PowerTech/DG240%20005.jpg (the long screw like gear on the right side)
The rotation speed of this gear can be very close to what we need. If we can tap into the worm gear, it might just work. The picture is actually of a motor used to move a small sattelite dish. These are called HH motors (horizon to horizon).Their speed is 2.5 degrees per second ..even slower.

I was looking at the Sadoun.com web site and I think the motor they use in their system is very similar to the one used in the Rotor I have. The Sadoun motors are similarly priced to the Eagle Aspen, but do not include the IR remote and the receiver. However the Sadoun's might be an option for someone who needed a worm drive for their particular setup rather than a rotating shaft like I will have on the Eagle Aspen setup.
http://home.comcast.net/~scottj0007/theater/ROTR_DG240 copy.jpg
http://home.comcast.net/~scottj0007/theater/rotor_04.jpg

.... Your idea of connecting the first and the third gears would be the answer to we are looking for.
There are many ways to do that. The simplest would probably be to get a plastic or nylon disc or square piece (same thickness as the gears) and drill a hole in the center to accomodate the smaller gear of the first gear(B). Then, after thoroughly cleaning the surfaces, bond with JB Weld http://www.jbweld.net/products/industro.php ......
This may turn out to be a great Christmas gift for the folks on the forum !!!

Merry Christmas!

I like the idea of using a plastic or nylon disc. This might be a lot easier than grinding off the small gear. The trick will be finding a disc with the right thickness. I've never used JB Weld before, but I know a lot of people swear by it. Thanks for the suggestion.

I wonder if there will be an issue with the balance of the gear after welding it together. Since it will be spinning at 1300 RPM will there be any issues if it isn't balanced perfectly? Any thoughts?

Merry Christmas!

I like the idea of using a plastic or nylon disc. This might be a lot easier than grinding off the small gear. The trick will be finding a disc with the right thickness. I've never used JB Weld before, but I know a lot of people swear by it. Thanks for the suggestion.

I wonder if there will be an issue with the balance of the gear after welding it together. Since it will be spinning at 1300 RPM will there be any issues if it isn't balanced perfectly? Any thoughts?

There should be no problems with balance as both the gears will be on the same shaft. The bonding compound should be used in a way that it is equally spread and there is no accumulation on any side.

If the shaft of the motor was a little longer things would be much easier. One could get rid of the B and C gears and put a spacer (washer, bearing) of a smaller diameter but same thickness in their place. This would bring gear A directly in contact with gear D. I am also looking around to see if there is a longer version of the gear A available anywhere.

Can you tell me how the shaft of the gear E is embeded? Can this be taken out ? What I am thinking is that if the base of the housing of this shaft is shaved off a little then gear E will drop down to the level of gear D (C removed and B replaced by a washer HALF the the total thickness of B). Then the position of F can be adjusted with spacers or bearings, these are readily available at hobby shops.....Crazy but doable...this is a DIY forum after all...:D I will show this on one of your drawings later today.

I was looking at the Sadoun.com web site and I think the motor they use in their system is very similar to the one used in the Rotor I have. The Sadoun motors are similarly priced to the Eagle Aspen, but do not include the IR remote and the receiver. However the Sadoun's might be an option for someone who needed a worm drive for their particular setup rather than a rotating shaft like I will have on the Eagle Aspen setup.
http://home.comcast.net/~scottj0007/theater/ROTR_DG240 copy.jpg
http://home.comcast.net/~scottj0007/theater/rotor_04.jpg

I have read somewhere that a worm gear setup has an added advantage of preventing creep, acting sorta like a mechanical brake. That would be helpful to prevent spring tension in a roller from gradually pulling the mask back towards the roller. Does that make sense ?

John :D

Can you tell me how the shaft of the gear E is embeded? Can this be taken out ? What I am thinking is that if the base of the housing of this shaft is shaved off a little then gear E will drop down to the level of gear D (C removed and B replaced by a washer HALF the the total thickness of B). Then the position of F can be adjusted with spacers or bearings, these are readily available at hobby shops.....Crazy but doable...this is a DIY forum after all...:D I will show this on one of your drawings later today.
The shaft of gear E is embeded into the metal base. I can't budge it with my fingers. I'm a little reluctant to use pliers on it yet because I don't want to damage it.

I have read somewhere that a worm gear setup has an added advantage of preventing creep, acting sorta like a mechanical brake. That would be helpful to prevent spring tension in a roller from gradually pulling the mask back towards the roller. Does that make sense ?
John :DJohn,
Yes that makes a lot of sense -- Very good point. That would definitely be a factor for anyone with masking that is tensioned with spring rollers. In my case, there is no spring tension so it is not a concern. Any system with tension would need some type of breaking mechanism on the motor to prevent creepage.

I have read somewhere that a worm gear setup has an added advantage of preventing creep, acting sorta like a mechanical brake. That would be helpful to prevent spring tension in a roller from gradually pulling the mask back towards the roller. Does that make sense ?

John :D

You are absolutely correct. That is the biggest advantage of worm drives. The most common use that we see is in car jacks (a variant of the worm concept), even the weight of the vehicle does not make the worm gear turn backwards.

In Scott's set up, if the springs are not pulling the masking back currently, then it would not be a problem. The gears definitely have a braking / holding effect and should do just fine. On the other hand, I would not recommend using a tubular gear drive motor to move a projector up and down !!!

The shaft of gear E is embeded into the metal base. I can't budge it with my fingers. I'm a little reluctant to use pliers on it yet because I don't want to damage it.

OK, lets not mess around with that. I think the bonding would be just fine. Have to be careful that no compound gets on to the gear teeth and the inner bore.

If you have a universal remote that can be programmed with a pause or delay between commands, then it would be very easy to control two or more motors with one remote control, all the motors responding independantly of each other.

The limit switch idea to control a run away motor is a good one.

I stand to correct my self regarding an earlier post regarding keeping the internal limit switches. Those switches will have to be bypassed as they will stop / reverse the motor after the first full revolution of the rotor. We need the rotor to go more than that!!

On the other hand, bypassing the switches may interfere with the calibration of the unit which can be very problematic.

Can you PM me the owners manual and the schematic if available.........Getting complicated !!!!!!!!

Scott,

The gear (A) on the motor is also called a Pinion Gear. A lot of local hobby shops that sell RC cars, planes or helicopters sell these. If you can find one that is long enough to engage gear D, then the problem is solved.

http://www.rcdude.com/servlet/the-Pinion-Gears/Categories

What do you think about the concerns I raised in post # 207.

More wonderings...

Here's a link to ServoCity's shaft couplers to lengthen the motor shaft, but you might have to move the motor further away from the bottom plate (on stand offs?) so the coupler won't rub on the lower gear. The second link is for shafts, they also have pinions. Not sure if the motor's shaft is metric or inch std. I am sure other places sell them as well (like the sdp-si.com place).

http://servocity.com/html/pinion_gears.html

http://servocity.com/html/shafts__rod___tubing.html

SDP-SI has long shafted pinions that might work with the coupler, once the motor has been moved further away. See Inch products, then gears, then Spur gears, then Metal-pinion shafts, could not grab a direct link.

Those two factors when meshing gears pop up here, that Pitch & Pressure Angle values must match. A store that sells gearing should be able to measure that. But, using the pinion you already have would alieve those issues once mounted on a longer shaft.

John :D

If you have a universal remote that can be programmed with a pause or delay between commands, then it would be very easy to control two or more motors with one remote control, all the motors responding independantly of each other. I have a Logitech Harmony One. If we get the motor gearing resolved and when I get to the point of programming the control, we'll talk more about this.

The limit switch idea to control a run away motor is a good one.

I stand to correct my self regarding an earlier post regarding keeping the internal limit switches. Those switches will have to be bypassed as they will stop / reverse the motor after the first full revolution of the rotor. We need the rotor to go more than that!!

On the other hand, bypassing the switches may interfere with the calibration of the unit which can be very problematic.I've wondered about this issue of the calibration. The unit does have a "resynchronization" process that you can run if it gets out of calibration. I've wondered if this uses the limit switches to find the "zero" point and reset itself. I'll play with this a bit more once the gearing problem is resolved. I'm sure we can come up with a solution to the calibration issue.

Can you PM me the owners manual and the schematic if available.........Getting complicated !!!!!!!!I'll need scan it to a PDF file. I don't have a scanner available now, but I'll get it to you in the next couple of days.

The gear (A) on the motor is also called a Pinion Gear. A lot of local hobby shops that sell RC cars, planes or helicopters sell these. If you can find one that is long enough to engage gear D, then the problem is solved.
http://www.rcdude.com/servlet/the-Pinion-Gears/Categories
Here's a link to ServoCity's shaft couplers to lengthen the motor shaft, but you might have to move the motor further away from the bottom plate (on stand offs?) so the coupler won't rub on the lower gear. The second link is for shafts, they also have pinions. Not sure if the motor's shaft is metric or inch std. I am sure other places sell them as well (like the sdp-si.com place). http://servocity.com/html/pinion_gears.html http://servocity.com/html/shafts__rod___tubing.html SDP-SI has long shafted pinions that might work with the coupler, once the motor has been moved further away. See Inch products, then gears, then Spur gears, then Metal-pinion shafts, could not grab a direct link.

Those two factors when meshing gears pop up here, that Pitch & Pressure Angle values must match. A store that sells gearing should be able to measure that. But, using the pinion you already have would alieve those issues once mounted on a longer shaft.JohnI like the idea of extending the pinion gear. If I can find the right coupler and extension I think this will be a quick and easy solution to the gearing issue. I have a hobby store close to me that I will stop by today to see if they can help with this. Maybe they can help me with the pitch and pressure angles, as well as the correct shaft diameter.

I still believe we can come up with a simple to implement modification for this rotor that will make it an excellent option for anyone who wants to motorize a DIY masking system. I think we are getting closer.

Yes, keeping the pinion gear you already have would be the best solution, no need to hunt & match another gear. But would be nice to know (PA & Pitch), in case other gearing might be needed. Wish the coupler had a thinned wall thickness... maybe there are thinner ones from other vendors. Good luck on your search today.

John :D

Scott,

What happens if gear B is turned upside down and C is removed? This way B and D are against each other, easier to bond, without any spacer. Do all the gears engage?

What happens if gear B is turned upside down and C is removed? This way B and D are against each other, easier to bond, without any spacer. Do all the gears engage?The gears have a raised hub in the center which causes the gears not to touch each other except at the center hub.

I've found a possible easy solution though. I found an extended pinion gear that is about twice the length of the original pinion gear. You can see it here (http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJHU0&P=7). I'm hoping it is long enought to extend to gear D. If so, this problem is solved! I've order one and it will take about a week to get here.
- Scott

The gears have a raised hub in the center which causes the gears not to touch each other except at the center hub.

I've found a possible easy solution though. I found an extended pinion gear that is about twice the length of the original pinion gear. You can see it here (http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJHU0&P=7). I'm hoping it is long enought to extend to gear D. If so, this problem is solved! I've order one and it will take about a week to get here.
- Scott

Excellent !!

I am looking at some other options also. Can you take a picture of the gears, looking at them from the top?

I am looking at some other options also. Can you take a picture of the gears, looking at them from the top?http://home.comcast.net/~scottj0007/theater/roto_gears_top.jpg

Found a couple more shaft coupler sources, if you need them. Was the hobby shop any help ? What did the pinion shaft diameter end up being ?

John

http://home.comcast.net/~scottj0007/theater/roto_gears_top.jpg

Thanks Scott.

Now can you please measure the diameter of both gears (inner and outer) on each of Dand E. I have a pretty acurate count of the teeth on them but an actual count will be helpful. I am trying to calculate the pitch of the gears. I have a whole different approach in mind but I need that data to see if it will work. Should have gotten a unit of my own to tinker with :(

John,
The hobby store wasn't a lot of help. However, to their defense, they had about two dozen police officers storm their store with guns drawn about 15 minutes before I arrived. The police apprehended one of their customers who had been reported to have been pointing a gun at people on the street. Everyone was a bit shaken up, so I can understand why they didn't consider my questions as top priority.

Teecue,
I don't have a set of precision calipers, but as nearly as I can measure, I believe the measurements are as follows:

Pinion Gear "A" = 2.5mm shaft, 11 teeth, 7mm outside diameter, 5.5mm pitch diameter, .5 mod

Gears "B", "C", and "D" large gear = 3 mm shaft, 55 teeth, 28.5mm outside diameter, 27.5 pitch diameter, .5 mod

Gears "B", "C", and "D" small gear = 3mm shaft, 12 teeth, 7mm outside diameter, 6mm pitch diameter, .5mod

Gear "E" large gear = 5mm shaft, 80 teeth, 41mm outside diameter, 40mm pitch diameter, .5 mod

Gear "E" small gear = 5mm shaft, 11 teeth, 13mm outside diameter, 11mm pitch diameter, 1.0 mod

Gear "F" (inside housing, attached to mast) = 17mm shaft, 65 teeth, 67mm outside diameter, 65mm pitch diameter, 1.0 mod

- Scott

http://home.comcast.net/~scottj0007/theater/MaskingSide_Photo_04a.jpg
Note the back Gorilla masking tape. I had to use this because as the fabric rolls onto the pipe, the diameter gets bigger and the fabric begins to roll up faster. The cable has to roll onto the pipe at the same rate as the fabric or else it starts to bind. This is not an elegant solution, but it works. I wrapped several layers of tape where the cable starts on the pipe and then there are fewer and fewer as the cable wraps down the pipe, it was a trial and error effort that took some time to get right, but it works very smoothly now.


Scott,

Could fabricating and installing a pulley alleviate the cable binding issue you encountered ?

Could fabricating and installing a pulley alleviate the cable binding issue you encountered ?My gorilla tape solution to the binding problem is probably one of the ugliest things about my masking system. I'm a little embarrassed that I couldn't come up with something better :o. I suppose a pulley could solve the problem if it were set up in a way to change the rate at which the cable wrapped onto the pulley so that it always matched the rate at which the fabric wrapped onto the vertical bar.

The problem is that as the fabric wraps onto the vertical bar, the diameter gets larger and larger. As the diameter increases, a single revolution of the bar wraps up more fabric. In other words, when there is a small amount of fabric on the bar, a single revolution of the bar opens the masking less distance than when there is a lot of fabric on the bar. Since the cable is attached to the leading edge of the masking, it has to travel at exactly the same rate as the fabric that wraps onto the bar. If you came up with a pulley that could compensate for this, it would work.

My gorilla tape solution to the binding problem is probably one of the ugliest things about my masking system. I'm a little embarrassed that I couldn't come up with something better :o. I suppose a pulley could solve the problem if it were set up in a way to change the rate at which the cable wrapped onto the pulley so that it always matched the rate at which the fabric wrapped onto the vertical bar.

The problem is that as the fabric wraps onto the vertical bar, the diameter gets larger and larger. As the diameter increases, a single revolution of the bar wraps up more fabric. In other words, when there is a small amount of fabric on the bar, a single revolution of the bar opens the masking less distance than when there is a lot of fabric on the bar. Since the cable is attached to the leading edge of the masking, it has to travel at exactly the same rate as the fabric that wraps onto the bar. If you came up with a pulley that could compensate for this, it would work.

Just a thought, but instead of attaching the cable directly to the bar, what about using a ~1.5" wide strip of the same masking fabric between the cable and bar? That way, as the masking is wrapping around the bar, the fabric strip-cable will also change diamater at exactly the same rate. You could put clamp-on collars on the bar as a channel to prevent the strip from traveling up and down.

Just a thought, but instead of attaching the cable directly to the bar, what about using a ~1.5" wide strip of the same masking fabric between the cable and bar? That way, as the masking is wrapping around the bar, the fabric strip-cable will also change diamater at exactly the same rate. You could put clamp-on collars on the bar as a channel to prevent the strip from traveling up and down.
Great idea! I hadn't thought of that. If I ever have to replace the gorilla tape or cable, I'm going to try this.

Great idea! I hadn't thought of that. If I ever have to replace the gorilla tape or cable, I'm going to try this.
Wait a minute... I think this won't work... It is in opposite directions.

When there is a lot of fabric wrapped on the bar, there is the least amount of cable wrapped on the bar. Using a ~1.5" piece of fabric attached to the cable would have the least amount on the bar at the opposite time it is needed. In other words, when there is a small amount of cable wrapped on the bar, it needs to be at its greatest diameter. As the masking fabric rolls off the bar and the cable rolls onto the bar, the diameter needs to decrease.

Does this make sense?

Wait a minute... I think this won't work... It is in opposite directions.

When there is a lot of fabric wrapped on the bar, there is the least amount of cable wrapped on the bar. Using a ~1.5" piece of fabric attached to the cable would have the least amount on the bar at the opposite time it is needed. In other words, when there is a small amount of cable wrapped on the bar, it needs to be at its greatest diameter. As the masking fabric rolls off the bar and the cable rolls onto the bar, the diameter needs to decrease.

Does this make sense?

I think it'll work...

Assume the masking is fully rolled (wrapped) around the bar; i.e. in fully open 2.40 position. The fabric strip will be fully extended (unrolled/wrapped). As you pull the masking out, the masking roll gets smaller, but then the strip roll gets larger since it's wrapping in the opposite direction. Since the material that is unrolling (masking) is the same thickness as the material that is unrolling (strip), the diameters of both rolls change at the same rate so that the tension remains constant.

It may help to think of it as a belt unrolling on one bar then rolling onto another, except in this case the belt is folded over so that a single bar can be used to unroll and roll at the same time.

Not sure if what I'm saying is very clear or actually makes sense. Maybe I'll try to come up with some sketches if I can figure out how.

I think it'll work...

It may help to think of it as a belt unrolling on one bar then rolling onto another, except in this case the belt is folded over so that a single bar can be used to unroll and roll at the same time.
Maybe I am thinking about this incorrectly, but I like your belt analogy. See the following diagram...
http://home.comcast.net/~scottj0007/theater/gorilla_issue.jpg

If each bar turns exactly one revolution, there will be slack in the line because 6.28" of belt would roll off of the left bar but only 4.71" of belt would roll onto the right bar.

Once half of the belt were rolled off of the left bar and onto the right bar, then the right bar would start getting larger than the left bar. At this point the right bar would start taking up the slack until the entire belt was rolled off of the left bar. In the end it would equal out, but the problem is that there is slack in the belt at all times except at the beginning and at the end.

My gorilla tape solution to the binding problem is probably one of the ugliest things about my masking system. I'm a little embarrassed that I couldn't come up with something better :o. I suppose a pulley could solve the problem if it were set up in a way to change the rate at which the cable wrapped onto the pulley so that it always matched the rate at which the fabric wrapped onto the vertical bar.

The problem is that as the fabric wraps onto the vertical bar, the diameter gets larger and larger. As the diameter increases, a single revolution of the bar wraps up more fabric. In other words, when there is a small amount of fabric on the bar, a single revolution of the bar opens the masking less distance than when there is a lot of fabric on the bar. Since the cable is attached to the leading edge of the masking, it has to travel at exactly the same rate as the fabric that wraps onto the bar. If you came up with a pulley that could compensate for this, it would work.


I see what you mean. I'll have a friend crank up his mill and make me a few like in the image. Larger and smaller part of pulley will match the diameter of the rolled and unrolled fabric.

http://img401.imageshack.us/img401/8738/pulleybz2.gif

Nice pulley drawing! I think that would work very well.
-- Now, if we all had friends with mills that could do that ...:cool:

:D:D:D...I'm going to ask. It doesn't mean he'll do it..Or I can put some wood on a lathe and try to make something.

Maybe I am thinking about this incorrectly, but I like your belt analogy. See the following diagram...
http://home.comcast.net/~scottj0007/theater/gorilla_issue.jpg

If each bar turns exactly one revolution, there will be slack in the line because 6.28" of belt would roll off of the left bar but only 4.71" of belt would roll onto the right bar.

Once half of the belt were rolled off of the left bar and onto the right bar, then the right bar would start getting larger than the left bar. At this point the right bar would start taking up the slack until the entire belt was rolled off of the left bar. In the end it would equal out, but the problem is that there is slack in the belt at all times except at the beginning and at the end.

You're probably right, but I'd like to work out some numbers. Can you tell me how many layers are wrapped around the bar when the masking is fully opened? And how thick is it?

You're probably right, but I'd like to work out some numbers. Can you tell me how many layers are wrapped around the bar when the masking is fully opened? And how thick is it?My vertical bars are 1.5" in diameter. When the masking is fully open at 2.4:1 there are 6 layers of fabric wrapped around the bar. The bar with 6 wraps of fabric is about 2" in diameter.

When the masking is moved from 2.4:1 to 4:3 it travels about 26.5 inches and the bar rotates slightly less than 5 times (1 full wrap of fabric always remains on the bar).

My vertical bars are 1.5" in diameter. When the masking is fully open at 2.4:1 there are 6 layers of fabric wrapped around the bar. The bar with 6 wraps of fabric is about 2" in diameter.

When the masking is moved from 2.4:1 to 4:3 it travels about 26.5 inches and the bar rotates slightly less than 5 times (1 full wrap of fabric always remains on the bar).

ilsiu,
Here is a suggestion. Make the pulley, around which the string turns back, FREELY MOVABLE and have a constant tension on it through a weight. This way the horizontal movement of the pulley will compensate for any changes in the diameter of the tube. I have shown this by ruining another one of Scott's photos:o:o:o

My vertical bars are 1.5" in diameter. When the masking is fully open at 2.4:1 there are 6 layers of fabric wrapped around the bar. The bar with 6 wraps of fabric is about 2" in diameter.

When the masking is moved from 2.4:1 to 4:3 it travels about 26.5 inches and the bar rotates slightly less than 5 times (1 full wrap of fabric always remains on the bar).

Yeah - I see what you mean now.

In your current system, it looks like you use the gorilla tape to build up the diameter for the cable axle to take up the initial slack, but it looks like the diameter it fixed, so as you continue unwind the masking and wind up the cable, the tension increases on the cable. This is probably ok since you've got a spring in series with the cable to allow for variable tension.

I think the variable diameter pulley that ifeliciano came up with is the best solution, although it would be nice to have a spiral groove for the cable to ride in so that it doesn't slip during rolling. But that's even harder (more expensive) to machine.

Scott,

Please check your PM box for a message regarding a possible new approach to the gear problems.

The gear modification is finished! I think this just might work.

The mast now rotates at 25 RPM. The only issue is that the torque of the motor has been significantly reduced due to the gearing change. Any masking that you want to move will need to be fully counter balanced so that the motor does not have to lift or move anything too heavy.


Here is the finished picture...
http://home.comcast.net/~scottj0007/theater/roto_gear_mod_finished.jpg

I bought several different gears from TowerHobbies.com (http://www.towerhobbies.com/). Any of them will work, but I recommend the 2.3mm "Venom" gears.
http://home.comcast.net/~scottj0007/theater/roto_gear_mod_02.jpg

http://home.comcast.net/~scottj0007/theater/roto_gear_mod_03.jpg

http://home.comcast.net/~scottj0007/theater/roto_gear_mod_04.jpg


Original pinion gear in the middle, next to the new Venom 2.3mm gears. The package of Venom gears comes with one 11 tooth and one 12 tooth gear.
http://home.comcast.net/~scottj0007/theater/roto_gear_mod_05.jpg


Here is a picture of the shafts without any gears...
http://home.comcast.net/~scottj0007/theater/roto_gear_mod_06.jpg


The gear is 2.3mm but the motor shaft is 2.5mm. I had to drill the pinion gear out with a 3/32" carbide drill bit. You have to rotate the bit around to make the bore hole a little bigger than the 3/32" drill bit.
http://home.comcast.net/~scottj0007/theater/roto_gear_mod_07.jpg


I used the second "extra" pinion gear with 12 teeth as a spacer. The shaft that it goes on is 3mm. I drilled out the gear with a 3/32" bit, then a 7/64" bit, and finished with a 1/8" bit. This makes the pinion gear bore large enough to fit on the shaft.
http://home.comcast.net/~scottj0007/theater/roto_gear_mod_08.jpg

http://home.comcast.net/~scottj0007/theater/roto_gear_mod_09.jpg


Here, the newly bored out gears are installed on the shafts. Note that the "spacer" gear is too tall.
http://home.comcast.net/~scottj0007/theater/roto_gear_mod_10.jpg


I ground down the spacer gear just a little bit. Take enough off that the other gears look like they align as close as possible when you put them on.
http://home.comcast.net/~scottj0007/theater/roto_gear_mod_11.jpg

http://home.comcast.net/~scottj0007/theater/roto_gear_mod_12.jpg

http://home.comcast.net/~scottj0007/theater/roto_gear_mod_13.jpg

http://home.comcast.net/~scottj0007/theater/roto_gear_mod_finished.jpg


I have some more pictures to post of the limit switches and how they work. I'll try to post them this coming weekend.

The reduced torque may be an issue for some people who need more power for their masking system. TeeCue sent me an idea that might solve this. His idea was to find a gear motor with a faster RPM and more power. Don't make any modifications to the rotator motor other than to connect the power leads for the new motor onto the positive and negative terminals on the back of the rotator motor. This way you could use all of the capabilities of the rotator (IR, nonvolitile memory, preset locations, etc.) but drive a more powerful motor. You would connect the new gear motor to your masking system.

I thought this was a great idea and might be a very good alternative solution.

TeeCue, please elaborate if you wish...

- Scott

Great work Scott, hope it works for you.

For those who are interested here is the other option I discussed with Scott.

How about we leave the whole unit as it is , take a PARALLEL connection from the motor and connect a gear motor
http://servocity.com/html/3-12v_gear_motors.html and use it. There are some other motors on this site also.
So anytime a signal goes to the rotor motor, it will also drive the gear motor for the same length of time. Then if the rotor reveses direction so will the gear motor. For this to work, you will have to identify the (+) and (-) terminals of the rotor motor. You should be able to identify the connections on the Hall Sensor board.

Well TeeCue, You just got me too interested in the gear motor idea...


I ordered two more Eagle Aspen Rotators and I also ordered two of these today:

http://home.comcast.net/~scottj0007/theater/Dayton_1L477.jpg

This is a Dayton Model #1L477 (here) (http://www.grainger.com/Grainger/items/1L477). This motor is actually a discontinued model that I found on E-bay for $38. The new Dayton model is the 1LPV5 (here) (http://www.grainger.com/Grainger/items/1LPV5) and sells for $148. I think this motor will be perfect. It has a lot of torque and is rated at 26 RPM. Now I'll just have to figure out the details of hooking it up to the rotator.

I still think that the modified Rotator motor is going to work fine. In fact, I will probably use the modified rotator without the new gear motor for my primary side masking. There is almost no load on my masking system for the side masking so I don't think I will need any additional power.

However, I'm still thinking about a concealed ceiling lift for my projector, and I know I will want more power for that application. I am also thinking I may want more power for my top and bottom masking.

Two weeks until delivery...
- Scott

I was going to suggest Pittman Gearmotors, but at $200+ might be cost prohibitive and Micro-Mo might not have enough torque.

Im going to try these motors. The black one is a very high torque dc servo actuator with and encoder, spins 30 rpm @ 24vdc. I don't have torque specs but it it very strong. The other motor is a no name Taiwanese gear motor with fairly good torque and spins 10 rpm @ 24vdc..

http://img301.imageshack.us/img301/250/p1080043sh0.jpg (http://imageshack.us)

Well TeeCue, You just got me too interested in the gear motor idea...


I ordered two more Eagle Aspen Rotators and I also ordered two of these today:

http://home.comcast.net/~scottj0007/theater/Dayton_1L477.jpg

This is a Dayton Model #1L477 (here) (http://www.grainger.com/Grainger/items/1L477). This motor is actually a discontinued model that I found on E-bay for $38. The new Dayton model is the 1LPV5 (here) (http://www.grainger.com/Grainger/items/1LPV5) and sells for $148. I think this motor will be perfect. It has a lot of torque and is rated at 26 RPM. Now I'll just have to figure out the details of hooking it up to the rotator.

I still think that the modified Rotator motor is going to work fine. In fact, I will probably use the modified rotator without the new gear motor for my primary side masking. There is almost no load on my masking system for the side masking so I don't think I will need any additional power.

However, I'm still thinking about a concealed ceiling lift for my projector, and I know I will want more power for that application. I am also thinking I may want more power for my top and bottom masking.

Two weeks until delivery...
- Scott

One can never have enough automation:D:D

You can even use heavy duty motors, with their own seperate power supply. This can be accomplished by using two sets of relays (one for forward and one for reverse)and just connecting the relays to the rotor motor. This way there won't be an overdraw of current from the control board or any issues with the gearmotor voltage. The new gearmotor will be totally isolated from the rotor unit.

For your projector project, I would reccomend a motor with a worm gear in it, so that there is no reversal of drive (under the projector weight) when the power is shut off.

Some of the most powerfull and inexpensive worm gear motors out there are the ones used in the power windows of automobiles http://skycraftsurplus.com/index.asp?PageAction=VIEWPROD&ProdID=814

Another motor that seems very powerfull is one from WONDERMOTOR http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220330640601&ih=012&category=71400&ssPageName=WDVW&rd=1

All you need to use these motors is a seperate power supply and the relay setup.

You can even use heavy duty motors, with their own seperate power supply. This can be accomplished by using two sets of relays (one for forward and one for reverse)and just connecting the relays to the rotor motor ... All you need to use these motors is a seperate power supply and the relay setup.Can you give some specifics on how to do this?

...Im going to try these motors. The black one is a very high torque dc servo actuator with and encoder, spins 30 rpm @ 24vdc. I don't have torque specs but it it very strong. The other motor is a no name Taiwanese gear motor with fairly good torque and spins 10 rpm @ 24vdc. Cool. Did you already get one of the rotators? I'd be interested to hear anything you learn about connecting the gear motor to the rotator controller.

Scott,

I will draw some schematics soon.

Cool. Did you already get one of the rotators? I'd be interested to hear anything you learn about connecting the gear motor to the rotator controller.

Nope..I was thinking about going a different way. I have an IR relay board and some high current relays. I can make it simple like Bob Triannes system or... One of the EE's (PhD) at my work is also a professor at a local college. I talked to him about a "project" for his class. A simple motor driver circuit that would drive a motor to X amount of set positions and able to jog for fine adjustments.

Although my chances are slim, I really do pray option 2 pans out...:)

Scott,

Here is the relay scehmatic. I am no electrical engineer ( just a hobby) but this should work. Any input from an elctrical engineer is welcome.

I have used two DPDT (double pole double throw relays). When a normal signal is sent to the rotator motor, relay #1 is energized and the gear motor gets normal polarity power (+ to + and - to -). When the rotation of the rotator is reversed by the controller, relay # 2 is energized and the polarity of the gear motor is revrsed also (+ to - and - to +), making it rotate in the reverse direction also. This is the mode shown in the schematic.

Looks complicated but it is very simple and inexpensive to build. More on this later.

Looks good and simple which is very important in case of needed troubleshooting. Hell I might order one of those rotators, but I'm waiting on the professor to answer me.:)

More ramblings on stuff & ideas;

The "Kits-R-Us" (model # K180V3 for $38 assembled) UHF rmt ctl 4 relay board that has jumper selectable momentary or latching function (latching is what we need I think) as well as a reset connection for each relay. The description says it allows for a limit switch to be connected to each relay for reseting. The link below is to Carl's Electronics web page. (There is also a two relay version board. But the ten relay Kits-R-Us board kit has NO reset or jumper selectable relay function ability-- that is a real shame !)

I have wondered if one could use limit switches or Hall Effect swts (attached in an adjustable manner onto a rail) to stop the motor at different points (Presets) for different AR positions ? The board has 5V output for swts. You know; press rmt ctl button "One" and the motor starts & drives to limit switch "One" position. Limit swt "One" resets relay "One" on the K180V3 relay board above & motor stops the mask panel in the right spot we've chosen. Have not gotten around to buying this stuff to experiment as yet & constructing such a thing). Guess you might need a second set of limit swts at full open & close to trip another relay to change motor direction or can you piggy back off one set ? I am no electronics guy.

Of course you would need full open & full close limit swts (guess you would need another relay to change motor direction) plus swts for each AR position. Maybe one could use two boards & hack the two remotes and place the little TX boards in a rmt ctl sized project box. That would give; full open, full close & six possible AR points. Not sure how
forward & backward adjustment buttons would be wired in...?

http://www.electronickits.com/remote_control/rf4.htm

This link is to "Kits-R-Us" web site photo of the board;
http://kitsrus.com/jpg/k180.jpg

EDIT: Just noticed the relays were different colors in the two links above, unsure why, guess they changed components for some reason.

Somewhere in that old Bob Trianas thread in the AVS Archives someone mentioned using Comparator type IC's & "logic table" to build a control board, don't think they ever finished that idea. Hey the simpler the better !

Picaxe makes a very simple $15 combo motor driver & microprocessor board, the "Picaxe-08 Motor Driver Board". Board runs at 6 Vdc MAX, but your loads, motor & otherwise, should not total more than 800 mA @ 4.5 volts
Guess one would have to really watch the stall current of the motor in use. Then their is the programming and will that small IC hold enough code to do what we want? Not sure how far 80 lines & 256 bytes of memory will take you
in programing...

See link to HVW Tech web page for this little jewel;
http://www.hvwtech.com/products_view.asp?ProductID=677

Info on the Picaxe 08M 8-pin IC: http://www.hvwtech.com/products_view.asp?ProductID=515

Man, I hope the rmt ctl antenna motors ScottJ007 & TeeCee are working on will make a great cheap solution !
ifeliciano let us know what you coworker / prof says and how your relay board goes also!

John (I'll hush for now... man this post got long winded, oh yeah I was hushing wasn't I ...)

Scott,

Here is the relay scehmatic. I am no electrical engineer ( just a hobby) but this should work. Any input from an elctrical engineer is welcome.

I have used two DPDT (double pole double throw relays). When a normal signal is sent to the rotator motor, relay #1 is energized and the gear motor gets normal polarity power (+ to + and - to -). When the rotation of the rotator is reversed by the controller, relay # 2 is energized and the polarity of the gear motor is revrsed also (+ to - and - to +), making it rotate in the reverse direction also. This is the mode shown in the schematic.

Looks complicated but it is very simple and inexpensive to build. More on this later.
I think I understand. Would diodes like this (http://www.radioshack.com/product/index.jsp?productId=2062589) and relays like this (http://www.radioshack.com/product/index.jsp?productId=2049722) from RadioShack work? Or would you recommend something different?

Scott,
Yes, the diodes are the exact ones. The relay has a resitance of 160 ohms. Will have to do some calculations regarding putting them in SERIES instead of PARALLEL, but they can be used. The two little black square boxes at one end of the control board, next to where the white cable is coming off, are the relays on the system (I guess you knew that !!). You can probably hear them click when the motor turns on. If you trace back the +ve and the -ve wires from the back of the motor they should end up connected to these relays. You will have to cut one of these cables to get a SERIES connection. On the other hand if we can find a DPDT relay with a higher resistance, we may be able to get a parrallel connection directly off of the motor board. If the motor power is coming from the relay connections and there are no other electronics involved in that circuit then a SERIES versus PARALLEL connection may not make a big difference.

John, your ideas are very interesting. It is a different way of controlling the motors that will need a lot of modifications for individual DIY HT enthusiasts. If the rotator project works out it will be very easy to integrate into any system. Very good links though, thanks.

Here is a link to All Electronics web page for DPDT relays & they have eleven choices, 6 with > 270 ohms. See if one of these is useful....

http://www.allelectronics.com/index.php?page=search&search_query=DPDT+relay&x=23&y=11

John

Here is a link to All Electronics web page for DPDT relays & they have eleven choices, 6 with > 270 ohms. See if one of these is useful....

http://www.allelectronics.com/index.php?page=search&search_query=DPDT+relay&x=23&y=11

John

John,
I saw those relays.They look promising.

Thanks

Newark Electronics has thousands of relays. My problem is I don't know enough about electronics to know what we are specifically looking for.
Here's a link to several with a resistance of 360ohm (http://www.newark.com/jsp/search/browse.jsp;jsessionid=YJYIWIV34DAEUCXDUZ1G2WQ?N=1002190+2973 24+293748+272952&_requestid=224232).

On the back of the motor, underneath the hall sensor, I do have access to the positive and negative terminals on the back of the motor. Could I solder a wire to each of these terminals to get a parrallel connection? Or are you thinking that it would be better to find a connection directly off of the control board?