4-Way Acoustically Transparent Masking - Page 4 - AVS Forum
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post #91 of 837 Old 01-16-2008, 05:33 PM
 
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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
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post #92 of 837 Old 01-17-2008, 03:48 AM - Thread Starter
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I’ve been away a couple of days. Great discussions!

Quote:
Originally Posted by camarillo_cinema View Post

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.

Quote:
Originally Posted by camarillo_cinema View Post

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?

Quote:
Originally Posted by HDGTX View Post

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.

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Originally Posted by Freddie View Post

…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.

Quote:
Originally Posted by Axel View Post

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.
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post #93 of 837 Old 01-17-2008, 12:14 PM
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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
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post #94 of 837 Old 01-17-2008, 06:24 PM - Thread Starter
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Quote:
Originally Posted by Freddie View Post

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

Keith, I sent you a PM.
- Scott
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post #95 of 837 Old 01-17-2008, 06:39 PM
 
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Quote:
Originally Posted by Freddie View Post


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

Keith

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

Don
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post #96 of 837 Old 01-18-2008, 07:26 AM
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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!

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?

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-bi...LLER_KIT_.html
There a bunch more contollers out there too.

Encoder: http://www.alltronics.com/cgi-bin/it...ical%2Dencoder

Motors: http://www.allelectronics.com/cgi-bi...ar_Motors.html

IR Relay kit: http://www.alltronics.com/cgi-bin/it...%2DBoard%2DKit
For a non-encoder based control system... I think.
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post #97 of 837 Old 01-18-2008, 07:47 AM
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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 . 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.
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post #98 of 837 Old 01-18-2008, 09:35 AM
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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
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post #99 of 837 Old 01-18-2008, 11:02 AM
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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

Itai

Did I mention we are flat to 11?
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post #100 of 837 Old 01-19-2008, 07:14 AM
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Quote:
Originally Posted by Andy238 View Post

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
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post #101 of 837 Old 01-20-2008, 07:29 AM
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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
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post #102 of 837 Old 01-20-2008, 08:37 AM
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Quote:
Originally Posted by Freddie View Post

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:

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post #103 of 837 Old 01-20-2008, 08:49 AM
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Quote:
Originally Posted by Gunnar View Post

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
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post #104 of 837 Old 01-20-2008, 09:57 AM
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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?
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post #105 of 837 Old 01-20-2008, 02:06 PM
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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:


with a somfy motor fitted to the vertical tubing, but replace the end pulleys with spring balancers 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
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post #106 of 837 Old 01-20-2008, 03:25 PM
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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?
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post #107 of 837 Old 01-20-2008, 04:21 PM
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Quote:
Originally Posted by Andy238 View Post

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
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post #108 of 837 Old 01-21-2008, 02:45 AM
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Quote:
Originally Posted by benwillcox View Post

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:


with a somfy motor fitted to the vertical tubing, but replace the end pulleys with spring balancers 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
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post #109 of 837 Old 01-21-2008, 03:36 AM
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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
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post #110 of 837 Old 01-21-2008, 08:29 AM
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Nice find on the Secret Motor Driver, John.

Quote:
Originally Posted by HDGTX View Post

... 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...FQspFQodwjRCFg

and check out the tutorial. That is exactly the setup what we need!... I think.
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post #111 of 837 Old 01-21-2008, 08:32 AM - Thread Starter
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Quote:
Originally Posted by Andy238 View Post

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?

Quote:
Originally Posted by benwillcox View Post

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?
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post #112 of 837 Old 01-21-2008, 08:37 AM
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Hi again. The tutorial is actually here: http://www.youtube.com/watch?v=X4stWDy-bPA "How to Control A DC Motor from Your Computer".
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post #113 of 837 Old 01-21-2008, 09:05 AM
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Quote:
Originally Posted by HDGTX View Post

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.

Quote:
Originally Posted by HDGTX View Post

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.


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Originally Posted by Andy238 View Post

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

Quote:
Originally Posted by ScottJ0007 View Post

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
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post #114 of 837 Old 01-21-2008, 12:52 PM
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Quote:
Originally Posted by benwillcox View Post


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.
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post #115 of 837 Old 01-21-2008, 12:56 PM
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Quote:
Originally Posted by Andy238 View Post

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
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post #116 of 837 Old 01-21-2008, 06:48 PM
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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?
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post #117 of 837 Old 01-21-2008, 07:30 PM
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Still looking for an answer for my question, quoted below. Thanks:

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Originally Posted by R Harkness View Post

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?

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post #118 of 837 Old 01-22-2008, 06:11 AM
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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
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post #119 of 837 Old 01-22-2008, 06:57 AM
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post #120 of 837 Old 01-22-2008, 01:14 PM
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Ben, Is this what you mean by spring loade roller ? Here is a product from "Rollease" for roller shades....

http://rollease.com/SpringAssist.htm
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