4-Way Acoustically Transparent Masking - Page 12

I like your thinking. There is a lot of discussion about the benefits of CIH, but after having my setup for a while, I'm of the opinion that bigger is better, no matter what the aspect ratio. In my case, my room height was the limiting factor, but I could go about as wide as I wanted, so 2.35:1 made sense. In a room where the width is the limiting factor and you can go as tall as you want, then I agree that it makes since to go with a taller screen as you have done. That lets you get the biggest picture possible (if you choose), no matter what the native aspect ratio of the movie. I sit 10 feet from a screen that is a little over 10 feet wide in 2.35:1. I love it. When I watch a movie that is 16:9 or 4:3, I feel it is too small. In these situations it would be nice to have a bigger picture if I had a taller room.

In your case, a 4-way masking system is more important than ever and I think your plan of the Carada/Goelst system combo will work well. I like your mock up drawing. It looks very good. I agree with your plan that a bevel on the side masking that rides close to the screen is good idea. Overall I think you have a very good plan, and at a cost of $5,000, compared to $19,000, I would probably make the same decisions as you have made.

My humble attempt in this thread has been to try to show an option for people looking for ideas to do a DIY manual masking system in the $500 range. In my recent attempts to motorize my system, I have been hoping to keep the motorization below a couple hundred dollars. My system is pretty labor intense and I realize this is not an option for everyone.

In all honesty, I have not intensely looked into the commercial systems that are in the price range you are looking at. My off-the-cuff thought when I first read your post was that if I was spending $5,000 + on a system, I would not want to mix components from different manufacturers. However, if a complete solution is in the $19,000 range, then I completely understand your choice and think it is a very viable plan. Your drawing looks great.

Uh oh... Now I'm thinking about those 19" panels on each side of your screen.... If you ditched those, you could still have your 61" in height, but get a 2.40:1 screen that was 146" wide instead of only 124" wide.... ===> now you're talking big...

(Just playing with you... I like your plan, -- but I would take another look at the SMX option before making a final decision )

- Scott

Ivan,
I think the gear must be glued on. Getting it off was tough. The best way would be to find a tiny gear puller, but I couldn't find anything that small. I ended up using an allen wrench as a pry bar. Using the largest allen wrench possible, I fit the short end of the allen wrench underneath the gear and then pried it up. The danger of doing it this way is that you could damage the motor. Fortunately my motor was fine after I got the gear off. - Scott

I finally got the rotator motor mounted to the shaft of my gear motor. I took the shaft of the gear motor to a local machine shop and had them bore a 1/8" hole in the end of the shaft. I bought a 1/8" shaft and some hub mounts from ServoCity.com and then pieced it all together. Here are some pics. Later today I will try hooking it all up to my masking system to see if it works...

This is the armature removed from my gear motor


This is the end of the shaft before being drilled


After being drilled


Here, I have inserted the 1/8" shafted into the end of the gear motor shaft


The new 1/8" shaft now protrudes out of the end of the motor housing


I used hub mounts to connect the small motor to the new 1/8" shaft


The infamous "hall sensor"...


Full view of the new setup

Great news! I got the new motor hooked up. It works! The repeatability is very good. I won't say it is perfect, but it is certainly very acceptable.

I still have a couple of small issues that I will work on. First, I did not get the two motors exactly on center with each other and there is a little bit of vibration that is audible. Its not terrible, but it is noticeable to me. Secondly, I think I am going to use a smaller pulley on the cables so that my masking moves a little slower. This will also give me more precision in fine tuning the exact point that I want the masking to stop.

Overall, I am VERY encouraged!

- Scott

Yes, that coupling looks like it would help a lot. The other thing I am considering is to remove the hall sensor board from the rotator motor and removing the "donut" magnet from the shaft of the rotator motor and attaching them directly to the 1/8" shaft that I added to the gear motor. The rotator motor really isn't needed at all. I just need to figure out a way to mount the hall sensor board to the back of the gear motor and have it lined up with the donut magnet.

Thanks John.

I think I might attempt to re-mount the encoder board directly to the new 1/8" shaft and leave the rotator motor out altogether. This will solve the problem with the vibration.

I don't have any new pictures of the motor mount, but it is the exact same as what I showed in the original video. Once I get the last few bugs worked out, I will post a complete set of new pictures and I might do another video as well. - Scott

TeeCue, Thanks for the magnet link. I order a couple this evening. I've started work on mounting the hall effect sensor directly to the new gear motor. Yesterday I disassemble to old motor and got the hall sensor encoder board and the ring magnet off the old shaft. I had considered taking my 1/8" shaft back to the machine shop to reduce the end of it to 2.5mm to fit the ring magnet, but I decided to order a new magnet from the link you gave instead. Thanks! - Scott

No flash. It is just the room light overhead. Color balance set to "auto". I'm using a little Canon Digital Elph SD600. It takes great close-up pictures, especially in "digital macro" mode. I have a more expensive full sized Canon, but it doesn't match the close-up quality of the little Elph.

(Not off topic at all! I think good pictures help make a good thread. )

MOTORIZATION SUCCESS!!!!!

It worked! I mounted the hall sensor encoder directly to the motor. It works perfectly!

First, I had to remove the hall sensor board from the small rotator motor. I wanted to keep the plastic mounting piece that was part of the old motor. I had a hard time figuring out how to dismantle the old motor so I did it the ugly way... I took a hack saw to it. Here is a picture of the armature and hall sensor board of the rotator motor after I removed the motor housing.


I used the hack saw again to cut the armature off (I know, there is probably a better way, but...). Here is the encoder board and the original ring magnet.


Here is the underside of the plastic mounting piece. This picture does not show it, but I clipped off the two small motor brushes and also bent back the motor connections so they wouldn't be in the way when mounted onto the new motor. I also drilled out the shaft hole to fit the 1/8" shaft extension that I put on the new motor.


I bought a new diametrically magnetized ring magnet (the silver one in the picture) from www.kjmagnetics.com (thanks TeeCue for the link!!!). The new magnet has a 1/8" bore, which is a perfect fit for the new motor shaft extension. This is a neodymium magnet which is an amazingly strong magnet. It is a little smaller in diameter than the original magnet, but WAY more powerful. Both magnets have a single north and south pole. The new magnet works perfectly.


Here is the hall sensor board and new ring magnet mounted to the new motor. I used super glue to mount the board to the motor housing.




Finally, here is a VIDEO OF THE NEW SYSTEM IN USE.



TeeCue, ifeliciano, HDGTX, thank you guys so much for your help! I could not have done it without you.

I am also going to motorize my horizontal masking and program everything into my Harmony One universal remote so that everything, including the projector aspect ratio and the Prismasonic anamorphic lens, is all automated with the push of a single button. I'll post more details and more pictures when I get everything finished. For now, I just wanted to get something up quick to let you know that IT WORKED!

Thanks again. You guys are great!

- Scott

Axel,

Thank you. My original goal was to be able to simply buy the rotator for about $80, make a few minor modifications, and have an extremely easy DIY solution that anyone could implement. The cost has turned out to be closer to $200 and it is a little more involved than a plug-n-play solution, but it really is not that difficult. I realize that this thread may have made it seem complicated because there were many set-backs and alternatives that we explored. However, if you are handy and can solder, it is not a difficult project.

I will build at least three more of these. One will be for my horizontal masking, and I will use many of the same concepts when I build a lift for my projector. I am also going to build a projector lift for a friend of mine.

I expect I will do some more fine-tuning while I build the rest of the motor controllers for my projects. At that point I plan on putting together a parts list with step-by-step instructions. (Maybe even a step-by-step video).

I'm hoping that this can be motorization solution that many of the DIY'ers on this forum can implement. It is not as slick as some of the commercial systems, but with 99 easily programmable set points, learnable IR control, nonvolatile memory, and extremely accurate repeatability, it is very functional.

- Scott