DIY Curved AT screen with Somfy based automated masking - Page 4 - AVS Forum
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post #91 of 111 Old 08-28-2012, 01:16 PM
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Thanks!
Yes, I`m welding it up myself. Triangular supports in the corners is a good idea.
Found a local workshop that can roll the tubes to the desired radius. Used the Aussie Bob spreadsheet, and calculated the radius to about 11m. But according to the spreadsheet the pincushion distortion would be small enough that I`ve been thinking if it is better to use a flat screen? Not as cool, but give more flexibility.
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post #92 of 111 Old 08-30-2012, 07:34 PM - Thread Starter
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Gunnar,

The curved screen is definitely cool but if you can live with the pincushion a flat screen would be half as complex to build. The pincushion will be most noticeable on non-video images with vertical lines near the edge of the screen.

Make sure your screen border is wide enough to absorb the excess image because you will have to zoom in a little more than you would with a curved screen.

Don't forget to show your results -- I'm interested.

Cheers.

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post #93 of 111 Old 09-01-2012, 01:01 PM
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Thanks! I have mounted the PJ and a flat screen temporarily at a about 2.0 throw. I`ll try with/without the lens to see how visible the pincushion is. I`ve been designing a masking controller that I plan to use with this screen. If I go with a flat screen It will have a 4-motor masking system w/tubular motors. It can also be used with two motors. But if I feel that it is not necessary to change zoom when going from eg. 16:9 to 1,85:1 it would be nicer with a true CIH-setup. I have both a Lumagen Radiance and a RS45 projector w/lens memory, so I can try out the different options. I also would like to DIY a lens slide that is controlled by the masking system. I think that the guts from a scanner can be used as a horizontal moving slide. The one I took apart yesterday had a bipolar stepper motor that is easy to interface with a micro controller. But I may have to make a lens lift instead, because the lens have to move far sideways to get clear of the PJ air exhaust.
Your building thread is a great inspiration! Though my skill/budget/ambition is on a different planet, there are still ideas that I can use in my own room.
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post #94 of 111 Old 09-04-2012, 01:05 PM - Thread Starter
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Quote:
Originally Posted by Gunnar View Post

Thanks! I have mounted the PJ and a flat screen temporarily at a about 2.0 throw. I`ll try with/without the lens to see how visible the pincushion is. I`ve been designing a masking controller that I plan to use with this screen. If I go with a flat screen It will have a 4-motor masking system w/tubular motors. It can also be used with two motors. But if I feel that it is not necessary to change zoom when going from eg. 16:9 to 1,85:1 it would be nicer with a true CIH-setup. I have both a Lumagen Radiance and a RS45 projector w/lens memory, so I can try out the different options. I also would like to DIY a lens slide that is controlled by the masking system. I think that the guts from a scanner can be used as a horizontal moving slide. The one I took apart yesterday had a bipolar stepper motor that is easy to interface with a micro controller. But I may have to make a lens lift instead, because the lens have to move far sideways to get clear of the PJ air exhaust.
Your building thread is a great inspiration! Though my skill/budget/ambition is on a different planet, there are still ideas that I can use in my own room.

Love the idea of using the insides of a scanner for lens slide/lift. I'd guess you would need a pretty heavy duty scanner to get enough power for a lift though. Are you keeping a build thread? Would love to follow along..

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post #95 of 111 Old 09-04-2012, 02:54 PM
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Hooked up the steppermotor to a mikrocontroller today, and the accuracy seems very good. Will try a stronger motor and a more powerfull H-bridge to make it run a little faster.'
I have an old thread from when I was eksperimenting with the masking controller Here . I think I`ll start a new one for the new screen/lens lift-project.
Also tried the lens yesterday, and the pincushion is about 1cm at the middle of the sides. Not bad, but with the projector behind the back wall I can not have a screen much higher than 120cm, so it will be CIH, and curved.
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post #96 of 111 Old 09-07-2012, 05:19 AM
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Moggie, I noticed that you folded the edge of the screen material before attaching the grommets. Did you sew along the fold, or do something else to prevent frying?
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post #97 of 111 Old 09-09-2012, 09:46 AM - Thread Starter
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Hi Gunnar,

The screen material doesn't fray. The reason I folded it over was to create a stronger mount for the grommet. To hold the material together whilst fitting the grommets I used some strong double sided tape and ironed the crease.

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post #98 of 111 Old 09-10-2012, 12:52 PM
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Thanks!
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post #99 of 111 Old 09-17-2012, 09:59 AM
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Is it wrong to be turned on by the coolness of that HT setup?

Moggie, are those Klipsch THX Ultra2's? If so, how are you liking them?

- Terry
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post #100 of 111 Old 09-17-2012, 09:24 PM - Thread Starter
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Quote:
Originally Posted by terrys999 View Post

Is it wrong to be turned on by the coolness of that HT setup?
Moggie, are those Klipsch THX Ultra2's? If so, how are you liking them?
- Terry

I guess it depends on how literally eek.gif

The Klipsch setup is just awesome for movies. Incredible dynamic range, horn loaded design to help with multi-row seating arrangement and bullet proof. I find them quite musical as well although they are a little closer together than ideal. I added a pair of smaller Klipsch speakers as wides for a 9.2 setup and although blasphemy to some they really broaden the sound stage significantly. I've heard people complain about the harness of the Klipsch horns but in a acoustically treated room they sound sweet to me. No regrets.

Cheers.

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post #101 of 111 Old 09-18-2012, 05:44 AM
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Thanks for the update on the Klipsch speakers. I'm trying to decide between the B&W CT700 series and Klipsch's THX Ultra2 setup. Sadly I can't find a local audio shop to test either out.

My planned theater room is about 17' x 33', I'm very tempted to go 9.2 as well, but not sure. I'm just plain overwhelmed by the amount of choices for sound, visuals, acoustics, seating, etc. Thank goodness for AVSforum.com and its cool members.
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post #102 of 111 Old 10-20-2012, 01:04 AM
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Moggie,

Thanks for sharing the build this fantastic DIY screen! I'm also building my own screen, and I wondered what type of silicon O-rings you used to fasten sthe screen material with? And also where you got them from...

5261423681_1922ae4d09.jpg

Thanks again,
Arve Hunsbedt, Norway
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post #103 of 111 Old 10-22-2012, 07:16 PM - Thread Starter
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Hi Arve,

I know I have already replied via PM, but in case anyone else is interested here are the details:

I purchased the rubber o-rings from Amazon:

"-228 Buna O-Ring, 70A Durometer, Black, 2-1/4" ID, 2-1/2" OD, 1/8" Width (Pack of 10)"

They are available in all sorts of sizes. The quality is very good and I'd expect at least 10 years of service when used indoors. The great thing about the use of o-rings is that you can change the diameter to add or reduce tension to the screen. If you fit similar to the way I did you should be able to change them out if they ever became brittle or damaged. Note that I added little pieces of tubing to the self tapping screws so the screw thread did not cut into the o-ring.

BTW the brass grommets I used around the edge of the screen were also on the same Amazon order:
"Lord & Hodge 1073A-0 Grommet Kits"

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post #104 of 111 Old 10-27-2012, 12:46 PM
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I got my curved steel tubes for the screen frame Thursday, and I`m also interested in this. This seem to be a great way to attach the fabric. The DIY lens lift and the projector is in place, just waiting for the screen:)

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post #105 of 111 Old 06-12-2013, 01:04 PM - Thread Starter
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I've had a few questions about this build asked in my theater build thread. I thought the information would be helpful here also:

Question: is MDF ok for screen frame and can I explain the frame to steel chassis mounting better:

No problem with the screen frame being MDF. My horizontal pieces are exactly that. The vertical sections where made from some 2" finger jointed pine I had around the shop, but the horizontals are made from two strips of skirting board (baseboard for the Americans ;-) laminated together with wood glue AFTER being partially routed. The reason why I performed most of the routing prior to glue up was because the frame is curved. I glued the two strips using the frame as a curve profile to make the pre-bent piece. Routing the curve section would have been unwieldy. In retrospect I might have been able to make a straight frame and then bend as it was clamped into place, but I think the pre-bent approach made for a much cleaner and risk free fit.

I'll see if I can put together a sketch of the frame profile (horizontal sides) and the frame mounting a little bit later but I'll try and describe the build process:

1. the aluminium (British spelling just for you) flat was clamped onto the bend steel frame so that is was flush to the inside edge and overhung the outside edge by about 3/4" (this is important). Holes were drilled and regular intervals (6" I think) sized for future tapping.
2. The aluminum was removed and the holes in the steel were tapped. The aluminum was drilled oversize and countersunk so that it could be later fixed with countersunk head machine screws for a flush surface.
3. In a clean workshop the screen material was layed on the frame and the rubber O-rings were fitted (obviously I has screwed in self tapping screws with a nylon sleeve on the back side to match where I had fitted grommets around the edge of the screen) so that it was wrinkle free. The location of the tapped holes were marked in the screen material.
4. The screen cloth was removed and the marked holes were punched with a home made punch to about 5/8" or so. The reason for this will aid understanding of how it all then fits together...
5. After painting of the frame, the screen fabric was fitted for the final time. I let it sit overnight so it was correctly stretched and tensioned. Then the aluminum flats were re-attached to the steel frame with countersunk machine screws. These screws passed through the holes in the screen material and essentially clamped the screen material in place. I did think of adding small washers so the aluminum stood above the steel and would allow the screen material to retain tensioning from the O-rings. This probably would be an improvement, but my clamped approach has worked perfectly so I don't think it is necessary. I also believe the aluminum flat stiffened the steel so I did not get any additional sag once the screen was hoisted vertically.
6. Ok, so now the frame is placed on the aluminum and squared up and set so that the masking edge rods run free (equal separation across length of . It is attached through some holes drilled in the part of the aluminum flat that overhangs the steel ... you can screw through the overlap and into the wood frame. Presto!
7. Note that I did find that the 1/8" aluminum flat was not sufficient to prevent the masking from binding. Either shim out with washers as described in step 5 or do what I did which was to stick a strip of approx. 1/8" think plastic tape on top of the aluminum before the frame thus lifting it an additional 1/8". Edit: Or use 1/4" aluminum flats instead

Here is the hastily drawn visual:




Question: follow up on size of washers to separate aluminum strip and steel to allow screen material to move :

The spacing washer is just an idea. The washers would have to be small enough to sit in the punched holes in the screen fabric. The idea is that you would want the fabric to be able to move a little and not be trapped. Penny washers would be too big even if you enlarged the punched holes. BTW I'm not advocating this approach since I have not found it necessary after living with my screen for two years -- perhaps a good idea with a different, more stretchy, fabric though...

1/4" aluminum strips would be perfectly fine, just a little more expensive. The extra tape spacer was an afterthought because although the edge of the masking moved perfectly well initially, it became tight when wrapped in velvet.

Here are the pics of the profile as promised:


Couple of notes:
  • Frame dimensions are approximately 4 1/2" wide and 1 3/4" deep.
  • The inside routing profile is, from left to right: (i) cutout for bungee cord (aluminum strip just covers this to prevent cord from jumping out), (ii) track cutout (depth so track is flush with surface), (iii) little slot I used to staple the velvet so that the staples could not snag on the masking as it moved (possibly not required)
  • The center section, where the inside of the track ends had a pocket routed out so that the bungee cords could cross over.
  • The vertical parts of the frame obviously are different on the inside to (i) create a pocket for the roll of masking fabric and (ii) allow the insertion of a tube for smooth edge for the masking to rub against -- I think my thread has enough pictures of this but let me know if you have questions.

- Paul

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post #106 of 111 Old 06-13-2013, 12:18 PM
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Hi Moggie! I really like your excellent work,it never stops to amaze me. You are a gifted man, and a true inspiration! Thanks for choosing to share this project here at the forum. smile.gif
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post #107 of 111 Old 06-13-2013, 07:28 PM
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Moggie: Your willingness to share information about your fantastic screen build is very much appreciated. I am sure that you have given many forum members many great ideas on how to build a masking system.

Thanks
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post #108 of 111 Old 06-18-2013, 08:14 PM - Thread Starter
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Thanks guys. Always happy to share. Makes the hobby more fun!
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post #109 of 111 Old 09-10-2013, 02:42 PM
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Hi Moogie, just wanted to say thank you for sharing all your experience and details. Great work and amazing project.

Wanted: M&K Sound MPS-2525P, SS-250P, MPS-2510P, S-150P
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post #110 of 111 Old 11-07-2013, 05:57 PM
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Paul - congrats on being the AVS HT of the month for Nov-2013!!!!!
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post #111 of 111 Old 11-07-2013, 11:01 PM - Thread Starter
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Thanks Mike. Maybe you will be next? with your new "11.3 heaven" build smile.gif

- Paul.

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