AVS Forum banner

DIY Curved AT screen with Somfy based automated masking

86K views 127 replies 35 participants last post by  Curamrda 
#1 ·
Teaser:



========= Original Post ==============


I posted this in my build thread, but then thought that it might be better to document here....


It is with great trepidation and mixed feelings that I'm launching into my screen building. The reason for the emotions is that I am so desperate to watch some movies in my HT since I've hardly seen any since I started my build and the movie-catch up is going to take weeks.


Anyway, I haven't come this far to give up on my screen plan, so here is the first installment.


The plan:

130 wide curved AT screen with integrated (within the frame border) horizontal masking with full independent left/right masking control. The goals I've set are that I want to create a professional job that is less than 4 thick so that it disappears into the screen wall frame, the mechanism needs to be simple to reduce build and setup time and the budget should be around $1600. Possible.??? We shall see.


After numerous design scribbles I realized that building a curved screen complicated what really should be a fairly simple process for a flat screen. Some of the problems include attachment to the screen fabric along the arc whilst allowing a very close fitting mask, bending of any linear slide mechanism for the mask, keeping a simple drive mechanism that can stay within the 4 thickness goal.


The basic construction approach is shown here:




The goal is to leverage the precise repeatability of the new Somfy ILT motors and to use a constant spring to provide closing tension. I.e. no pulleys, no wires, just the KISS approach. Of course the devil is in the details and I'm under no illusions that a cheap, curved and smooth linear motion track that doesn't get stuck is the key. The plan is to have the mask ride right next to the screen fabric (to prevent shadows) and to have a minimal gap at top and bottom for the leading edge of the mask.


Step 1. I wanted to be sure that the size was going to work, particularly the location of the leading edge of the mask at the prime aspect ratios. The leading edge of the mask will be solid and I didn't want this to fall in the direct path of the tweeters.




Step 2 was to get the horizontal frame members bent to my calculated 42' radius. My preference was to use an extruded aluminum frame with various t-slot cutouts for convenient attachment but I completely failed to find somebody to bend these or to purchase them pre-bent. The problem with bending aluminum is that it is difficult to keep the extrusion profile intact without the correct bending die or by bending as the extrusion is made.


My fallback was to opt for a steel frame. Aluminum would have been nice and lighter but one advantage of steel is that it is much easier to bend and weld. So off to my local steel yard to purchase the steel and to get them to run a couple of pieces through their Eagle rolling machine. Cha-ching: $320 including bending.


Once home I cut the pieces to size and welded up the frame, taking care to ensure it stayed square. The primitive rolling machine the metal yard used did get the radius curve correct but gave me a slight warp which I needed to work out during the welding process. You can see a laser level in the second photo keeping me honest.




Once welded it was outside to do a bit of cleanup of the welds on the inside edge (the side that I plan on using a cunning plan to mount the screen fabric). In fact the screen attachment plan is so secretive that I don't know it myself yet





Then a coat of primer. You can see the cleaned up weld to create a perfectly smooth surface.




It was precisely at this point that I panicked and questioned what the heck I was doing and call up Jason Turk at AVS to see if I could get a 130 non-masking SMX screen cheap. No luck. A few beers later I calmed down and got my wife to lift this monster back into the garage. Then I panicked again what if this wouldn't fit through the theater doorway? Luckily, I think it will simply due to my fortunate door arrangement (alignment).




I then spent the rest of the day on-line ordering parts:

2x Somfy Sonesse LT50 ILT motors: $740 (yikes!)

RS485 interface: $60

2 tubes and roller blind mounting h/w: $100

Grommets + tools, rubber rings: $32

USB to RS485 interface: $40

6061 aluminum bar, t-tracks, etc: $70

SeymorAV CenterStage XD fabric: $280

Total: $1,322


Plus steel, total to date: $1,622. Well, that's blown the budget already so I might as well give up... Seriously, other than some miscellaneous fabric, misc hardware, some scraps of steel plate and some MDF (most of which I have lying around) I think I have all the raw materials I need.


I should probably explain my choice of the expensive Somfy motors a little. There is no way to get around the fact that these are expensive, but I know from experience how much time a motor control system takes to build when I converted my home mill/lathe tp CNC. The neatness of the Somfy system, the quietness of their Sonesse motor (44 dbA), the ability to program 16 intermediate stopping positions, encoder based positioning and the fact that the RS485 control bus can easily interface to IR/RF/Z-wave, etc makes this an obvious cost/time tradeoff to me. If anybody is curious I'd suggest you read up on the ILT line of motors and their SDN control bus. I briefly looked at the SMX masking system functionality and this motor and controllers can do everything that can do


To be continued
 
See less See more
10
#77 ·
Just my $0.02 worth. I did curve a flat screen a few years ago, but to so required me to reverse the frame because as I flexed the flat alloy the right way around, the frame bowed. Basically it took on the same shape as the pincushion I was wanting to correct. As a result, it also slumped leaving the fabric loose. Because I had build a baffle wall, I was not able to retention the fabric. Reversing the frame was the only solution that worked with what I had done. It was my first attempt and I didn't really have the resources at the time to make variations to the design and I ended up making a MDF frame to cover the alloy frame.


In hind sight if I was to do this again, I would make the baffle wall taller and attach the flat frame to the baffle wall on small spacers (so I could get my hands in behind the screen later on) before attaching the fabric. Because of the tension required to flex the screen, i still think that my method of drilling right through the frame and baffle wall is still required. So I would set the "height" of the screen flat. In my case, my baffle wall was concave (made of three equal sized panels) and this pre-mounting would have to be done on the centre portion first.
 
#78 ·

Quote:
Originally Posted by Moggie /forum/post/19935679


For example, one way would be to purchase some rectangular aluminum extrusion with two t-slots on the front face and one on the edges. You could then stretch the screen material and fasten to the inner most t-track on the front face (with t-track covers as others have done). The outermost t-track could be used for a masking system just like mine. The wooden screen border would then be fastened with right angle brackets to the t-track on the sides of the frame.


Another way would be to grommet the screen cloth and attach with rubber o-rings around the inside of a frame made from square aluminum extrusion and use simple 'u' aluminum extrusion facing up at bottom and down at top in front of the screen. It would be easier to make glides for 'u' molding than t-track. Attaching the border without much of a gap would be harder in this case...


Check out the other builds and combine ideas from each. Don't forget to document your work

I'm blind
. Just saw this post. Good thing that I came up with a mix of these two ideas: grommet the screen cloth and attach with ruber o-ringt to the inner most t-slot of a rectangular aluminum extrusion with two t-slots.


And maybe I will go with 3 way masking... CIA...


Thx...


[]s Humberto
 
#79 ·
Several folks have asked me for the list of Somfy parts I ended up using. Here is the list with updated part numbers (because Somfy has made it even more confusing!):


[x2] Somfy Sonesse (ST) ILT2 504S2 Motor (110V AC) Round Head Motor #1030077 (#1030053 for star head version)

Note: you don't need the limit setting tool if you use the 4ILT interface.

Note: make sure you get the ILT2 version of the motor (see 4ILT data sheet)

Note: I used the round rather than star head because of the lower profile end allowed it to mount closer to the screen frame

Note: this can be programmed for 8 different stop positions per motor. Two of these positions can be triggered by contact closure; all can be retrieved via IR or RS485.


[x1] Somfy RS485 4ILT interface #1870130. Check out this page for more information.

[x1] Somfy IR Sensor #9154205

[x1] Somfy IR transmitter- IRT803 #1870132


Hardware for motor attachment

[x2] 2" roller blind tube #1781148 (or equivalent)

[x2] Somfy LT50 Idler End10 MM #9420800

[x2] Somfy LT50 Idler End Bracket 10mm #9410635

[x2] Somfy LT50 2" Soft Clip Drive #9206089


Tools:

Pop rivet gun to attach soft clip drive to tube


Optional:

RS232 to RS485 convertor to control 4ILT interface from a computer or A/V equipment (assuming you don't want to use IR)


Hope this helps.
 
#123 ·
Several folks have asked me for the list of Somfy parts I ended up using. Here is the list with updated part numbers (because Somfy has made it even more confusing!):

[x2] Somfy Sonesse (ST) ILT2 504S2 Motor (110V AC) Round Head Motor #1030077 (#1030053 for star head version)
Note: you don't need the limit setting tool if you use the 4ILT interface.
Note: make sure you get the ILT2 version of the motor (see 4ILT data sheet)
Note: I used the round rather than star head because of the lower profile end allowed it to mount closer to the screen frame
Note: this can be programmed for 8 different stop positions per motor. Two of these positions can be triggered by contact closure; all can be retrieved via IR or RS485.

[x1] Somfy RS485 4ILT interface #1870130. Check out this page for more information.
[x1] Somfy IR Sensor #9154205
[x1] Somfy IR transmitter- IRT803 #1870132

Hardware for motor attachment
[x2] 2" roller blind tube #1781148 (or equivalent)
[x2] Somfy LT50 Idler End10 MM #9420800
[x2] Somfy LT50 Idler End Bracket 10mm #9410635
[x2] Somfy LT50 2" Soft Clip Drive #9206089

Tools:
Pop rivet gun to attach soft clip drive to tube

Optional:
RS232 to RS485 convertor to control 4ILT interface from a computer or A/V equipment (assuming you don't want to use IR)

Hope this helps.
Hey Moggie

Just got my ILT motors (506 RH) and my 4ILT; however, it seems I need to inject 12v into the line somewhere, Seems this can be done with the single motor tap or just putting two x 12v lines into RJ45 that carries RS485 in 4ILT.

I hooked up via RS485 DIRECTLY to motor, so just 110v and RS485 and Gnd (pins 1 and 3 IIRC) from USB to RS485. I can read serial no, etc, but cannot write anything (always get errors) or male motor move

Did you connect a DC supply anywhere on yours?

TIA

Mark
 
#81 ·

Quote:
Originally Posted by mandarax /forum/post/21830219


What an amazing thread and an amazing room ... great read and a beautiful result.

Thanks! Just got done watching "The Girl with a Dragon Tattoo". I just love being able to open up the whole screen..
 
#85 ·

Quote:
Originally Posted by GetGray  /t/1295320/diy-curved-at-screen-with-somfy-based-automated-masking/60#post_22113503


Not nerdy enough I guess. I had to look it up:: bat'leths

Bat'leth is now my new word for the week (I feel newly educated
)


They are unusual columns but designed to maximize the walkways. Here is how they turned out when finished:

 
#87 ·

Quote:
Originally Posted by phisch  /t/1295320/diy-curved-at-screen-with-somfy-based-automated-masking/0_100#post_22301220


Moggie

I'm not sure if I missed this earlier in the thread or not, but how did you determince the 42' curve radius for your screen to use with your projector/lens setup? Is there a calculator or spreadsheet available to determine the radius?
Email me your specifics (throw distance, screen height) and I'll calculate it for you.


Scott

aut

techht

dut

com
 
#89 ·
Moggie, what size tubes did you use for the frame? I`m planning doing a 110" wide curved steel frame, and thought of using 25mm square cross section tubes, 2mm wall thickness. I also in doubt if really needing the two supports? Do you think the frame would sag without them? BTW, amazing room and screen you have!
 
#90 ·
Thanks Gunnar.


I believe the steel tubes were 1.5" square with 3/32" walls, so very close to what you are thinking. The cross support are smaller 1" square thin wall. Depending on how you mount the frame you may or may not need the cross supports. Even my heavy duty frame had a little flex to it. The other thing to think about is keeping the frame square. The cross supports help achieve this although another option would be to weld some triangular supports in the corners. At 110" wide (mine was 130") I'd be tempted to skip the cross supports and beef up the corners. Are you welding this up yourself? You can always add the cross supports as an afterthought.


Good luck.
 
#91 ·
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.
 
#92 ·
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.
 
#93 ·
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.
 
#94 ·

Quote:
Originally Posted by Gunnar  /t/1295320/diy-curved-at-screen-with-somfy-based-automated-masking/90#post_22363229


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..
 
#95 ·
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.
 
#97 ·
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.
 
#100 ·

Quote:
Originally Posted by terrys999  /t/1295320/diy-curved-at-screen-with-somfy-based-automated-masking/90#post_22409284


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



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.
 
#101 ·
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.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top