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Discussion Starter #1
As others have decided, I too do not want to sacrifice 16:9 & 4:3 screen size by going with a single-mask 2.35:1 CIH screen configuration - Therefore I am planning to pursue a two-way masking approach. I do not want to spend the premium price for an off-the-shelf two-way masking system; therefore I am considering a more moderate approach. After perusing multiple threads on do-it-yourself masking systems, I am contemplating a hybrid approach which hopefully compromises a balance between sensible cost, performance, and time.


A quick bit of background... I have a ~13' x 20' theater with approximately a 144 16:9 screen driven most likely with a Panasonic PT-AE7000 3D projector. I am hoping to have the ability to configure presets for the most common screen aspect configurations (2.35:1, 16:9, 4:3). I have not concluded whether I will purchase a fixed screen or paint a screen on existing wall.


For sake of time and simplicity, I am thinking of using rollers with a single Somfy motor for horizontal masking and was thinking about simply using a powered curtain rod for vertical masking.


Depending on screen selection, I am either thinking of having the velvet mask roll off of the back of the roller with curtain rod tucked underneath (mounted to angle iron beyond the ends of the roller mask) OR having the mask roll off the front of the roller with the curtain rod attached to the ceiling in front of the roller.


To maintain proper alignment / tension of the roller masks, I am thinking of having the upper and lower rollers linked via criss-cross cables with floating pulleys. All cables would attach to mask bars with adjustable turn-buckles with springs to allow for variation in diameter as the fabric rolls up on the rollers. With the upper and lower rollers linked in this configuration, I believe I can get by with a single Somfy (LT30, ST30, or ST50) motor with bearings for all other roller ends.


As the cables wrap and unwrap from the rollers, there will be some slight side movement of the cables, therefore I figured I would configure the criss-cross pulleys allowing them to float on shimmed bolts mounted between two pieces of angle iron.


Attached are a few rough sketches which hopefully will help illustrate what I am describing.


I am trying to finish off my rough-in wiring (including any screen mask control wiring) and add any necessary framing bracing behind the drywall so any comments, suggestions, or feedback is greatly appreciated.


Regards,

JAR


 

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Discussion Starter #2
I am leaning towards the configuration with the projection screen on a frame where the vertical mask material would roll off the front of the roller and the horizontal mask would utilize a motorized curtain rod mounted to the ceiling slightly in front of the vertical mask rollers. I am thinking this approach may work well.


For vertical masking, the Somfy has three presets (Up, Down, & User) - this will correlate nicely with the three stops for the main aspect ratios I am interested.


Also, for horizontal masking the standard garden variety (eBay) motorized curtain rods essentially have two presets (Open & Closed) - these stops can be set for the two horizontal positions I need:

AspectH1H2V1V2V3
4:3xx
2.35:1xx
1.85:1xx
16:9xx

With this configuration, I will not need any position sensors (reed switch) or state machine to guide which direction the curtains and rollers need to move from a given current aspect position (state) to another. All that is needed is very simple logic to translate the desired aspect command into 1 of 2 horizontal and 1 of 3 vertical switch closures per the table above. This can easily be accomplished with diodes, relays, or perhaps using IR macros.


If 1.66:1 (or other) aspect ratio is needed, I could always drop in reed switch(es) with logic, find a curtain rod with more programmable presets, or just program IR macros to make an intermediate timed stop with delay commands.


Attached are drawings which show the horizontal masking approach (green) and the vertical masking approach (blue). Also attached is theater layout.


As always any insight, experiences, and/or feedback are appreciated.


Regards,

JAR


 

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Discussion Starter #4
In my particular case, I am still in the rough-in stage, so I am putting in blocking into the wall into which I can run lag screws/bolts. For vertical masking - The top roller brackets will mount right on top of the drywall with screws going into wall header. The lower roller and floating pulleys will also mount onto drywall with screws into the added blocking. See attached picture for blocking shown in orange. If drywall indentation is a problem, I may place scrap 12 gauge aluminum sheet squares under the brackets on top of the drywall.


If the wall was already finished, I would probably mount items on a flat 1x4 mounted securely to the wall - possibly using t-nuts from behind...


For horizontal masking, the curtain rod will attach to the ceiling. I will be using resilient channel under the drywall, so I will first attach a 1x4 flat on the ceiling drywall with screws into the resilient channel. The curtain rod will then simply attach to the 1x4.


I hadn't stumbled onto the links you had provided before - interesting approaches. My counter-balanced cable pull with floating pulleys approach will hopefully eliminate the need to have tracks for the flat aluminum edges to travel in and should also minimize torque requirements in either direction. My approach should also maintain symmetric/synchronized operation of both upper and lower rollers, where single-ended cable approaches may suffer from non-symmetric operation due to diameter differences between cable wrapped on bare roller versus accumulative fabric diameter. I have seen where others have compensated for this non-symmetry by wrapping progressive layers of tape under the cable wrap...

http://www.avsforum.com/avs-vb/showt...3#post12251833


To enable adjustment of the mask (flat aluminum edges) from the screen front, I plan to slot the floating pulley mounting holes as shown in the second attachment.

 

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Now that Ive had time to digest:


For the vertical masking- why do you need the weights at the top?

Regarding the pulleys- why do you say cris-cross?

I interpreted your photos as if there are 4 pulleys each side, 2 per cable but they are not crossed (X)
 

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Discussion Starter #7
The weights at the top (& bottom) of the side masks are to keep tension on the masking material so that it lays flat instead of bunching up like a normal curtain would lay.


The "criss-cross" refers to the cable on the pulleys - it may be a little difficult to see, but in my original hand-drawn sketches, I try to show how the one cable comes from the back side of the top roller, "criss-crosses" on the pulleys, and then attaches to the front fabric of the bottom roller. Likewise, another cable comes from the back side of the bottom roller, "criss-crosses" on the pulleys, and then attaches to the front fabric of the top roller. This balanced configuration is what enables balanced operation of both rollers with only one tubular drive motor. As mentioned previously, the pulleys also maintain the pull of the fabric mask in a plane just above the screen, which should negate the need for guides.


Let me know if this is still unclear and I will try to clean up the drawing.


Your latest link demonstrates incredible craftsmanship - I wish I had more time...
 

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Quote:
Originally Posted by JARathje /forum/post/20983517


The weights at the top (& bottom) of the side masks are to keep tension on the masking material so that it lays flat instead of bunching up like a normal curtain would lay.


The "criss-cross" refers to the cable on the pulleys - it may be a little difficult to see, but in my original hand-drawn sketches, I try to show how the one cable comes from the back side of the top roller, "criss-crosses" on the pulleys, and then attaches to the front fabric of the bottom roller. Likewise, another cable comes from the back side of the bottom roller, "criss-crosses" on the pulleys, and then attaches to the front fabric of the top roller. This balanced configuration is what enables balanced operation of both rollers with only one tubular drive motor. As mentioned previously, the pulleys also maintain the pull of the fabric mask in a plane just above the screen, which should negate the need for guides.


Let me know if this is still unclear and I will try to clean up the drawing.


Your latest link demonstrates incredible craftsmanship - I wish I had more time...

Its clear now. A channel wouldnt be too bad though. You'd only need a few feet of it.

For the vertical mask...the ones that bunch up dont look too bad. remember all the light gets soaked up so i'm no sure if you'll even see it.

This thread is going into my bookmarks to reference when I do get around to mine.
 

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Will be watching your thread and look forward to your progress.

I have found a powered curtain track I would like to use when & if I get to build my living room theater; Power Curtain (see link below).
www.powercurtain.com

It has the usual open, close & stops buttons on the wall mount ctl pnl (even provision for two trk control, an A & B). I was wondering if one could wire in several switches (hall effect, reed or snap action swts) to trigger the same signal as the "Stop" button does when pushed & thus trigger as many possible stops as you have swts for different aspect ratios postions. The switches could be placed along a rail system to give them adjustablly. Not sure at present how to make this happen... but still thinking this thru. Maybe a bus bar connecting all swts & then connect that to the same "Stop" button within the wall mounted panel???? Of course the motor would stop at every swt, unless one could come up with a way to turn on only the swt at the desired AR position & leave the others unpowered & untriggerable (is that a word?).


John
 

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Discussion Starter #10
I have looked at the Power Curtain as well. I might upgrade to the Somfy Glydea 60e DCT curtain system to have an additional "MY" program spot added to the "OPEN" & "CLOSE" presets - this would also allow IR compatibility with the Somfy roller motor.


When I was contemplating using reed/microswitches for preset stops, I was thinking of creating a state machine (with a microcontroller, PIC, or Programmable Array Logic) to determine which direction to run the horizontal & vertical motors until the next desired state was achieved. The time versus money factor now instead has me leaning towards the Somfy solution.


Just finished wiring, HVAC, and rough in inspections. Have blocked up front theater wall to hold rollers and pulleys per my drawings. Hope to get the theater sprayed with Icynene next week. Looking into decoupling theater ceiling on springs - a little tricky as ceiling joists are on a 45 degree angle to theater sides. May be a bit before drywall - Also finishing off rest of basement, so progress may be a bit slower that I would like...
 

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Discussion Starter #11
Have made a bit of progress since the last posting...
QuietClips, resilient channel, double 5/8 drywall with Green Glue installed.
Had 1 square tube projection 11'W x 6'H screen frame made at local machine shop.
Drilled holes through floating double drywall to studs/blocking.
Procured Somfy Sonesse ST30 DCT roller shade motor, 2 tubes, & accessories,
Procured pulleys & Eagle Aspen ROTR100 Antenna Rotator.
Mounted screen frame, rollers, & pulleys on 2 stand-offs to studs/block to maintain isolation from floating drywall.
Made an 11 wood pulley for ROTR100 to control traverse curtain rod for horizontal masking.
Installed angle aluminum to hold traverse rod, mounted ROTR100, and cables/pulleys to control horizontal masking. Confirmed / testing operation.
Built 14.5H x 13'W x 6.5'D bass trap riser.


I decided to use the ROTR100 instead of motorized traverse rod for several reasons: Up to 99 presets instead of 2 or 3; ~0.1 increment adjustments; & cost... I opted for the large pulley approach for the ROTR100 versus tearing it apart as I am not a big fan of disassembling new items unless I am greatly enhancing the performance, appearance, or reliability.


I also shifted my aspect thoughts a bit as well - rather than having a native 16:9 frame, I decided to use a native 1.85:1 frame. I will couple this with the AE7000 power zoom preset capability. Essentially 1.85:1, 16:9, & 4:3 will share CIH and 1.85 & 2.35:1 will share CIW. This also shifts a requirement for a Vertical preset to instead a Horizontal preset, where I have plenty to spare. New presets are as follows:

AspectH1H2H3V1V2
1.85:1xx
16:9xx
4:3xx
2.35:1xx


Pictures follow...
 

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Using the large pulley approach on the ROTR100, How long does it take for your masks to move into position? Does it seem to have plenty of power to move the masks or does it struggle? Yours is the first project I have seen that used the ROTR100 fully intact. If this works well, its probably the easiest diy automated mask to implement.

I am thinking of using Panel Track curtains from IKEA and automating them using the ROTR100 simply move the cord on the curtains. if this works, my solution will only cost about 150 total for side masking.
 

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Discussion Starter #14
The ROTR100 turns at 1 RPM and my pulley is 10-3/8" in diameter so travel is 32.6 inches per minute (1RPM x 10.375inches x 3.1415).


In my particular case the minimum (4:3) to maximum (2.35:1) masking position travel is less than 18 inches which takes less than ~33 seconds.


The ST30 has programmable rotation speed so if I wanted I could match horizontal and vertical masking speeds fairly close.


The ROTR100 in this configuration seems to have more than enough torque for the traverse rod.
 

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Quote:
Originally Posted by lamborghi /forum/post/21355336


Hi John,


Just a tip, I have had a very good experience with powercurtain dot com outfit. They shipped my order within two working days. I was able to order online using my PayPal account. Arrived with a complete set of instructions on how to install. Just an overall good experience.

Just wondering of you're going to SPAM your way through other sections of the forum because if you are, I'm going to report all of your post, including this one of my own.
 

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Quote:
Originally Posted by calimark /forum/post/21357002


Were you able to find 2" tubes over 12'? If so where from?


I got some via a Drapery / Blind Wholesale Supply. Had to locate them in a Catalog though, as they are not all that common. never did find 12'ers though...had to join two together...6'ers...with a large 3' Dowel as a interior Bridge, secured with Gorilla Glue.
 

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I was under the impession the tubes needed a notch or some cutout at the end to fit the somfy ?


If thats not the case, then I'd probably be able to find some locally.

JARathe, what thickness did you go with?


MM, I'd prefer a single piece even if I have to shell out a few more $
 

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Discussion Starter #20

Quote:
Originally Posted by calimark /forum/post/21363135


JARathe, what thickness did you go with?

Calimark, I went with 2.00" O.D. with .065" wall thickness. This worked perfectly with Rollease RA2 - 1.5" to 2" Tube Adapters, which allowed use of Rollease REP53 End Plugs, & ST30 motor.
 
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