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Topic: DIY Automated Horizontal Masking Screen
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Joined: Nov 19, 2008
Posts: 4
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Hi All,

This was my HT setup in 2005. Many things have changed since then, but I would first like you all to familiarize yourself with this setup before I post my new fully renovated home theatre. I would like to show everyone the benefits of horizontal masking and how something so simple can improve the contrast in a movie.

I will post my new renovated home theatre soon!! In the next couple of days...

My Home Theatre as of 2005 comprises of the following:

Infocus Screenplay 5000 AU$2950
Phillips Dolby digital amplifier AU$450
2x pairs of Tannoy R1 speakers + matched Centre speaker AU$1200
12" Isobaric Subwoofer Kit AU$450
Playmaster Amplifier 200w +200w Kit to drive Subwoofer AU$599
100" Home Built Screen with Motorised Horitontal Curtains AU$400
HTPC AU$800
Fusion HDTV card AU$99

Total: AU$7000

I've tried to keep my Home theatre purchase simple and cost effective as I was restricted to a fairly tight budget.

All the components where bought over several years of saving.
I chose the Screenplay 5000 for brightness and sharpness over the Panasonic AE700. It was a tough decision between the two units. DLP projectors were out of the question as I am vulnerable to rainbow effects. The Dolby Digital amplifier was a low budget unit, I felt spending more money on speakers was a better way to go. Once I heard the Tannoy's, I new these speakers where the right ones for me.
The subwoofer was a kit I bought from Jaycar Electronics, It comprises of 2x 12" subwoofers (placement Isobaric)driven by the Playmaster amplifier 'configured in Bridge mode' which was also in kit form. The dynamic sound range this subwoofer brings to this sound system is incredible. Very happy chap.

Before I go on with my home made screen, I want to mention my HTPC. A HTPC was a better choice for me than buying individual pieces of hardware, as it could play just about any video format and also record and view HDTV, all this for under a $1000. Connection to projector is via VGA, Amp via S/PDIF. It also simplfied the amount of cables required to connect up the system.

Ok! Now back to the home made screen. This is my pride and joy as it was totally fabricated from materials bought from local Hardware, Electronic and Curtain stores. Because of my low budget and therefore could only buy a low end projector, I noticed that the blacks, although they appeared by perception blacker in the video area, the horizontal bars always appeared slightly misty white in movies that used formats other than the 16:9. I decided to give it a go and see if I could build a motorised screen that can hide these horizontal bars by adjusting curtains via remote control.

Following are the pictures of my project with simple explanations on how it was done. Please exclude the crap laying around in the HT room!

Pic 1: Frame was made from Pine timber and mitred together.

Pic 2: Another frame was then attached to the perimeter of the first frame to form a cavity about 7cm high to hide all the mechanics and electronics.

Pic 3: A frame identical to the first was then made and mounted with hinges on top, this can now be opened with ease to make adjustments to the mechanics and/or electronics.

Pic 4: The screen was painted in matt black and mounted straight on to the plaster wall, which was also used as the actual screen painted in vivid matt white to keep costs down.

Pic 5: The curtains are driven up and down using geared down motors and lace rods.

Pic 6: The top curtain was easy to lower and raise as a normal blind would operate. But the bottom curtain was a little more difficult to do. I used elastic bands on both sides of the screen, tensioned from the end of curtain to the top of the screen, This pulled the curtain up as the motor unwound the fabric from the lace rod. It's a little hard to see in the photo.

Pic 7: This shows the 8 channel infra red receiver pcb kit. I'm using 4 of the channels only, configured as 2 H-bridge circuits to drive the motors in both directions. I also placed some aluminium rods to guide the curtains and micro switches to disable the motors when the curtains reached there inward limit and home position. Sorry for the bad photo.

Pic 8: The screen finally finished and the curtains drawn to black out the horizontal bars. I used the flash on the camera so the curtains can be seen. I plan to paint the room in a dark colour at a later stage.

Pic 9a & 9b: These pics show the difference it makes with and without the curtains. You can really see the difference if you load the 2 pics in a picture viewer and switch quickly between the two.

Pic 10: With the curtains retracted I can also watch 16:9 format movies.

Good luck if you decide to make one.. It is a little tricky but if your handy it won't be a problem.. The pictures do not always do it justice. It really is amazing and the difference it makes to contrast is significant when viewed in person. If you need more info I will post more pics and info here in time..

Thanks to Projector Central for helping me make an informed decision on choosing the right projector for my application.

Cheers
George Kansas

Attachments:

Pic1.jpg

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Pic2.jpg

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Pic9b.jpg

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Pic10.jpg

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Joined: Feb 17, 2009
Posts: 10
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Hi, it seems too good, thank you very much for sharing this information.
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Joined: Mar 29, 2010
Posts: 1
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great job. Is there anyway you can explain in detail how you did this whole project? I mean I am not as handy as you and do not have much knowledge about electric motor setup etc. it would be great if you can explain in detail how you did it? Thanks even if you do not have time to do it. Atleast i got idea from your post. great job again.
[Edited by hphp on Mar 29, 2010 at 2:13 PM]
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Joined: Nov 19, 2008
Posts: 4
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Hi! And many thanks. I would like to explain in every little fine detail but it would just take too long and none of it is documented. It all resides in my head. And I'm not at all that good at explaining things. But I will try my best and help anyone whom would like to try and build one.

It all began with some weird ideas of how I would build this screen, in the end it came down to trial and error to get the mechanics working correctly. Especially the bottom masking curtain, this was the trickiest part. What I can show you for now are some close up pics of the hardware and explain things over time as you may require more assistance. If you require greater resolution pics , send me your email. By the way sorry for the late reply!

Some pics are blurry. So if you require greater clarity I can retake them as I have updated my camera since then.

Also check out my other topic:
Final Stage: DIY Automated Horizontal Masking Screen.

I will check back here on a weekly basis. Good Luck!

Attachments:

Bottom Curtain hardware

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Infra red kit invoice

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Infra red PCB mounting position

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Bottom hardware close up

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Top curtain hardware

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motor catalog

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member
Joined: Nov 19, 2008
Posts: 4
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Missed one pic!

Attachments:

Bottom Curtain hardware close up

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