CurtPalme.com Home Theater Forum

[perisoft]

I'm starting to nail down the final bits in my HT, and would like to come up with a way to do masking for 2.35 movies. I'll have to build my own kit - which will probably consist of a roll down thing which will drop the mask over the screen.

It would be nice to be able to control this from software, and I can probably manage that via serial / parallel output. But it'd be REALLY nice to have the mask drop only when a 2.35 movie is playing.

It'd also be nice to (eventually) be able to dim lights based on whether a movie is playing, etc.

Does anyone know of any tools out there that can do this kind of detection and tip off a program / script of mine, without my having to resort to rolling my own memory snooper or so?

[prover]

For the first part of your question (the design of this roll down thing? ) I could give you some input. Also for the control of the "roll down thing" over IR. What I never did is coupling the control with the player device. If you want I can post some detailed information.

prover

[perisoft]

[prover]

ok Iw will come back tomorrow with some detailed description. I think I have a couple of good pictures taken...

prover

[ecrabb]

Do some searching at AVS... I've seen several nice DIY solutions over there, including good mechanical designs with rollers and counter-weights, circuit designs for controllers, etc. With as much work as people have already done, you shouldn't have to do too much design engineering.

SC

[CRT_Ben]

That's what I love about this forum - no one person has done everything, but ask a question and almost certainly someone has some experience! I'm interested as well because I want a masking system when I build my HT.

[prover]

here is my solution for the mechanical part (the elctronic part follows):

I installed a hollow aluminium spindle with a step motor behind the screen (actually for roller blinds and very cheap).
I fixed 4 ropes on the spindle unsing the holes on it. These ropes are attached to the mask (two frames for upper and lower masking) and are redirected twice by two reels respectively (8 reels all together). In the picture above you see the reels for the first redirection (perpendicular to the screen -> parallel to the upper edge of the screen). In the next picture you see the reels for the second redirection (parallel to the screen upper edge -> parallel to the screen right and left edge):

The ropes are winded in opposite directions on the spindle. When the spindle is rotating counterclockwise the upper mask frame is moving downards while the lower mask frame is moving upwards for cinemascope masking:

For clockwise rotation of the spindle the frames move in the opposite direction for 16:9 mask:

[prover]

Now the elctronics part. For the control of the mask and a couple of other things I use a diy infrared receiver with 8 relais outputs, that means you can control up to 8 different devices with it. I have realized the circuit using a simple stripboard, here is a picture (when I have some time I will make a printed circuit board ):



I bought a small chassis for the whole stuff and this is the result:



The circuit understands RC5-codes (standard infrared codeing developed from Philips). The heart of the circuit is a programmable PIC-chip where you can upload the RC5 codes you want to use. Almost every programmable remote control today uses RC5 codes. You can upload the codes using a small serial device that can be pluged in near the chip.
The chip has 40 memory blocks free for programming (plenty space for HT usage).
The circuit works really fine and reliable.
You can find more information under:

http://www.bitmonster.com/ir/index.html

Unfortunately this is a german URL but you can find there everything needed to realize the circuit (firmware for the chip, windows software for uploading the codes and the firmware to the chip, the circuit plans and a complete parts list).
If you need some help for reading give me a hint

[Nashou66]

Prover you should post this in the Home theater construction thread as a stand alone post so we can find it if and when we want to build our own masking system.


Athanasios

[prover]

Sure, good idea.

prover

[perisoft]

Awesome stuff - the only problem with replicating it is that I need mine to suck right up to within 8" of the ceiling when not in use, because there's a door behind the screen wall that we use... that damned door really complicates my life!