Girder and other HTPC related questions

[lovingHDTV]

For all the Girder experts out there I'm hoping to get some advice.

I have made a motorized vertical masking system for my hometheater. Basically there is a microcontroller that is controled via switches, or serial commands. I can send a serial command to the controller from the computer (using a terminal program right now) to move the top or bottom curtain up and down to mask my screen.

I would like to interface this with my remote. I believe that I can use Girder to do this. I'm already using Girder for my remote control in Sage, so I thought that I could use it to also send serial packets to the screen. Is this possible? If it is, could I also set it up to recieve the packets via TCP/IP then retransmit them via serial?

Secondly, I'm looking for a program that could determine the aspect ratio of the playing media and report it to me. I would like to be able to get this info, then move the curtain to automatically mask for the reported ratio. I'm using the optical shaft encoders, from a mouse, via the PS/2 interface to my microcontroller, so I can know the positon of the screen. I'm thinking that with calibration I can tell it to move to 1.85, or 2.35 and it will move the masks for me. Can DVDSpy or something like that do this? Can Sage report the aspect ratio? It can manipulate it, but I don't know if it can report what it detects.

thanks for the help,

[mostlyfodder]

one question about the aspect ratio-- i've never noticed sage to detect it. i always have to change it myself when switching from dvd to TV.

- mf

[stanger89]

OT (sorta) got any links for that masking system? I've got to build one myself.

[lovingHDTV]

I've not made up anything, but I could describe it and take some picts if you are interested.

Hmm, that did not come across like I wanted so here is a synopsys.

I have a 16:9, 120" diagonal screen the width is right around ~108" I believe. I made it from two 5'x5' sheets of birch plywood covered with Parkland Plastic and is fixed mounted to the wall.

My masking system is a vertical masking system as I have not concerned myself with masking 4:3 material.

I made the masking system using electric windshield motors, one for each screen, top and bottom. It is only attacked to the wall at the top. The top roler is made of 1 1/4" EMT conduit with an oil impregnated brass bushing held to the wall with a wooden block. The top curtain is wrapped around this roller and I have a 22 tooth sproket connected via a chain to the motor. When the motor turns the top roller moves the curtain up and down.

The bottom curtain hangs from a second roller made of 3/4 black steel gas pipe and is inserted through the top roller and thus through the same brass bushing. The curtain hangs from the chains over a 22 tooth sprocked hooked up to a second motor.

That is it in a nut shell, easy to attach and remove from the wall and totally self contained.

More details if you need/want them.

[stanger89]

I suppose I was more interested in the electronics/control mechanism I've got to figure a way to mask my 41x96" screen

[lovingHDTV]

Ah, that part

As previously mentioned I use two windshield wiper motors, from here:
http://www.allelectronics.com/cgi-bi...171&type=store

I removed the lever and put on a sprocket to drive the matching sprocket on my masking rollers.

I drive the 12V DC motor with the following H-Bridge driver (NMIH-0050):
http://www.newmicros.com/index2.php?...cat%3Dh_bridge

From this board:
http://www.bdmicro.com/mavric-iib/

with some optical switches used for home/limit positions (can't find the link).

I used winAVR to program the microcontroller and it has a couple dpdt (on) off (on) switches that can control the mask and move it in either direction. If the home or limit switch is set, then the maks stops moving. It will also read from the serial port and can recieve commands from the computer to that will move the mask also. The manual switch has priority over the serial control.

Do you want to do 4-way masking, vertical or horizontal masking? I like my vertical masking system because it will work for any screen up to 110" wide. Cost is very reasonable and I could build it again in a weekend.

hope this helps,

[stanger89]

Originally Posted by lovingHDTV

Do you want to do 4-way masking, vertical or horizontal masking? I like my vertical masking system because it will work for any screen up to 110" wide.

I'm Contant Height (2.35:1 screen) only horizontal is needed. I'll have to keep this in mind.

[Menehune]

Originally Posted by stanger89

I suppose I was more interested in the electronics/control mechanism I've got to figure a way to mask my 41x96" screen

I have a "cardboard" mask that clips onto my 4:3/16:9 monitors at work. The monitors have electronics to shrink the height of the picture, but the manufacturer provided this mask as well. Probably cost $500 bucks for that piece of plastic