Tuesday, July 1, 2008

Prototype Table Almost Completed!

Well, it's been a while since my last post. I've been very busy working on this table, and it's about 75% finished! I just need to mount the switches, fans, audio amp, and make final adjustments with the projector and camera mounting. Then I need to throw some side panels on it (with 8" speakers mounted). Also I need to put some tracing paper between my silicone compliant surface and my rosco projection material so the blobs will be more accurate. I also need to cover the acrylic frame and LED's with something. I will be posting a video of the table in action as soon as I can get a chance to make one and after I do more calibrating of the system.




The 2 main snags that I have hit so far are the projector display size and the compliant surface. First when doing the compliant surface I decided to try the Cheap method of thinning silicone caulk with Toluol. Not only was it messy and it didn't work, but It also led to cracking along the edges of the acrylic! Apparently as it cures it shrinks and can cause the glass to crack. Not only that but since I flame polished the edges of my acrylic for the led's to shine into it better, the toluol had a bad reaction causing the cracks along the edges. Not sure if it was the silicone shrinking or the toluol reaction with flame polished edges that made the cracks...possibly a combination of both. I also scratched my acrylic while I was trying to level off the silicone with a giant putty blade (possibly the dumbest thing I've ever done). Eventually I got some Sorta Clear 40a to and poured it onto the acrylic. I should have done that from the beginning.

The snag with the projector is that my table is basically slightly too short for the projector's minimum throw distance to fill my 44" screen completely. In other words the projector requires a little more distance from the screen to make it fill the screen (even though I'm using a mirror, the projector is not quite far enough away from my screen). One other snag is that I built the top of the table first (to hold the acrylic). I decided to round off the corners. I forgot to redo my measurements after that (before building the table). So the top is just a hair too small for the table, but it still works fine - just doesn't look good. Oh well, learning is half the fun!


After much thinking and experimenting I finally made a projector mount that works great. I used plywood and some extra hardware I had laying around.

For wiring the LED's I found some led PCB strips that worked out perfectly. I got them from this ebay store. I wired them with a 47ohm 1 watt resistor for each set of 5 led's. I used this led wizard to show me how to wire it all.