Thursday, April 17, 2008

The Finished Table

My first table prototype is finished! Here is a picture of the table after I got it wrapped in vinyl:

I would have a better picture of it in action, with the application running, but the backlight is still pretty terrible and the pictures turned out pretty bad.

Disaster Strikes!

So this whole project was created for science fair. The night before the Central Utah Science and Engineering Fair, my table decided to stop working. The blobs of light were significantly dimmer, and were not bright enough to be picked up by OpenTouch. After some investigation, I found that half of the LEDs were not lit. This was because I had all of my LEDs in two parallel circuits, so one blown out LED will take them all out. Hopefully, only one LED would be blown.

Taking the frame apart to replace the LED was not going to be a simple task. Everything was covered in black vinyl and electrical tape, and it would be difficult to remove any strip of LEDs without messing everything up, but it had to be done. After about an hour of taking things apart and looking for anything out of the ordinary, I finally tracked down the broken LED and replaced it.

My FTIR Frame, Partially Disassembled :(

Here is the Culprit. If you look closely, you can see the burned out look that gave it away.

While it was already torn apart, I decided to try and improve my FTIR frame. Three sides of my plexiglass had LEDs, but the fourth side was left bare and was releasing a lot of infrared light. I fashioned some reflective tape out of tinfoil, spray adhesive, and clear masking tape. Although it was probably due to the late hour, I felt like MacGyver at this point.

I then applied this reflective tape to the top edge of my plexiglass and reassembled my FTIR frame.

Fortunately, when everything was restored, the FTIR frame actually gave brighter blobs than before! I only lost two hours of sleep...