Mini-Multitouch Interface

Step 3 Build the touchsurface frame

This step covers the building of the frame that will house the Lexan, as well as the preparation necessary to mount the LED lights in the frame.

The best material I found for the frame is 'Tile Divider', which comes in 6- to 8-foot strips and can be purchased in the molding section of most home repair stores. See the images below for a visual description (rather than try to explain here!).

The frame will fit the Lexan very closely, so you can cut the Tile Divider exactly to size: cut two 8-inch strips, and two 10-inch strips. Once the strips are cut, you should use a T-Square to cut the ends of the short strips to bevel inward at a 45% angle. This will make them fit neatly and snugly as a frame around the Lexan.

You will be mounting the four LED lights on one 8-inch side of the frame. They need to be mounted so they are touching the Lexan through holes in the strip, and spread out evenly along the edge.

It is important to place the holes near the top of the strip, as shown below, so that the light shines into the edge of the Lexan only, and NOT down onto the camera below. Mark the locations of the four holes at about 1-inch, 3-inch, 5-inch and 7-inch along the edge of one 8-inch Tile Divider strip.

Because the Tile Divider is made of soft plastic, you'll need to drill the holes in several incremental sizes to avoid bending or warping the plastic too much. First, drill a small hole (1/16"), then drill one a little larger (9/64"). Finally, drill a 3/16" hole, which is the ideal size for the LEDs to fit through.

Comments

[shadowsrevenge]

When modifying the webcam is it possible you could brake the computer?

[FarMcKon]

Not at all, there is 0.001$ chance of breaking the computer. Even if you work on it plugged in (DON"T do that) you would at most ruin the one USB port you are plugged into. Now, having letting something fly across the room because you were prying too hard, that is possible. Don't work on this right next to you LCD monitor, for example.

[francoisp]

As far as I understand it, the plastic frame is only there to keep the infrared light inside the lexan while it spreads ? So couldn't we simply use sume duct tape / black electrical tape to cover the side have pierce a small hole on a small part of the tape ? Am I wrong ?

[FarMcKon]

The frame is there to keep the LED's mounted at a decent angle, and so the whole thing can be mounted in/on a table. I think you could use tape, but I'm not sure how well that would hold up once someone starts using gestures, etc. That much hand motion was even problems with my plastic frame using lower quality glue. I upgraded from hot-glue to crazyglue after LED's kept getting knocked off after 15-20 of playing around and using gestures.