My multi-touch prototype
By Erik van Kempen | April 21, 2007
Everybody with the slightest interest in user interfaces should watch the well-known video of Jeff Han at TED. Every second of this video surprised me. The day after I first saw the video, I was actively searching for more information about the used technology. Several other people managed to build a multi-touch screen, so I thought I could do it too. I 'designed' a small prototype, the size of a normal piece of paper (A4).
Design
I rendered some pictures of the simple design. I wanted the LEDs and the rest of the electronics to be hidden in the frame, so only a small power cable would stick out of the frame.
Budget
I decided I wanted to spend not more than $15 (or €10,-), so everything needed to be cheap. The acrylic used is 200 x 300 x 4mm and cost $2 at the local DIY store. I needed some wood, multiplex, which cost $2. Of course I needed to buy twenty IR LEDs for every, which cost $0.15 a piece and $3 in total. My old web cam will be the 'eye' and cost me $10 when I bought it a few years ago, but I didn't use it so this one doesn't count. So the total cost of this design is $7, without the cam and without a projector (which I can't afford :-( unfortunately)
Yesterday I drilled the holes in the two wood sides, so the are ready. The only thing I need to do is solder all the LEDs and resistors together. If it's all finished, I'll post some pictures of the result.
I'm currently working on the software too. I've run some successful test cases for the blob detection algorithm. :-) I'll probably post an update about that later this week.