Check out this video tutorial on how to make a cheap multi-touch pad like in the MacBook Air. Yes, that's right... you can make your very own multitouch, finger-sensitive touch pad for your computer. This is definitely the cheap way to go to make a Multitouch Mini (MTmini), with a maximum of fifty bucks down the drain. This multitouch touchpad (or trackpad) is easy!
*Piece of Clear Flat Sturdy Material (Glass, Acrylic, or Plexiglas)
*Paper (Printer Paper, Tracing Paper, or Any Other Paper)
*Webcam or Video Camera (Philips SPC900NC)
*Computer (Dual Core Recommended)
*Optional Picture Frame
Building a small portable multitouch pad will allow you to test software and experiment on a smaller scale while building your full table or when away from your multitouch screen. This uses Front Diffused Illumination, with normal ambient light (infrared not required or needed) and a normal off-the-shelf webcam (IR filter can still be in place).
For this to work, all you need is a room with (at least) some light. The results will be best when the room lighting is even (no bright lights shinning from one direction onto the multitouch pad).
When you place you fingers on the surface, shadows are created where your fingers are. The webcam sees these shadows and sends the image to the tracking software which tracks the shadows as they move around. It's really that simple!