As we've seen, it doesn't exactly take all that much
to whip up a homemade multitouch
system, but that doesn't make Bridger Maxwell's science fair project here any less impressive, which wraps everything into a fairly tidy, OS X-based package. Like other similar systems, this one relies on a slew of LEDs (28 of 'em in this case), along with a webcam modded with an IR filter, and piece of acrylic and a spare LCD screen for the surface itself. To show it off to its fullest potential, Bridger whipped up an app of his own for OS X that lets users flip through XKCD
comics with suitably fancy graphics thanks to OS X's Core Animation. There doesn't seem to be any video of the rig in action, unfortunately, but you can find plenty of pics of the entire build process at the link below.
[Via TG Daily