We're all intimately familiar with the backs of our hands, so why not use them as a haptic interface to control our gadgets? That's the idea behind the device pictured above -- a nifty little wrist sensor that turns your paw into a flesh-toned trackpad. Designed by Kei Nakatsuma, a PhD student at the University of Tokyo, this contraption employs infrared sensors to track a user's finger as it moves across the back of a hand. These movements are mirrored on a wristwatch-like display, thanks to seven IR detectors and a set of piezoelectric sensors
