Yu Jiang has put together a sweet robotic arm that track’s his arm and hand movements pretty well. The arm its self is constructed using a Lynxmotion rotating base, servos, raw materials, and some aluminum scissors and spoons for the fingers. On the tracking side I have to assume the 3D tracking is done with the Leap Motion control device, the arduino is controlling the servos and node.js is used to tie it all together.
Here is a link to his build instructions which is only part 1. Part 2 will cover the software more but in the mean time he does have the source code up on github for your viewing pleasure. Pretty neat hack, I would really love to see 2 of these going at the same time tracking both hands.
*UPDATE* Part 2 is up.