This looks pretty cool…Leap Motion. Seems like it’s vision based although there doesn’t seem to be much details available. Either way, it looks pretty neat although they don’t have anything for Linux yet. Just Windows and Mac I think.
A good explanation of the POSIT algorithm for beginners…used it in my final year project to find a mapping between 3D data obtained from the Kinect and the 2D projection from a pico projector.