Neil writes – “Here is an inexpensive way to create a three dimensional pointing device. Take a working mechanical wheel mouse (the type with a scrolling wheel). Remove the ball. Drill some holes in the sides and run a string into the mouse, around the horizontal roller, and out the other side. Reroute the sensors for the vertical roller and the scroll wheel to a pair of external sensors. “ [via] – Link.
DIY 3D Mouse