[Techb] had a friend who was paralyzed after an accident and could no long use a computer. He rigged up an amazingly simple mouse interface using python to implement infrared tracking. The controller was built from an old hat by adding an IR LED and wireless mouse modified so that the button could be clicked by the user’s mouth. A webcam with exposed film used as a filter can track the IR LED and take input from the wireless mouse buttons.
This setup, which draws inspiration from Wii Remote white boards, is much simpler than the Eyewriter (and doesn’t shine an IR LED into your eye). Although [Techb] wants to add facial recognition to the system, there’s something to be said for such a simple implementation.