The Apple Motion Sensor As A Human Interface Device
"I described the working of the Apple Motion Sensor (AMS), a feature of the PowerBook line of computers, in previous document called The PowerBook Sudden Motion Sensor". As I noted earlier, my original reason for investigating the AMS was to fabricate some interesting programming examples for my forthcoming book on Mac OS X internals. The discussion of the AMS generated a substantial amount of interest — perhaps more than I had expected. It is quite interesting to observe how one's fantasy is tickled by abnormal ways of doing the normal." Read more here.