It is possible to use your PowerBook as an input device, according to author Amit Singh, who is working on a book about Mac hardware. In the more recent revision to the PowerBook line, Apple Computer added something called the Apple Motion Sensor (AMS), a technology makes it possible for your PowerBook to lock down its hardware in case of a drop. Mr. Singh has figured out some far different ways to use it as an input device in place of your mouse or keyboard.
In other words, using data from the AMS, one can get coordinates based on the physical positioning of the PowerBook itself, and Mr. Singh can use that data as user-input. Earlier sample applications he published include software that displays a picture of your PowerBook that corresponds to its position, and an app that shows a bicycle wheel that rotates itself in sync with your PowerBook.
Mr. Singh has posted some new software called AMS2HID that allows any game to use your PowerBook as a controller.
"AMS2HID allows you to play games using the PowerBook itself as a controller," he wrote, "the computeris motion in physical space provides input to games. As noted earlier, any game whose primary controls are directional should work well wit AMS2HID. This includes many car-racing or driving games where ilefti/iright, iupi, and idowni can be used for steering, acceleration and braking, respectively. Flight simulators and maze-based puzzle games are other likel candidates."
Better yet, he provided what he thinks is the perfect candidate for the idea, Neverball, an Open Source game for Mac OS X and other platforms that is inspired by the classic arcade game Marble Madness. Tilt your PowerBook one way, and the floor in Neverball tilts the same way. Tilt it another, and so moves the floor, allowing you to control the ball in Neverball by holding your PowerBook and tilting it in real-time.
Mr. Singhis demonstration of Neverball
The full article posted at Mr. Singhis site has all the details, including a lot of technical explanations that some folks may want to skim through. We got the link from a Slashdot article.