This video of a 3D input interface for mobile devices shows how researchers are looking into using the space just above your cellphone or mobile device. Using a special camera and software, researchers at the University of Tokyo are working toward gesture-controlled interfaces.
(Gesture-Controlled Phone Video)
"Using a high-frame-rate camera, the fingertip moving fast near the camera can be stably tracked and the interface realizes wide operation area. The binarized fingertip image is used to estimate its 3D motion and posture."
I'm not alone, fans of Douglas Adams have been waving their hands at devices ever since reading about gesture-controlled devices in his 1979 classic The Hitchhiker's Guide to the Galaxy:
The machine was rather difficult to operate. For years radios had been operated by means of pressing buttons and turning dials; then as the technology became more sophisticated the controls were made touch-sensitive--you merely had to brush the panels with your fingers; now all you had to do was wave your hand in the general direction of the components and hope.
(Read more about Adams' gesture-controlled devices)
Click carefully with your mice to learn more about gesture interfaces: