A Vision-based Input Interface for Mobile Devices with High-Speed Fingertip Tracking has been created and demonstrated by researchers at the University of Tokyo.
A single camera tracks the movement of your fingertip in front of the screen; a high frame rate is required, but the device can also track the orientation of your finger. Shaking your finger at the device is counted as a "click".
Will the multi-touch give way to the finger gesture? Watch this concise explanatory video and judge for yourself.
A loud clatter of gunk music flooded through the Heart of Gold cabin as Zaphod searched the sub-etha radio wave bands for news of himself. 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. It saved a lot of muscular expenditure, of course, but meant that you had to sit infuriatingly still if you wanted to keep listening to the same program.
Zaphod waved a hand and the channel switched again.