French physicists Ros Kiri Ing and Mathias Fink have figured out how to turn any rigid surface into an interface for electronic systems. The technology -- which the pair hope to commercialize via their Paris-based startup, Sensitive Object -- uses one or two inexpensive accelerometers to detect finger taps on, say, a storefront display window or a keyboard drawn on a blackboard. A computer chip calculates the precise origin of each tap and translates that information into mouse clicks and keystrokes. Users might use the technology, for example, to "click" on a storefront mannequin's hat to learn its price. Ing says the technique has advantages over other user interfaces under development because it can work with a surface as large as four square meters, and the number of "keys" can reach 544.