Now that more and more smart phones and MP3 players have touch-screen interfaces, people have grown accustomed to interacting with gadgets using only taps and swipes of their fingers. But on the 11th floor of a downtown Manhattan building, New York University researchers Ilya Rosenberg and Ken Perlin are developing an interface that goes even further. It's a thin pad that responds precisely to pressure from not only a finger but a range of objects, such as a foot, a stylus, or a drumstick. And it can sense multiple inputs at once.

The idea for the pad occurred to Rosenber­g, a graduate student at NYU, a few years ago when he was working with a conductive polymer called force-­sensing resistor ink, which is often used in electronic music keyboards. When pressure is applied to the ink, its molecules reorient themselves in a way that alters its electrical resistance, which is easy to measure. Rosenber­g originally used the ink to create sensors that could be embedded under tennis­-court boundaries to automate line calls, but he wondered if it might be the basis of a good multi­touch interface for computers. He began collaborating with Perlin, a professor in NYU's Media Research Laboratory, to make a pressure-sensitive touch pad to replace a computer mouse.