EVOLUTION OF VISUAL AND SOUND

John Cage & Merce Cunningham, Variations V, 1965
John Cage and David Tudor settled on two systems forthe sound to be affected by movement.For the first, Billy Klüver and his colleagues set up a system of directional photocells aimed at the stage lights, so that the dancers triggered sounds as they cut the light beams with their movements. A second system used a series of antennas. When a dancer came within four feet of an antenna a sound would result. Ten photocells were wired to activate tape-recorders and short-wave radios. a student at the University of California, San Diego is researching on and developing a Multi-user/Multi-touch musical interface.pretty interesting.
here's his blog
He investigates the idea of the interactive interface purposed in a more complex way from Microsoft, the Microsoft Surface
Microsoft Surface website