Microsoft and Carnegie Mellon researchers are discovering ways to make skin an input device for technology. These bio-acoustic sensors and projecting arm-bands are expected to be used as the input devices, in hopes of getting an advantage in technology.

According to the NPR, the projectors beam images onto...your forearm — when you tap on them, ripples run through your skin and bones. Sensors pick up on these waves, and convey those commands to your MP3 player or other device.