Microsoft Research and Carnegie Mellon University have teamed up to to create an armband that projects a touchscreen interface directly on to your skin. The best part? Skinput knows which part of the body you've tapped, based on the sound that's matched against skin, muscle or skeleton.
Via Daily Mail,
"Skinput can be used to control audio devices, play simple games like Tetris, make phone calls and navigate simple browsing systems.
The gadget effectively turns your arm into a touchscreen surface by picking up various ultra-low sounds produced when you tap different areas.
Different skin locations are acoustically distinct because of bone density and the filtering effect from soft tissues and joints. The team then used software that matched sound frequencies to specific skin locations.
The prototype then uses wireless technology like Bluetooth to transmit the commands to the device being controlled, such as a phone, iPod, or computer..." (Read More).