Calling all couch potatoes: This finger wrap can let you power electronics while you sleep

The device also generates extra power from light finger presses--so activities such as typing, texting, playing the piano or tapping in Morse code can also become sources of energy.It derives most of its power from sweat produced by the fingertips, which are 24-hour factories of perspiration. It's a little-known fact that the fingertips are one of the sweatiest spots on the body.

The device is a thin, flexible strip that can be wrapped around the fingertip like a Band-Aid. A padding of carbon foam electrodes absorbs sweat and converts it into electrical energy. The electrodes are equipped with enzymes that trigger chemical reactions between lactate and oxygen molecules in sweat to generate electricity.