Scientific American 60 Second Science

A device called a rectenna is designed to capture energy from y pi signals and turn em into direct current electricity. Using typical home y fi signals, it spits out about forty microwats enough to light up a simple l d display or power a bio censor. It's not enough juice for power hungry smart watches and smart phones just yet, but Shu jong says their next goal is to build an array of rectennas to power larger devices.