A team at University of Washington has built a small device that correctly interprets hand gestures 90% of the time, so it can be used to control your television or other devices - and it's powered by the energy fields around us.
There’s energy all around us in the form of TV, radio and WiFi signals. Develop a device that doesn’t need much power, and you can harvest enough power from thin air to cut out the need for a battery entirely.
Better yet, it cost them about a dollar to build.
