Dennis Siegel, a student at the University of the Arts in Bremen, Germany has built what he calls an electromagnetic harvester—it converts electromagnetic fields in the immediate environment into electricity to recharge a common AA battery. He’s won a 2nd place award in the HfK Bremen Hochschulpreis 2013 competition for Digitale Medien, for his efforts.
Electromagnetism is all around us of course. In addition to natural sources, such as lightning, it’s also given off by virtually every electronic gadget, device or machine humans make. Siegel (and many others) have noted that the electromagnetism around us all could be converted to electricity and used for some purpose. The problem of course, is that the comparatively small amount of it in the air around us isn’t enough to make much electricity—the device Siegel built takes up to a day to charge a single AA battery. But that’s not reason enough to not build and use a device, as he has demonstrated. He’s added electronics to give the device the capability of capturing electromagnetism in two ranges—one below 100Hz (electrical mains, etc.
( via phys.org )