Some ten years ago, researchers at the Georgia Institute of Technology in Atlanta demonstrated a way to harvest vibrational energy. Their device was simple—essentially two sheets of material placed in contact and then flexed. If the materials are carefully selected, this process transfers charge from one sheet to the other, generating a voltage between them, a phenomenon known as the triboelectric effect. Flexing the material in the other direction reverses the polarity.
The resulting device--a triboelectric nanogenerator-- is today the subject of intense study. The hope is that it can power a new generation of internet-connected devices by harvesting energy from almost any mechanical vibrations or movement.