All living species generate sources of mechanical energy. They do this by stretching muscles, walking, running, heart beats, and blood flow. Scientists at Georgia Tech hooked up a piezoelectric nanowire to a hamster in order to convert biomechanical energy into electricity. Zhong Lin Wang, a nanotechnology expert at Georgia Tech stated that nano-devices require so little energy that power from sound waves and muscle twitches could power them.
Wang took the nanowire from the hamster and connected it to an oscilloscope. As the hamster ran, it generated 70 millivolts of power. The energy stopped for a second when the hamster licked itself instead of continuing to run on the wheel.
Researchers could build all sorts of tiny sensors using this concept. They could use the sensors to monitor the environment, check the body for cancer and excess insulin levels. However monitoring all of these activities requires very reliable power supplies.
The nanowires are made out of zinc oxide. Energy flows through those wires when they are stretched and compressed. When the hamster ran, the nanowires were bending and that sent electrons through the wire and to the power meter.