Everything from industrial equipment to the human body loses
some of the energy it uses to things like heat and vibrations.
The ability to harvest some of this energy is usually pretty
limited, as small heat differences and weak movements are
difficult to concentrate into significant amounts of useful
energy. But even an inefficient conversion can be sufficient to
provide power for small energy-efficient devices, such as
medical implants and short-range transmitters, so researchers
are working on developing materials that can convert
environmental noise into small amounts of useful energy. In a
recent example of this work, researchers have demonstrated that
they can print a bio-compatible device that can harvest the
stress created when it's flexed to produce over 10 nanoAmps of
current. The device relies on the piezoelectric effect. A number
of crystals, when stressed, create small amounts of current.
That stress doesn't have to be extreme—the vibrations, flexing,
and twisting that normally occur in many situ