You may charge your mobile phones now just by walking, for Canadian researcher Max Donelan has invented a gadget that produces power from the human knee.
The knee power generator is capable of producing 2.5 watts of electricity per leg, which is enough to power five cell phones.
It is not practical at the moment because it is too heavy to be worn all the time, and looks very awkward. But still, it apparently encourages the idea that of a little bit of energy scavenging from cheap or free sources is possible.
'It's a very hot topic. Energy scavenging has been around for years, but because of the fuel crisis, everyone from big companies to small ones is looking to utilize it,' the Environmental News Network quoted Marc Poulshock, president of Thermo Life which produces devices that draw thermoelectric energy, as saying.
Scientists even believe that vibrations created from environmental motion, such as from a bridge or dance floor, may serve as free source of electricity generation.