A team of engineering students at Rice University have been tasked with developing a new device that can harvest the body’s motion to produce useful electric power. In the process of researching where it’s best to gather the energy they settled on the heel of the shoe, which is normally designed to absorb the shock and finally transfer the energy into heat that is lost forever. They instead developed a mechanical heel that spins a small motor, that in turn generates electric power.

Considering that the iPhone costs 41 cents a year to power, this is a super interesting, and potentially useful way to harness our natural energy to power our external brains.