As medical devices are becoming more energy hungry thanks to new capabilities, batteries that are used to power them are not keeping up. Lithium ions have essentially plateaued the development of new batteries for now, but a way to overcome this challenge is to generate power continuously and feed it to hungry devices as needed.
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. The device, called PediPower, produces about 400 milliwatts in laboratory tests, enough to charge a battery for some limited applications.
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The PediPower hits the ground before any other part of the prototype shoe. A lever arm strikes first. It is attached to a gearbox that replaces much of the shoe’s sole and turns the gears a little with each step. The gears drive a motor mounted on the outside of the shoe that generates electricity to send up to the battery.
“It may be worth looking into having both the heel and the ball of the foot produce power, especially if this shoe could be used while running,” Armada said.
The students expect the project to be picked up by another team at Rice in the fall, with the hope they can refine the materials, shrink the size and boost the power output, all of which will get PediPower closer to being a commercial product.
“If we could prove that we could produce some usable power, store it in a battery and discharge that battery on a mobile device or an MP3 player, then we could prove this device works,” Armada said. “Now the next team can come in and make it smaller and lighter without sacrificing power.”
Press release: Prototype provides pedestrian power…