Scientists at the University of Auckland, New Zealand have developed a wearable electromagnetic energy harvester that could take vibrational kinetic energy generated by the wearer and convert it into usable electricity for medical devices.
EE Times explains:
Comprising a snake-shaped silicone cantilever, a coil, and an NdFeB magnet, the device has an approximately 6.6-Hz resonant frequency and -10-mVpp output when tested with an acceleration of 0.3 g. The output increases to approximately -40 mVpp when tested at 1.5 g — similar to the acceleration experienced when a person walks. The device ways only a few grams.
In the past, researchers have developed lightweight energy-harvesting devices that could only produce a few millivolts from normal human activity. This amount of energy is not enough to drive charge even a low-power medical implant.
The researchers managed to miniaturize the technology that mimics the basic functionality used to generate electricity in power stations. Jiayang Song and Kean Aw, both of the university, attached the cantilever to a conducting metal coil containing a powerful magnet. Current is generated when a conductor travels through a magnetic field.
Other researchers are working to harvest energy from the pulse of the beating heart. Led by professor John Rogers, PhD of the University of Illinois-Champaign has developed a thin silicone-encased energy harvester that can be attached to the heart. The scientists demonstrated the feasibility of the technology in anesthetized cows and sheep, showing that it can produce up to 1.2 μW/cm2 of power.
