ASSIST is developing devices that harvest energy from human motion. The approach has required a number of advances, including the fabrication of bimorph lead zirconatetitanate (PZT) thin films with a high figure-of-merit (FoM), development of a technique to produce thick PZT layers on nickel foils, and optimization of the mechanical system.
An energy harvesting system that captures power from body motions can help power a variety of body-worn sensors. We are currently pursuing wrist-worn harvesters to extend the battery life of ASSIST’s on-wrist health and environmental tracking systems.
The primary system we have developed harvests energy from swinging motions, such as that generated by the arm of a person walking. The system utilizes an arrangement of piezoelectric beams that are “plucked” by posts on an eccentric rotating mass. This strains the beams, generating a current.