Title

The use of body motion for powering biomedical devices

Document Type

Conference Proceeding

Publication Date

12-1-2009

Abstract

Powering electronic devices from environmental sources such as light and temperature gradients has been demonstrated with commercially viable products such as solarpowered calculators and thermal-powered wristwatches. A new electromagnetic generator approach presented here is found to have the potential to power miniature medical devices. The power output from harvesting environmental energy is proportional to the acceleration-squared-to-frequency (ASTF) and the quality (Q) factor of the system. Human-based activities exhibit large ASTF values and low Q factors while machines are typically associated with low ASTF values and high Q factors. This paper reviews the generation limits of energy harvesting, the possibilities of energy generation from body motion, and the development of a new oscillating generator. The device presented is composed of a rotor with a multipole permanent magnet (PM) ring with an eccentric weight and a stator with a radial gear-shaped planar coil. The oscillations of the rotor due to the eccentric mass when subject to body motion induce a voltage on the planar coil. As much as 2.35μW of power has been produced with a preliminary prototype placed laterally on the hip while walking. It is estimated that energy from human motion could generate as much power as 1mW/cm3with such a device. © 2009 Springer-Verlag.

Publication Title

IFMBE Proceedings

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