A tunable-resonance faraday device for dual cardiac sensing and energy harvesting

Efficient energy harvesting from the mechanical energy of cardiac motion is an attractive means to avoid the use of batteries in implantable sensors for non-life sustaining applications. Ideally, a single device would integrate both sensing and energy harvesting functionality. This work describes a novel electromagnetic system that achieves high sensitivity sensing of cardiac signals while simultaneously providing adaptive and efficient energy harvesting capability utilizing tunable resonance. The harvested mechanical energy can then be deployed for myriad purposes including self-sustaining sensor operation, trickle charging of other nearby battery-powered devices (e.g. pacemakers), data logging, or periodic telemetry. Although some harvested energy is required adaptively tune a mechanical resonant frequency, this energy expenditure occurs at a relatively low frequency and is minimized with the chosen design concept. A prototype design is constructed and tested to demonstrate the viability of the approach.