A Non-resonant Frequency Up-converted Electromagnetic Energy Harvester from Human-body-induced Vibration for Hand-held Smart System Applications

We present a non-resonant, frequency up-converted electromagnetic energy harvester that generates significant power from human-body-induced vibration, e.g., hand-shaking. Upon excitation, a freely movable non-magnetic ball within a cylinder periodically hits two magnets suspended on two helical compression springs located at either ends of the cylinder, allowing those to vibrate with higher frequencies. The device parameters have been designed based on the characteristics of human hand-shaking vibration. A prototype has been developed and tested both by vibration exciter (for non-resonance test) and by manual hand-shaking. The fabricated device generated 110 μW average power with 15.4 μW cm⁻³ average power density, while the energy harvester was mounted on a smart phone and was hand-shaken, indicating its ability in powering portable hand-held smart devices from low frequency (<5 Hz) vibrations.

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