Powering portable electronics using vocal fold vibrations

Using a multi-stacked array of vibration-driven energy harvesters and a custom-tailored energy-harvesting (EH) circuit, we have achieved stable 3.12-mW power generation at 5.5 V
dc
from the acousto-mechanical vibrations of the human vocal folds at 75 dB and demonstrated its use as a practical on-demand power source for portable and wearable electronics. The voltage and power outputs over 3.7 V
dc
and 1 mW necessary for charging lithium polymer (LiPo) batteries were accomplished using a 3D-printed packaging platform whose physical design and mechanical properties maximized the vibration transfer and effectively combined 10 or more individual energy harvesters into a compact unified stack. The custom-designed LC-resonant EH circuit efficiently converted raw AC output into DC. Using our EH device, we have successfully charged 100-mAh LiPo battery and operated a portable 2×16 LCD display (requiring 2.8 V, 10 mA).