Energy harvesting from human motion for wearable devices

Energy harvesting technology provides a promising choice to replace the batteries used in modern wearable devices. This paper describes new kind of piezoelectric energy harvesting devices aiming for high power output at low frequency with broad bandwidth. By accessing the performance of the device at different frequencies, we have demonstrated two energy harvesting devices with power output at 10 microwatts level. A complete energy harvesting system is also designed to adjust the output voltage for practical applications. Energy from human motion has been successfully harvested to power an LCD device and an LED lamp. Those demonstrations reveal potential applications of the energy harvester in other wearable devices.