Piezoelectric-powered wireless sensor system with regenerative transmit mode

This work shows the first, piezoelectric energy harvester powered wireless sensor system, made using commercial off the shelf components, which is capable of continuous operation at an acceleration of 120 mg (1.17 m/s(2)) at 77 Hz, which is comparable to a small microwave oven. The authors' results show that a highly deployable system can be realised without the need for custom electronics or devices. By using different operating parameters of the onboard peripheral interface controller (PIC) processor and selectively activating components only when they are required, the system awake time can be increased by over 49 times from that of an unoptimised system. This method also allows the onboard storage to recharge during the awake period and, above a certain acceleration, can lead to continuous operation without the need for a charging sleep period. It can also operate at an acceleration of only 40 mg with a system duty cycle of 5%.