A self-powered wireless sensing node for event-driven alerting based on a bi-stable vibration energy harvester

This paper reports a fully self-powered wireless node for sensor-network that monitors the kinetic amount of mechanical vibration. The self powered sensing function is enabled by a newly developed energy-harvester that can generate considerable electric power only when the monitored amplitude of the vibratory acceleration reaches or exceeds a pre-set threshold. The generated electric-energy can be accumulated over time into stored charge to represent the converted kinetic-energy amount of the concerned vibration. The vibration event induced electric energy can drive an RF transmitter to send out alerting signal. Without traditional sensor used, the wireless signal already includes the sensing information. The vibration-threshold triggered generation function can avoid false-alarm caused by ambient vibratory noise.