A self-powered wireless sensing node for ambient vibration pattern identification by using a hybrid energy-harvesting mode

By using a hybrid energy-harvesting mode, a novel self-powered wireless-sensing-node is developed for vibration-type distinguishable environment/event monitoring. The dual-stage piezoelectric vibration energy harvester has threshold-triggered electricity generating function. Such harvesters generate considerable power when the ambient vibration reaches the two preset conditions of acceleration and frequency. According to different output voltage, two such harvesters with different vibration-thresholds can passively distinguish the vibration patterns caused by weak shake or strong knock. Moreover, nonlinear electromagnetic harvesters are also used to generate more electric-power for wireless transmitting the alarm-signals. Both lab test and spot test have verified the vibration-pattern distinguished monitoring and self-powered wireless alarming function.