A silicone based piezoelectric and electromagnetic hybrid vibration energy harvester

This paper describes the investigation of a novel low-cost silicone-based hybrid vibration energy harvester (SHVEH) for converting machine vibrations into useful electrical power for wireless sensor nodes. Due to a novel fabrication technique, the harvester has the benefit of incorporating two transduction mechanisms (electromagnetic and piezoelectric) into a single silicone housing for improved output power. In the devised fabrication technique, water-soluble tablets are used to develop a cavity inside the silicone structure for an embedded magnet to vibrate in. The developed device was characterized inside the lab at different acceleration levels. The SHVEH was found to be capable of delivering a combined output power of 1.12 mW and a power density of 52 mu W cm(-3). The SHVEH was able to deliver maximum open circuit voltages of 3 V and 28 mV AC via the piezoelectric and electromagnetic portions, respectively, at a resonant frequency of 110 Hz. Furthermore, after connecting the SHVEH to rectifier circuitry, the DC voltage levels obtained were 3.5 V and 35 mV from the piezoelectric and electromagnetic portions, respectively.