An impact based piezoelectric harvester adapted to low frequency environmental vibrations

Vibration energy harvesters are an attractive option for powering low consumption wireless applications. Piezoelectric inertial devices based on a resonant behaviour are adapted to this type of applications for frequencies of the mechanical input in the range of hundreds of Hertz. However, in the case of human body applications, frequencies of a few Hertz are observed. For this reason, we developed an alternative approach based on the impact of a missile on piezoelectric beams. A model of such a harvester is first presented. Then, a prototype is experimentally characterized: 600 muW were obtained for a 10 Hz frequency and 10 cm amplitude linear motion.