Multiple nonlinear oscillators for autonomous Wireless Sensor Nodes

In this paper, we present an array of coupled nonlinear oscillators suitable to be applied in Wireless Sensor Nodes and autonomous devices. The energy to be harvested comes from ambient vibrations as external energy sources. In particular, we consider two sources increasingly available in the ambient or in the human body and often both are mixed together: periodic induced waveforms and stochastic sources. The oscillator is composed of multiple magnetically-coupled bi-stable cantilevers with different natural frequencies inside each single well. The structure of the oscillator, modeling, simulations and measurement data will be here described. The principle has been validated and compared with other nonlinear techniques already proposed in literature. In particular the results show the possibility to efficiently recovery energy from mixed-sources having rich spectrum dictated by random vibrations and low frequency peaks consequence of periodic sources. The proposed device, based on piezoelectric output, is suitable to be used as converter in order to supply wireless sensor networks, autonomous nodes or it can be applied as power sustainer for communication of integrated devices and contactless measurement systems.