Vibration energy harvesting for wireless underground sensor networks

Recent developments in wireless underground communication have enabled the realization of underground sensor network applications. To this end, it is desirable to provide a sustainable operation for wireless underground sensor networks (WUSNs) with extended lifetimes as maintenance is significantly costly. One promising method towards sustainable operation is to harvest energy underground based on the vibration sources in the environment. However, to the best of our knowledge, underground vibration energy harvesting has not been investigated before. In this paper, the feasibility of vibration energy harvesting for WUSNs is investigated. First, an analytical framework is developed to model the maximum harvestable power by a piezoelectric energy harvester at a certain depth underground, due to an above-ground vibration source. Then, field experiments are conducted to measure the vibration in an agricultural testbed and evaluated the harvestable output power. The results from this study illustrate the feasibility of vibration energy harvesting as a promising approach to be considered for the future underground sensor networks.