Ambient energy harvester design for a wireless sensor network

The self-powered wireless sensor network (WSN) is an appealing approach for structural health monitoring applications. We present a solar energy harvesting hardware to store energy in supercapacitors that supply power to the wireless sensor nodes in a WSN based bridge monitoring system. A control circuit with the ultra-low power consumption components is designed to prevent further energy loss when the voltage dropped below a given cutoff voltage and to make sure the super capacitor charging circuit works close to the maximum power point of a solar panel and to the operating voltage of wireless sensor node. Design goals of the energy harvesting and storage circuit include low-cost, low-power consumption, and a simple design. The performance of the proposed circuit has been evaluated on the basis of the simulation and data logging through the deployed self-powered system prototype on the bridge. Results show that the designed harvesting hardware can achieve self-sustainability during the fluctuating light conditions and able to swift back to operation above cutoff voltage.