Toward an Autonomous Sensor Node Exploiting a Nonlinear Energy Harvester

This article addresses the characterization of a nonlinear energy harvester (NLEH) underpinned by a snap-through buckling mechanism that operates as a bistable system. With the underlying ansatz that the NLEH can be operated to power up sensors, the NLEH behavior when subject to a sinusoidal deterministic signal with a superimposed noise floor has been investigated. To precisely quantify the NLEH response, a technique to measure the input mechanical power (by quantifying the beam acceleration) has been developed; this leads to a measurement of its efficiency. The best case shows an efficiency value of 3.52% @ 7.0 Hz. Further, the ability of the NLEH to power an external sensor board and transmit data wirelessly to a remote base station has been investigated. This quantification is supported by a measurement of the 'cold start time' and an analysis of the mean activation time for successive activations as a function of the deterministic input and noise intensity. As an example, a cold start time of 15.85 s and a successive activation time of 5.88 s have been observed in the case of a deterministic input @ 9.0 Hz.