A hybrid self-powered wave sensing device enables low-amplitude wave sensing

<h2>Summary</h2> Ocean spectra are used to predict the distribution of wave energy, which is key to harvesting ocean wave resources, such as tidal and wave energy, in order to obtain renewable electricity. Current radar-technology-based wave sensors struggle with monitoring low-amplitude waves in shallow water due to the sensors' bulky size. A hybrid self-powered wave sensor (HSP-WS) consisting of an electromagnetic generator (EMG) and a triboelectric nanogenerator (TENG) is proposed in this study. The EMG, in cooperation with the power management system, demonstrates the ability to power Bluetooth devices to enable remote signal transmission or can be directly used as a flashing indicator. The TENG shows a linear relationship between the strength of the output signal and the wave amplitude. Both the EMG and TENG demonstrate durability for use as a device for low-amplitude wave spectrum measurement. HSP-WS provides the feasibility to fill the gap in the low-amplitude wave spectrum, leading to better utilization in ocean wave resources.