Achieving Dual‐Function In Situ Monitoring of Water Level and Flow Velocity via a Flapping‐Wing Triboelectric Nanogenerator

Abstract Real‐time monitoring of water level and flow velocity is essential for reflecting hydrodynamic properties, serving as a core component of intelligent hydrological monitoring systems. However, the measurement accuracy and anti‐interference capabilities of existing sensing methods limit their practical applications. Here, a flapping‐wing water level‐velocity method (FWVM)is proposed, which combines the flapping‐wing motion with the triboelectric nanogenerator (TENG). Through the decoupling analysis of the TENG characteristic signal reflected by the flapping wing motion, the information of water level and flow velocity is extracted. Based on this method, a self‐sustaining flapping wing TENG (FW‐TENG) with a water level resolution of 1 mm is established. The accuracy and stability of FW‐TENG are improved through optimization of the wing shape and the magnetic drive design. Furthermore, a dual‐function monitoring system has been developed for real‐time in situ monitoring and early warning of water level and flow velocity. Compared with a commercial sensor, the error rates of maximum water level and flow velocity are below 0.45% and 2%, respectively. This research provides an approach for the development of underwater sensors and holds great potential for widespread application in hydrological monitoring.