Self-Powered Droplet Sensor Based on Triboelectric Nanogenerator toward the Internet-of-Things (IoT) Alarm System

Water leakage and condensation induce corrosion of metal components and even short circuits, further leading to emergency equipment shutdowns or safety incidents, posing an arduous challenge to the reliability and stability of modern electrical equipment in moist environments. Herein, we report a self-powered alarm system by integrating a droplet-based triboelectric nanogenerator (DTNG), a microcontroller unit (MCU), a signal processing module, and a wireless transmission module, which can rapidly and sensitively detect and identify water leakage or condensation in the surrounding environment. Among them, the high-sensitivity, low-cost, and durable DTNG can convert the low-frequency disordered kinetic energy of water droplets into concentrated, ordered, and usable electrical energy, enabling the continuous operation of an alarm system. We systematically investigate the impact of hydrophobic modified Poly(tetrafluoroethylene) (PTFE) film thickness, volume of droplet, and tilt angle on the device output characteristics. The optimal DTNG delivers excellent output characteristics (111.6 V, 8.497 μA, and 388.60 μW/m2) and stable cycling performance (95.5% for 28 days). More importantly, we implemented a remote hyetometer and a wireless alarm system for valuable electrical equipment sensitive to water or moist environments, providing novel ideas and unique insights for developing the field of IoT alarm systems and environmental monitoring based on DTNGs.