Tipping-bucket self-powered rain gauge based on triboelectric nanogenerators for rainfall measurement

The traditional tipping-bucket rain gauge (TBR) has the problems of low measurement accuracy and severe abrasion under heavy rainfall conditions, and cannot realize the real-time rainfall monitoring and rain energy harvesting. In this work, a TBR based on manifold triboelectric nanogenerator (TENG) units is proposed to solve the above problems. The significant parameters affecting the electrical output performances of freestanding TENG (F-TENG) and contact-separation mode TENG (CS-TENG) units are comprehensively explored and then optimized from the theoretical and experimental perspectives. Based on the optimized structure of TENG units, a series of experiments for sensing and power generation performances and demonstrations of the TENGs-based TBR are carried out. The experimental results indicate that the proposed TBR can detect the real-time and average rainfall intensities ranging from 0 to 288 mm/d with a minimum rainfall amount resolution of 5.5 µm. Besides, the frequency of the output electrical signal varies linearly with the rainfall intensity but invariant as the humidity changes. More importantly, the rain gauge can obtain the peak output power of 7.63 mW by the CS-TENG unit with a multilayered structure at 250 mm/d. Therefore, the proposed TENGs-based TBR as a rainfall sensor has real-time measurement ability, high resolution, excellent anti-humidity interference ability, as well as rainwater energy harvesting function. The presented multi-functional TBR has great potential to achieve monitoring and data delivery of rainfall information in extreme environments, contributing to the further development of self-powered wireless sensor networks of rainfall information. A novel tipping-bucket rain gauge (TBR) integrated with triboelectric nanogenerators (TENGs) is proposed, which can realize real-time rainfall sensing by a freestanding TENG (F-TENG) and rainwater energy harvesting by a contact-separation mode TENG (CS-TENG). Moreover, it has excellent anti-humidity interference ability and high resolution using a novel approach of sensing index with output frequency of the F-TENG. This work has great potential to achieve monitoring and data delivery of rainfall information in extreme environments, contributing to the further development of self-powered wireless sensor networks of rainfall information. • A TENGs-based TBR for real-time rainfall sensing and energy harvesting is proposed. • Sensing index with frequency of a F-TENG realizes anti-humidity interference ability. • The raindrops are collected by TBR for a CS-TENG to capture more electrical energy.