Impedance Matching Effect between a Triboelectric Nanogenerator and a Piezoresistive Pressure Sensor Induced Self-Powered Weighing

How to develop a simple and stable self-powered force/pressure monitoring system has attracted extensive interests, yet it still faces intractable problems and challenges. As a mechanical force-driven generator, the most straightforward application for triboelectric nanogenerator (TENG)-based sensor is to directly monitor the external pressure. In this work, a self-powered pressure monitor system is proposed by the conjunction of triboelectric and piezoresistive effects, in which a free-standing disk-shaped TENG (FD-TENG) serves as an energy harvester, and a multiwalled carbon nanotube-based flexible piezoresistive pressure sensor (PPS) works as a real-time pressure monitor. The induced output voltage of the FD-TENG is tuned by the working states of the PPS, which is responded to the external weight stimuli. Based on the impedance match between FD-TENG and PPS, the self-powered weighing system renders a voltage varying from 46.2 to 168.6 V in a range from 1 to 20 kg with a fast response/recovery kinetics (1.2 and 2.3 s) and good stability, which enable to directly reflect on the on/off status of appropriate amount LEDs powered by FD-TENG. Finally, it is demonstrated to equip into a successive pedrail transportation system for monitoring the qualified/unqualified weight products.