Triboelectric nanogenerator-enabled fully self-powered instantaneous wireless sensor systems

The wireless sensor networks (WSNs) play an important and essential role in modern society. However, the requirement for huge distributed energy for sensors and wireless transmission modules has become a bottleneck in the development of WSNs. Various energy harvesting technologies have been explored for developing self-powered sensors, however they either need a long duration for energy collection and storage, leading to not real-time sensing, or require additional power sources to run the WSNs. Here we report a novel triboelectric nanogenerator (TENG)-based fully self-powered instantaneous wireless sensor system. TENG is integrated with an RLC sensing circuit, enabling spontaneous generation of oscillating signal with encoded sensing information. Additionally, by using an electronic switch, the frequency and amplitude of the signal become extremely stable and immune to the environmental variations. An innovative impedance-modulated signal analysis method is also developed to extract the sensing information for resistive, capacitive as well as inductive types of sensors. The sensor system is then applied for real-time tire pressure and speed monitoring for a bicycle. Results showed that the self-powered wireless tire pressure sensor system is able to monitor tire pressure and speed of the bicycle, with a resolution of 5.5 kPa and a precision of about 97% respectively, demonstrating its excellent potential for general applications.