A real-time, self-powered wireless pressure sensing system with efficient coupling energy harvester, sensing, and communication modules

Self-powered wireless sensing systems (SP-WSSs) based on triboelectric nanogenerators (TENGs) are promising in the era of the Internet of Things. However, due to the complex structure, SP-WSSs have high power consumption and cannot work in real time. Here, through efficient coupling among energy harvesting, sensing, and communication modules, the structure of SP-WSS is simplified and the power consumption is reduced for realtime sensing. Firstly, since the sensing and communication are coupled by an LC circuit composed by a handmade capacitive pressure sensor and an inductance coil, the energy for one sensing-communication cycle is reduced to 9 mu J, and the SP-WSS can send a signal every 27 ms at 1 Hz working frequency of TENG. Then, the sensing LC circuit is directly triggered by the TENG using the triboelectric plasma as a switch. Since the ultra-fast switching characteristics of triboelectric plasma (13.2 ns), the communication frequency can reach 72.55 MHz for real-time pressure sensing. And the equivalent impedance of TENG is reduced by triboelectric plasma to achieve impedance matching with the LC circuit, which leads to the energy conversion efficiency of 56% and enables signal transmission distance up to 40 m with a peak-to-peak voltage (Vp-p) of 3 V. These results are new records for SP-WSSs. Finally, a photodetector is incorporated into the circuit, demonstrating the system's capability for collaborative sensing of light intensity and pressure. This work presents a feasible scheme of realtime SP-WSSs, which will greatly promote the practical application of SP-WSSs.