Cylinder-based hybrid rotary nanogenerator for harvesting rotational energy from axles and self-powered tire pressure monitoring

Tire pressure monitoring plays a pivotal role in vehicle safety system. However, as a conventional battery-operated electronic system, regularly replacing battery remains a great inconvenience in wide-distributed tire pressure sensing. Here, we introduce a self-powered tire pressure monitor by using a rotary cylinder-based hybrid nanogenerator as a sustainable power source. The designed energy harvester, by hybridizing a triboelectric nanogenerator (TENG) and electromagnetic generator (EMG), can scavenge rotational energy from rolling axles. Integrating with transformers, the hybrid nanogenerator can achieve an open-circuit voltage of 16 V and short-circuit current of 0.1 mA at the rotation rate of 150 rpm, respectively, with the maximal output power of about 1.8 mW at the loading of 20 k omega. Via a programmable software, the hybrid device can operate as a self-powered counter and timer for potential speed detecting. Further, it has been demonstrated that the hybrid nanogenerator is capable of triggering a transmitter-integrated tire pressure sensor for self-powered monitoring tire pressure in real time. This study expands applications based on TENGs in automobile engineering, which might promote the development of intelligent driving and traffic safety engineering.