Fully enclosed bearing-structured self-powered rotation sensor based on electrification at rolling interfaces for multi-tasking motion measurement

A fully enclosed bearing-structured self-powered rotation sensor (SPRS) is developed for multi-tasking motion measurement. Due to contact electrification between fine-sized rolling beads and a pair of planar electrodes, the SPRS produce cycled electric signals when attached to a revolving axis. They are then analyzed to reveal the rotation rate of the axis and other corresponding derivable parameters, including speed, acceleration, and traveling distance. The device displays high precision, broad range, quick response, and excellent durability. It has novel dual roles as a rotation sensor and a structural ball bearing, making it easily applicable to a variety of circumstances. Integrated with a signal-processing interface, the compact-sized and light weighted SPRS was practically demonstrated in providing real-time motion monitoring for a vehicle wheel. It is promised to be used in a wide range of areas, including transportation, automation, consumer products, and industrial monitoring.