Self-powered triboelectric velocity sensor for dual-mode sensing of rectified linear and rotary motions

A practical self-powered velocity sensor based on the principles of a triboelectric generator for either rectified linear or rotary motion is presented. The effort represents the first successful attempt in integrating a triboelectric generator into a commercial digital circuit for the dual-mode speed sensing. Employing alternating Kapton-copper strips arranged in a spiral configuration wrapped on the inner and outer surfaces of two concentric cylinders, voltage assays for linear and rotary motions can be measured without the need for an external power source. The triboelectric generated output signals when integrated with a digital circuit and a microcontroller unit can be directly processed into remarkably stable, macro-scale output signals for measurements of (0.1-0.6)ms^-1±0.5% for linear velocities and (300-700)rpm±0.9% for rotary velocities. We have also discussed the measuring sensitivities and limitations of our device in the paper. We believe our pioneering demonstration of the applied triboelectric technology will have a huge impact in the industrial commercialization of self-powered devices and sensors.