A Facilely‐Fabricated Electret‐based Flexible Vibration Sensor Featuring A Multifunctional PDMS Seismic Mass for Enhanced Sensitivity and Durability

Abstract Electrets can be used to develop self‐powered vibration sensors that rely on charged dielectrics to measure vibration parameters. A critical challenge in the sensor design is to simultaneously enlarge vibration amplitude and maintain a high surface voltage of the electret. In this study, an electret‐based flexible vibration sensor (E‐FVS) featuring a multifunctional PDMS seismic mass (MPSM) is proposed. Fabricated via molding, the MPSM comprises three parts: 1) a protruded additional mass for increasing the resonance vibration amplitude to enhance peak sensitivity, 2) a perforated film that reduces air damping to improve the overall sensitivity, and 3) a micro‐protrusion stopper that improves the durability by suppressing contact discharge in case of exposure to unexpectedly large accelerations. The E‐FVS operates effectively with excellent sensitivity (up to 1.154 V·g −1 ) in a frequency range of 15–600 Hz and good linearity ( R 2 > 0.99) within an acceleration range of 0–5 g . Remarkably, the output voltage of the sensor has only attenuated by 0.75% after one million vibration tests. Combined with deep learning, the E‐FVS achieves a 99.17% accuracy in state identification of a self‐made fan. Monitoring of other vibrating machinery and human motion is also demonstrated, showing the sensor's broad application scenario.