A miniaturized toroidal piezoelectric device for monitoring human movement and powering wearable electronics

Abstract

Wearable micro-energy devices offer the exciting potential to serve as self-powered monitors for human motion and as power sources for wearable electronics. However, challenges persist, particularly in low-frequency energy conversion and multi-dimensional motion monitoring. In this paper, we report a highly stable and durable miniaturized toroidal piezoelectric device (MTPD) to detect and recognize human movement with exceptional sensitivity, while also storing the generated electrical energy in capacitors to power wearable electronics. The system features a PVDF film that oscillates between ring brackets in a contactless manner, enabling it to capture multi-directional body motion and convert it into electrical signals. By incorporating multiple magnets, the system enhances the deformation of the piezoelectric thin film, thereby improving the output voltage. Furthermore, the integration of multi-channel signal fusion within a compact space refines the accuracy of motion recognition algorithms. We have validated the MTPD’s capability to identify arm and leg movements, highlighting its potential for use in human motion detection. Additionally, we demonstrated the system viability to serve as a power source by efficient charging a capacitor within a short period.