Self‐Powered Smart Proximity‐Detection System Based on a Hybrid Magneto‐Mechano‐Electric Generator

Abstract

A hybrid magneto‐mechano‐electric (H‐MME) generator that combines a Mn‐doped Pb(Mg1/3Nb2/3)O3‐Pb(Zr,Ti)O3 piezoelectric single crystal and an electromagnetic induction coil is demonstrated to convert stray magnetic noise of 60 Hz into useful electrical energy. The authors optimize the design of the piezoelectric cantilever, the weight of the magnetic mass, and the distance between the magnet and coil through theoretical simulation and experiments to maximize each contribution for the H‐MME generator. The total root mean square output power of the H‐MME generator is 28.35 mW with a power density of 0.042 mW cm−3 Oe2 in a 5 Oe magnetic field of 60 Hz, which is sufficient for driving multiple functional Internet of Things sensors that detect temperature, humidity, light, UV radiation, air pressure, and sound. In addition, a self‐powered smart proximity‐detection system (including a microcontroller unit, an ultrasonic sensor module, a piezo speaker, and a Bluetooth module) is demonstrated by rectifying the output of the H‐MME generator and controlling it using a power management circuit. The superior output power of the H‐MME generator exceeds simple sensing functions and presents the possibility of achieving battery‐free self‐powered smart devices and systems.