EcoMicro

Abstract

This paper describes EcoMicro, a miniature, self-powered, wireless inertial-sensing node in the volume of 8 x 13 x 9.5 mm3, including energy storage and solar cells. It is smaller than existing systems with similar functionality while retaining rich functionality and efficiency. It is capable of measuring motion using a inertial measurement unit (IMU) and communication over Bluetooth Low Energy (BLE) protocol. It is self-powered by miniature solar cells and can perform maximum power point tracking (MPPT). Its integrated energy-storage device combines the longevity and power density of supercapacitors with the relatively flat discharge curve of batteries. Our power-ground gating circuit minimizes leakage current during sleep mode and is used in conjunction with the real-time-clock for duty cycling. Experimental results show EcoMicro to be operational and efficient for a class of wireless sensing applications.