A Hybrid Vibration Powered Microelectromechanical Strain Gauge

This paper reports the demonstration of an ultra-low-power micro-electromechanical system (MEMS)-CMOS oscillator for strain sensing, powered by a miniature piezoelectric vibration energy harvester (VEH). The employment of the Pierce oscillator topology in a MEMS-CMOS oscillator allows for the minimization of the power requirement to as low as $1.1~\mu \text{W}$ under ideal conditions. A VEH prototype, developed with hard lead zirconate titanate on a stainless steel substrate ($\sim 0.4$ -cm
³
practical operational volume), is able to deliver a typical average power of $187~\mu \text{W}$ at 11.4 ms$^{-2}$ and 514 Hz. Some of the practical challenges associated with the integration of the harvester and the MEMS sensor have also been explored, which helps to lay the foundation for realizing net-zero-power strain sensors.