A zero-power sensing MEMS shock sensor with a latch-reset mechanism for multi-threshold events monitoring

Abstract

This paper presents the design, modeling, fabrication, and testing of a MEMS passive shock sensor to record multiple threshold events with robust latching mechanism using mass-spring assembly. The latching part on a seismic mass enables the discrete latch positions depending on the applied external impact forces and stores the impact value over a long period of time without any external power supply. A numerical model is developed to understand the dynamic behavior of the device and the proposed shock sensor is capable of sensing a shock range of 20–250 g with 10 threshold levels. The fabricated devices are investigated by applying controllable impact tests, and the experiment results are verified by comparing with the numerical model values. An electrostatic actuator is incorporated for reinitializing the device by releasing coupling between the latching parts for reusability. The shock sensor does not require any power for detection nor storage of acceleration events during its operation. Having high reliability, optimum resolution and reusability makes the device suitable for long-term remote monitoring applications with very limited power supply.