A BI-Directional Low-G MEMS Inertial Switch with Multiple Thresholds for Passive Shock Severity Quantification

In this paper, a passive bi-directional MEMS inertial switch with multiple thresholds is proposed. The switch is successfully fabricated using the SOIMUMPs technology. Its sensitivity in detecting the applied acceleration in the sensitive axis is demonstrated through rigorous testing involving a drop-table test system and subjecting the switch to varying shock accelerations. The switch is equipped with four threshold levels to quantify the acceleration range. The switch consumes virtually zero power when not activated in the passive state. Notably, a low-range shock detection of 46g to 107g is achieved, which is desirable for the head-impact detection application. The switch has a potential for further expansion to include more threshold levels for achieving even greater measurement precision. This development opens up possibilities for low-g acceleration measurements with minimal power consumption, paving the way for many Internet of Things (IoT) applications.