A 2D omnidirectional inertial switch with multiple thresholds

We introduce a novel 2D omnidirectional inertial switch designed to detect multiple acceleration thresholds that extends the capabilities of existing omnidirectional switches with a single threshold. The device was fabricated using the SOIMUMPs process and enhanced with in-house gold sputtering to increase conductivity. The switch incorporates a suspended proof mass and stationary electrodes to uniformly sense shock-induced displacements from any planar direction. Finite Element Analysis (FEA) was used to optimize the design for uniform stiffness and precise threshold detection across all axial and off-axial planar directions. Testing was conducted using a drop-table system, assessing directional thresholds within the device plane at 15° increments around the full 360°. The results showed average first and second thresholds of 30 ɡ and 100 ɡ, respectively, with maximum variations across the angle increments of 2 ɡ for the first threshold and 5 ɡ for the second threshold. This new inertial switch represents a significant enhancement of omnidirectional sensitivity, making it particularly valuable for triggering applications in essential health and safety monitoring.