Two-Direction MEMS Impact Acceleration Switch

This article summarizes research on a novel, two-direction impact acceleration switch. To sense the change of two direction impact acceleration, A MEMS impact acceleration switch with two sensitive directions was designed. In this design, four serpentine springs were used to fix and suspend the movable electrode (sensing mass). The motion of the sensing mass was investigated by theoretical analysis and finite element analysis (FEA). To investigate whether the serpentine springs´ intensity was enough, the switch of the 1500g threshold acceleration in y direction and the 800g threshold acceleration in x direction was designed, simulated with Covent or Ware respectively. The simulation showed that the threshold accelerations basically fulfill the expectancy. To ensure the unintentional vibration inputs would not drive the sensor mass to the fixed electrode, the mode of the switch was analyzed and its natural frequency and the corresponding mode shapes were obtained from the calculation.