A 19-element Shock Sensor Array for Bi-directional Substrate-plane Sensing Fabricated by Sacrificial Liga

The design, fabrication and testing of a micromachined shock sensor array is described. The sense elements are cantilevers which deflect parallel to the substrate and close a switch when a threshold acceleration is detected. Criteria for their dimensional optimization are presented. The dynamic range for the array is 10 g to 150 g, with a resolution of 10 g. Provisions for electrostatic self-testing are included. With triple redundancy at the 20 g and 100g thresholds, the total area occupied is <21 mm. Measurement results are presented for arrays fabricated by the sacrificial LIGA process. Electrostatic self-testing shows that actuated with a 100V pulse, a dynamic self-test gives a typical closure time of less than 1 ms.