Peripheral acceleration sensor

Operation principle of the peripheral acceleration sensor

The centerpiece of the sensor is a micromechanical sensor element comprising fixed and moving finger structures and spring pins. A special process is used to incorporate the spring/mass system on the surface of the silicon wafer. The seismic mass with its comb-like electrodes is resiliently suspended in the metering cell. A linear acceleration in the sensing direction changes distance between the moving and fixed structures, which also alters the capacity. This in turn results in a change of the electronic signal, which is amplified and filtered by the electronic evaluation system and then digitized so that it can be transmitted to the airbag control unit.