A Combined MEMS Threshold Pressure Sensor and Switch

In this study, a combined threshold pressure sensor and switch is introduced. The sensor detects when the pressure drops below a threshold value and automatically triggers a switch without the need for any computational overhead to read the pressure or trigger the switch. This system exploits the significant fluid interaction of a MEMS beam undergoing a large oscillation from electrostatic levitation to detect changes in ambient pressure. The levitation electrode configuration is combined with a parallel-plate system by adding an extra voltage to an electrode that is traditionally grounded, giving the system the ability to simultaneously act as a switch by toggling to and from the pulled-in position. It is experimentally demonstrated that the pressure sensing/switching mechanism is feasible and the threshold pressure to trigger the switch can be controlled by adjusting the voltage applied to the switch electrode.