FPGA controlled MEMS inclinometer

A FPGA (Field Programmable Gate Array) controlled inclinometer based on MEMS structures is presented in this paper. Pull-in voltage measurements are used in this work as the transduction mechanism. The pull-in phenomenon is characterized by the sudden loss of stability in electrostatically actuated parallel-plate actuators and since pull-in voltage is stable and easy to measure, it enables an interesting transduction mechanism. By successively bringing the microstructure to pullin while measuring the pull-in voltage allows the detection of external accelerations. A FPGA is responsible to control the entire system increasing its performance and reliability. The sensor resolution is defined by the resolution of the measured pull-in, i.e., resolution of the actuation voltage. Experimental results show a sensitivity of 50 mV/^o with the resolution of the actuation voltage set below 1 μV using a 24-bit Digital-to-Analog Converter (DAC).