Sensors and actuators a-physical vol:37-8 pages:86-90
For the in vivo measurement of the state of motion of animals, a subminiature capacitive movement detector with dedicated analogue interface circuit and digital postprocessing is developed. A switched capacitor circuit converts the variable capacitance of the movement detector into a voltage, linearly dependent on the acceleration. Postprocessing is necessary to obtain an efficient telemetry system in terms of power consumption and transmission time. The micromachined movement detector has an overall size of 1 mm3. Design concept and fabrication procedure are elaborated with emphasis on the most critical stages.