Development of a meso-scale dual-axis steel accelerometer with hall-effect sensors

We present here an overview of the work done on the development of a meso-scale dual-axis spring steel in-plane accelerometer equipped with Hall-effect sensors. The design of the accelerometer has the unique feature that there is perfect de-coupling of the motions in the two in-plane orthogonal directions. One more extra feature is the use of rechargeable Li-ion batteries as a part of the proof-mass in addition to serving as the power source. The mechanical element of the accelerometer is made of EN J42/AISI 1080 spring steel foil machined using Wire-cut Electro-Discharge Machining (EDM) process. Allegro A1395 linear Hall-effect sensors are used to transduce the displacement of the proof-mass into voltage. The packaged sensor has an overall dimension of 73 mm × 73 mm × 28.5 mm. The packaged sensor can detect an acceleration signal as small as 25 milli-g with a measured sensitivity of 78 mV/g and 102 mV/g along X and Y axes respectively. Reason for asymmetry and scope for improvement in performance, reduction in size, and batch production are also discussed in this paper.