15 th National Conference on Machines and Mechanisms NaCoMM2011-141 Development of a Meso-scale Dual-axis Steel Accelerometer with Hall-effect Sensors Sambuddha Khan, P. Muddukrishna and G. K. Ananthasuresh Abstract 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. Keywords: Accelerometer, meso-scale, dual-axis, Hall-effect sensor, mechanism and Wire-cut EDM 1 Introduction Accelerometers are one of the most widely used sensors today because of their importance in many devices and the availability of different manufacturing technologies and batch-fabrication processes. Miniaturized sensors are becoming popular because of their low cost and uncompromised performance as compared to their macro counterparts. Silicon micromachining is one of the most widely used manufacturing technologies that enable miniaturization of sensors such as accelerometers, gyroscopes, etc. without compromising their performance. Many applications that use micromachined accelerometers require low to medium resolution of the order of milli-g / Hz (milli-g means one thousandth of the acceleration due to gravity, i.e., -3 2 10 × 9.81 m s ) or better resolution. Commercially available micro-machined milli-g accelerometers are inexpensive but the micro-g accelerometers are very expensive as they require both sophisticated and expensive fabrication technology and transduction techniques. (e.g., tunnelling current-based [1]-[3] and laser interferometry based [4, 5]) that are not suitable for ________________ Sambuddha Khan Multi-disciplinary and Multi-scale Device and Design (M2D2) Laboratory, Department of Mechanical Engineering, Indian Institute of Science, Bangalore-560012, E-mail: sambud@mecheng.iisc.ernet.in. P. Muddukrishna Multi-disciplinary and Multi-scale Device and Design (M2D2) Laboratory, Department of Mechanical Engineering, Indian Institute of Science, Bangalore-560012,E-mail: krishepm@mecheng.iisc.ernet.in. G. K. Ananthasuresh Multi-disciplinary and Multi-scale Device and Design (M2D2) Laboratory, Department of Mechanical Engineering, Indian Institute of Science, Bangalore-560012, E-mail: suresh@mecheng.iisc.ernet.in. 1