Accelerometer

This chapter discusses the purpose, principle, specifications, and applications of accelerometer. Accelerometers are widely used as sensors for wearable medical devices to measure and assess physical activity in clinical/laboratory settings or free-living environments. Accelerometers are sensors that are designed to measure the acceleration of an object in motion along reference axes. The most common type of sensors used to measure acceleration are piezoresistive accelerometer, piezoelectric accelerometer, differential capacitive accelerometer, and microelectromechanical sensors-based accelerometer. Three-axis accelerometers can detect motion in three different directions. A typical accelerometer is characterized by several features that include bandwidth, number of axes, and output range. Accelerometers are finding increasing application mostly related to fitness and sports activities. Besides the usual applications involving walking and running, accelerometer-based step counters are promoted to encourage people to walk a few thousand steps each day.