sensorsaccelerometers

Accelerometers are sensors that measure acceleration, typically acceleration relative to free fall. In modern devices they are usually micro-electromechanical systems (MEMS) that sense acceleration along one, two, or three orthogonal axes. They convert inertial forces into electrical signals using capacitive, piezoelectric, or piezoresistive principles. Capacitive MEMS accelerometers detect deflection as changes in capacitance between movable proof masses and fixed electrodes, enabling measurement of static and dynamic accelerations. Piezoelectric types respond to stress with generated charge and are generally used for dynamic measurements, while piezoresistive devices detect resistance changes due to strain.

Outputs may be analog voltages or digital values transmitted via interfaces such as I2C or SPI. Specifications typically include sensitivity, bias (zero-g offset), bandwidth, noise density, and dynamic range. Consumer devices often use ±2 g to ±16 g per axis, while industrial and automotive variants extend to higher ranges to tolerate greater shocks.

Most accelerometers are available as single-axis, two-axis, or three-axis sensors. They frequently form the sensing element of inertial measurement units (IMUs), where accelerometers are paired with gyroscopes and sometimes magnetometers to estimate orientation and motion through sensor fusion algorithms. Applications include smartphones and tablets for screen orientation and motion sensing, wearables for activity tracking, automotive safety systems such as airbag deployment and rollover detection, drones and robotics for stabilization, and industrial equipment monitoring.

Calibration and limitations include temperature sensitivity, offset drift, scale-factor errors, and noise. Static measurements require DC-coupled sensors, and performance can be affected by shock, aging, and supply voltage variations.