Accelerometers

An accelerometer is a device that measures acceleration, the rate of change of velocity, and typically reports a value corresponding to proper acceleration relative to free fall. It provides a measurable output that is proportional to acceleration along one or more axes. Modern accelerometers are commonly built as microelectromechanical systems (MEMS) and are embedded in a wide range of electronic devices.

Common types include MEMS capacitive accelerometers, piezoelectric accelerometers, and piezoresistive accelerometers. MEMS capacitive sensors use a microfabricated proof mass attached to a spring; acceleration causes displacement that changes capacitance, which is converted to an electrical signal. Piezoelectric accelerometers use piezoelectric crystals to generate charge under stress, making them well suited for dynamic, high-frequency measurements. Piezoresistive devices rely on resistance changes in doped silicon or other materials under strain. Accelerometers can be configured as single-axis, dual-axis, or tri-axis sensors.

Signals are typically amplified and digitized, then transmitted via interfaces such as I2C or SPI, or provided as a digital output. Key performance characteristics include measurement range, sensitivity, bandwidth, noise, temperature dependence, bias drift, and cross-axis sensitivity. MEMS devices are small, low power, and cost-efficient, while high-end piezoelectric sensors may offer greater dynamic range and stability for demanding applications.

Applications span consumer electronics (smartphones, tablets, wearables), automotive safety and control systems (airbags, stability control), robotics and drones, industrial vibration monitoring, and inertial navigation when combined with gyroscopes in inertial measurement units (IMUs). Calibration and temperature compensation are important for maintaining accuracy over time.