An accelerometer is a sensor that measures proper acceleration (the acceleration it experiences relative to freefall). It is widely used in electronics, vehicles, robotics, and industrial systems to detect motion, tilt, vibration, and shock.
How an Accelerometer Works
- Most modern accelerometers are MEMS-based (Micro-Electro-Mechanical Systems) and measure acceleration using tiny capacitive, piezoelectric, or thermal mechanisms.
- They detect static acceleration (like gravity for tilt sensing) and dynamic acceleration (like vibrations or movement).
- Typically measure acceleration along 3 axes (X, Y, Z).
Key Applications
- Smartphones & Tablets – Screen rotation, step counting, gaming controls.
- Automotive – Airbag deployment, electronic stability control (ESC).
- Drones & UAVs – Flight stabilization.
- Industrial Machines – Vibration monitoring for predictive maintenance.
- Wearables – Fitness tracking (step counting, activity recognition).
- Robotics – Balance and motion control.
Types of Accelerometers
- Capacitive MEMS – Most common (used in phones, IoT devices).
- Piezoelectric – Used for high-frequency vibrations (industrial sensors).
- Piezoresistive – High-impact sensing (e.g., automotive crash detection).
- Thermal (Convective) – Used in some low-cost applications.
Output Data
- Measured in g-force (9.81 m/s² = 1g) or m/s².
- Example:
- 0g on X, 0g on Y, 1g on Z → Device is flat on a table.
- -1g on Z → Device is upside down.
- Sudden spike in acceleration → Possible impact or shake.
Common Accelerometer ICs
- ADXL345 (Analog Devices) – Digital 3-axis, used in many embedded systems.
- MPU-6050 (InvenSense) – Combines accelerometer + gyroscope.
- LSM6DS3 (STMicroelectronics) – Popular in wearables and phones.
- BMA250 (Bosch) – Low-power accelerometer for IoT.
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