Accelerometer

Measures proper acceleration (g-force) along one or more axes to detect motion, vibration, and orientation.

The accelerometer is an electromechanical sensor that quantifies proper acceleration: the non-gravitational force experienced by an object. Modern units primarily leverage Micro-Electro-Mechanical Systems (MEMS) technology, which etches microscopic structures onto silicon for high precision. This core capability drives critical applications: triggering vehicle airbags, stabilizing flight in drones, and managing screen orientation in consumer electronics (smartphones, tablets). It is also essential for industrial machinery monitoring and high-end inertial navigation systems (INS) for aircraft and missiles.

https://en.wikipedia.org/wiki/Accelerometer