Gyroscope on a Chip

Beyond the accelerometer, your phone has a MEMS gyroscope — another microscopic device. While the accelerometer senses linear motion, the gyroscope detects rotation using the Coriolis effect.

A tiny vibrating mass resists changes in its vibration plane. When you rotate the phone, Coriolis force pushes the mass sideways, and electrodes measure the shift. Combining accelerometer and gyroscope data gives full three-dimensional orientation. This is how VR headsets track your head with millisecond precision and how navigation apps know which direction you are facing even indoors where GPS signals cannot reach.