Gyroscope

A gyroscope is a device used for measuring or maintaining orientation and angular velocity, built around a spinning wheel or disc whose axis of rotation is free to assume any orientation and, by conservation of angular momentum, resists tilting or rotation of its mounting. The German astronomer Johann Bohnenberger built an early instrument version in 1817, and the French physicist Leon Foucault named and popularized the device in 1852 while using it to demonstrate the Earth's rotation. Gyroscopes built on the same spinning-mass principle, and later on microchip MEMS and other operating principles, became central to inertial navigation, spacecraft attitude control and aircraft instruments, and now appear in everyday consumer electronics such as smartphones and game controllers.