জাইরোস্কোপ

And here are some incredible things you can do with a gyroscope:

This is a very useful technique for navigation and if you want to see how these sensors work then you can have a visit on https://babasupport.org/apple/iphone-error-4005/ where you can learn about the components.

Gyroscopes are intricate objects whose equations of motion are hard to solve analytically, yet demonstrates many interesting properties such as precession.

This video by Veritasium explains it very well: https://www.youtube.com/watch?v=ty9QSiVC2g0