The Geneva mechanism was used in film projectors to advance film one frame at a time in the path of a projection beam. At projection speed, the mechanical sound of this gear is responsible for the clackety noise associated with projectors.
This is a 3D animation model of the Geneva mechanism built and animated in blender. I thought it would be entertaining to have 3 of them arranged around the drive wheel to form a kind of fidget spinner.
![](https://i.ytimg.com/vi/iuVvreh2LeE/maxresdefault.jpg)