I see now, I only read the title, and didn't look at the picture.

Here's an example of what I was talking about. This is what came up in a search result, so I don't know if it's high quality, or crap.

There are various sizes of these motors, and they have knobs to determine how far they should turn each direction.

https://lightdepsolutions.com/product/light-deprivation-motor/