The esp32s cams are kind of amazing and very very cheap. They have a few quirks, but once you get them going it’s easy to do a bit of a machine vision with them. In my case, new to this kind of thing, I used previous work by Richard to find the weight of change between two consecutive images. Dirk has since made better versions using a PID library. I made some felt-faced ones using meccano and then some lego ones using some nice lego-compatible servos from Pimoroni. Because esp32s can run their own webserver you can use websockets or mjpeg to debug them and see what they are doing.