Ooops, it’s been a while since I was last active here, sorry about that.
But to offer someting in retribution, here’s a device that can count revolutions or any other event that closes a switch, and tell you how many times that happens in a minute.
I have a need for this device, because I am building a dolly for timelapse images. The dolly has a 2m long worm screw that makes the dolly travel along an axis. If the trip takes, say, 3 hours, and the dolly carries a camera that is set to take an image every 5 seconds, we get a 3 x 60 x 20 image timelapse, ie. 4,800 images. With 25 images per second in a video, that gives you a 192 seconds, or, a little over 3 minute time lapse. During which the camera moves, you see, it’s not just a timelapse.