Arduino Motor Shield REV3 [A000079] - Motor Control, 4 DC Motors, 2 Stepper Motors, 1.2A per Motor, Integrated Power Supply, Compatible with Arduino IDE for Robotics and Automation Projects

I repost this comment in a thread like this every few months. :) I did a project like this for Little Shop a little while ago. It was very much on the edge of my knowledge at the time, and there's a lot of things that I'd do differently/better now, but just to share what I wound up with: I bought a cheap clock movement on amazon (https://www.amazon.com/dp/B08BHVMF2K?th=1). I also bought a NEMA 17 stepper motor (https://www.amazon.com/dp/B0B38GX54H) and motor driver (I actually bought a motor shield specifically for arduino, I'm sure there's a cheaper option but this was really easy: (https://www.amazon.com/dp/B0084ZQF3O)) and I had an arudino hanging around from a different project. I took apart the clock movement and decided to just drive it by jamming a shaft from the stepper into the middle of one of the gears, which would drive the rest of the movement to turn the hands in the proper ratio. It was crude but it worked. I 3D printed a new back for the movement that included a mount for the motor and a hole for the shaft, and I printed an adapter from the motor shaft to a small bit that could stick inside the movement gear. And then I superglued it and hoped. :) Somehow it survived two weekends of shows. I'm better at 3D printing stuff now and would be able to make something more elegant but this got the job done. I used a stepper motor library for arduino and set it up so that it would advance the clock to a certain time every time a button was pressed. Given more time on the project I probably would have set it up to also have the clock running at normal speed, but this all came together at the last minute so I was really just hoping that the superglue would hold and that the sound of the motor wouldn't be ridiculous (it was covered by transition music so it turned out fine, but it was louder than I would have liked. Like I said, I was learning all this as I went so I think in retrospect a servo might have been a better option.) My suggestion is to just buy one or two of those cheap movements and take one apart and you'll likely see a pretty straightforward way to drive the gear train directly with your motor, especially if you've got a 3D printer and some ability to draw objects to print. Here's a model of the monstrosity I wound up making: https://imgur.com/a/Gna5pKZ I uploaded the 3D models (STL and Step) and the Arduino sketch just in case it helps you at all, it's definitely not a nice, packaged project or anything but it might give you ideas or threads to pull on: https://gist.github.com/kevinrmccoy/e74f07c1692df987d75851a2efd2a65d https://www.printables.com/model/1551339-bracket-for-stepper-motor-and-clock-movement