Quote Originally Posted by David Buchhauser View Post
John - I'm surprised that there isn't already someone out there who has done a similar clock winding project and documented it. I have not heard of a 1-way bearing before - I will need to look that one up. Did you purchase the arduino board and stepper motor as a kit? The stepper motor drives I have used in the past always had settings (jumpers or switches) to match the drive current to the particular stepper motor rated current. Perhaps you could measure the torque required to wind your clock and make sure that your particular stepper motor has the ability to supply that torque in a reliable manner.

I found one guy who has a stepper motor driving a marble lifting mechanism in his clock, but he didn't volunteer much when I contacted him. Others are using a DC motor, like the one I have in the clock now. One-way bearings are fairly common; all kinds of them on Amazon. I bought the Arduino, stepper motor and A4988 driver separately. There is a potentiometer on the driver that you adjust so the current matches the motor rating. The torque requirement to raise the weight on the clock is 0.7 lb-in and the stepper is rated at 2.3 lb-in holding torque, so it should work. I set the potentiometer based on a calculation using the motor winding resistance, but maybe I should have measured the current directly to confirm. I'll have to look into it before throwing it in a drawer and buying a more powerful one.