Suggestions for a small and accurate stepper motor

Other Hardware Motors, Mechanics, Power and CNC
1

So I'm making a clock with a stepper motor.
I know that I could get a clock movement, but I want to integrate other features like timers and alarms into it, and the only way I can think of doing this is by using a stepper motor to control the time.

In my first prototype I have used a basic 28-byj48 stepper motor which I modded to bipolar because my ULN3003 driver stopped working (Ardufocus | 28BYJ-48 Bipolar Mod) - I'm also wondering if this mod could potentially reduce the accuracy of the motor as well.

However, I am trying to find a better stepper motor, with the main aim of it being as accurate as possible, within reason, i.e. I don't really want to be spending much more than $20USD per motor. It can also be very weak as all it has to do is move a light plastic hand.

Any suggestions would be greatly appreciated, thanks.

2

You might consider using the same motor again, but adding a sensor to know when you have a full turn on the clock hand. This way, no error will accumulate, and when there is an error, it will be cleared on each turn.

3

Hello sw369

Did you consider to use a servo instead?

4

Thanks for the suggestion. The only problem is that the stepper I have is actually quite accurate in getting to the same spot after a full revolution. The main problem is slight differences throughout the revolution. Too be honest, all functions can be done with the current motor, its just I was wondering if anyone could suggest a better more accurate solution to make it a bit nicer really.

5

Actually that never even crossed my mind. But now thinking of it, with some gearing, that definitely could work, and would probably be more accurate.

The only thing is that say every 12 hours, it would have to move anticlockwise from 11:59 back to 0:00.

6

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