Precision of rotation

Third part of building a digital clock with analog displays

I spent some time today trying to figure out whether the precision of rotation directly from my motor is good enough for my clock. Steppers motors can lose steps if the load is too much for it, even though in my case it's plenty of torque. In the final clock, I would have to rotate the dials once every 12 hours at the slowest, and 30 degrees every hour. And I will be turning the motor off when I am not rotating it, as in no current will flow through the coils. This is to conserve energy and not to make the motor hot. Steppers tend to get quite hot when they are idling if I remember from my college days.

So I wrote some code & stuck a piece of paper to verify if stepper is losing steps for one single rotation.

Ran it for half an hour or so, with plenty of full-rotations. This is fine! Even if it loses steps later, I will have hall effect sensors in place to re-sync the rotation offsets if I need to. Plenty of accuracy for a wall-clock.

Then I trieid splitting the rotation into 16 pieces, i.e. for this motor, 128 out of 2048 steps. Seems to be working really nicely.

23-12-2024