Itchy: step size solution

The engineer who came pre-installed at our workshop pointed out to me the way to do steppers.

The Arduino can tick over far faster than the stepper driver wants to move. (This may not in fact be true; I went for some rather over-spec stepper drivers. But arguendo, this is the case.) So, I use the smallest size of step, and crank up the tick rate. I can use the Arduino to time the steps so if I want to slow down, I’m just missing out a lot. That restores a lot of the pins I thought I was going to need, and makes me a happy person.

He also had some things to say about end stops and soft stops – he says it’s best to do it in the microcontroller, because that will keep track of the last direction in which you moved. If you try to cut out the stepper controller by over-riding the direction at the same time, you’re going to get a race condition.

Lastly he added the purely mechanical point that you can ramp the head up the cut-out switch rather than risking flattening it coming in from on top, and still have the hard stop beyond the switch so nothing falls off at high speed.

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