I don't think it is related to switching of the stepper.  The motor moves
smoothly through individual movement segments.  The issue is how to match
the filtering of an input to the rapid motion of a needle.  With a digital
display, we simply do not notice the jerky nature of a filter function as it
homes in on a value.  The needle does, though.  So the question is one of
filtering such that it is smooth, and yet not so slow that it is not, well,
slow.

I see great ideas so far, and am about to try Tom's ideas.

Thans
Chris Eddy

Russel said:

>Then, if you are using a stepper motor,  there is microstepping - instead
>of just applying steps you PWM between adjacent steps and vary the PWM
>ratio smoothly.
>
>This can work very nicely.