Hi-
WRT smoothing-
There has been some suggestion of using "magic sinewaves" to do this.  This
consists of timing pulses to the steppers such that the result is close to a
sinewave.  I had a go at it, but it did not seem to help that much.  However, My
attempt shouldn't be constued as disproof of concept.  Try here:
http://www.tinaja.com/magsn01.asp
David

michael brown wrote:

> > Michael-
> > Glad things are working out.  I have been playing with floppy steppers,
> and they
> > are probably ok for my application, but where did you get the 'real stump
> > pullers' - I think I could afford $7 each ;-)
> > David
>
> I got them from a surplus store here in houston.  They seem to have come
> from some type of medical machine.  There is a nifty assembly attached that
> with about 15 or 20 little "fingers" in a line.  When the motor turns, the
> "fingers" move up and down in a moving sine wave type pattern.  They were
> used as a pump in some type of dialysis or bypass machine.
>
> I probably shouldn't have called them stump pullers, but they are
> significantly more powerful than the only slightly smaller floppy motors.
> They've had these for over a year, and they don't seem to be selling too
> fast.  However, some engineer, selling 8052-type development boards just put
> together a demo using one of those stepper motors, so they might dry up
> quick.  You just never know.
>
> I got them from Electronic Parts Outlet (aka EPO) here in houston.  If you
> need, I could get their phone number for you, or even get some and ship them
> to you.  They are used and asis, but the two that I got work fine.
>
> BTW, do you know any way to get them to quiet down or to turn more smoothly.
> I am already half stepping them, but that is just not as smooth as I'd like.
>
> michael
>
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