[TowerTalk] Re:Stepper Gearing source

[Pat Barthelow]

If you need gearing for the capacitor drive, try using the reduction gear 
assembly found in dot matrix printers platen drives, which are thrown away, 
or can be had for almost free..

73, DX, de Pat AA6EG/N6IJ  meamonte@hotmail.com
On the web: http://www.polkinghorn.org/n6ij, or   
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599 DX Drive Marina CA 93933

"For a successful technology, reality must
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for nature cannot be fooled."

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>From: alsopb <alsopb@gloryroad.net>
>To: "George K. Watson" <watson@sierracmp.com>
>CC: towertalk@contesting.com
>Subject: Re: [TowerTalk] tuner/stepper motors?
>Date: Mon, 27 Aug 2001 12:24:11 +0000
>
>
>George,
>
>What you say may be true in general.  However, I have a circuit from
>the PARALLAX stamp manual which shows a single stamp chip, a ULN2003
>driver chip, five resistors and a unipolar stepper motor are all that
>are required.  It appears to be able to drive stepper motors requiring
>up to 0.5 amps.
>
>The software is trivial -- about 10 lines of coding.  Easily fits
>within the 256 bits of memory in the cheapest stamp chip.
>
>But then again maybe it doesn't work.  However, the growing crowd of
>homebrew robot enthusiasts seems to have good luck with it.
>
>I'd be glad to forward the circuit diagram to anybody who is
>interested.
>
>A downside is that 6 wires are required to run it.
>
>73 de Brian/K3KO
>
>"George K. Watson" wrote:
> >
> > >> Anybody out there successfully used stepper motors to power variable
> > >> caps in remote tuners?  The ability to have good
> > >> precision/repeatability seems idea.  Chief problem seems to be
> > >> obtaining one with enough torque.
> > Torque can be generated through gearing. I imagine this would work quite
> > well.
> > I have some significant experience with both steppers and DC servo 
>motors
> > (though
> > not in this application) and either would work fine. Servos are harder 
>to
> > work with.
> > The control software is interesting and the external circuitry 
>(amplifiers)
> > required are expensive
> > and/or non-trivial to build.
> >
> > 73,
> > George K. Watson
> >
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