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From: "Frank Bemelman"
References: <email@example.com> <firstname.lastname@example.org> <email@example.com>
Subject: Re: steppermotor as encoder -> presto, moterized pot.
Date: Sun, 6 Oct 2002 02:30:36 +0200
X-Newsreader: Microsoft Outlook Express 6.00.2600.0000
Organization: EuroNet Internet
NNTP-Posting-Date: 06 Oct 2002 00:30:48 GMT
"davidjudy" schreef in bericht
> "Richard Steven Walz" wrote in message
> > In article <firstname.lastname@example.org>,
> > Frank Bemelman wrote:
> > >Just had an idea, and I'm not planning to actually build
> > >something, but liked to share the idea - if it is an idea.
> > >
> > >What we want is a moterized pot for a homemade amplifier,
> > >so that it can be controlled both manually and by remotecontrol.
> > >Since we lack mechanical skills (not me of course) we want it to
> > >be mechanically simple. For cosmetic reasons we want the volume
> > >knob to turn as well, when using the remote.
> > >
> > >Okay. We use a size 17 steppermotor from an old 5.25 floppy
> > >drive. Some circuit to convert to logic levels, a PIC
> > >to decode etc. Now we have a signal to control a digital
> > >volume control. Easy.
> > >
> > >PIC also controls 4 outputs (steppers from floppydrives are
> > >often unipolar) if the remote wants to move the 'pot'. In this
> > >case, the software ignores the inputs, and simply increases
> > >or decreases the control of the *digital* pot, and stepping
> > >the motor with knob accordingly.
> > >Thanks,
> > >Frank Bemelman
> > -------------------------
> > Silly, use a digital pot! An up-dn counter with a clock which dials in a
> > resistive network tap to set a value, which goes to an op-amp in the
> > feedback loop.
> > If you just really want the knob to move mysteriously, use a stepper.
> > Okay for a tuner or such, but for a pot that's silly!
> > -Steve
> > --
> > -Steve Walz email@example.com ftp://ftp.armory.com/pub/user/rstevew
> > Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
> > http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public
> I think what the OP was saying is that he proposes using the stepper
> a) as an encoder when the volume control is operated manually. From there
> goes via a PIC to a digital volume control. Far from silly.
> b) as a motor to cosmetically move the knob when operated from the remote.
> Sounds like a neat idea to me. Elegant even. Maybe a non-silly person
> like to comment on the feasibility of what the OP proposed.
Ah, but we only have silly persons here at SED, which is good ;) Feasability
is not a problem - this *can* be build without too many problems. If I were
to build my own amplifier, I would certainly give it a shot.
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