[simpits-tech] phidgits + Building Gauges

[fitchett]

That's a remarkable idea.  Photo Interrupters are cheap like borscht.
(sp?)  H21A1-ND from digikey is an example.  I've heard of stepper motors
with these integrated, but have never seen one.

Chester

> There's a small electronic device called a Photo Interrupter (PI) that could
> be used. This consists of an IR LED (Infra Red) on one side and a
> photo-transistor on the other. These are used in printers to indicate where
> the carriage is. All you need to do is put a small piece of plastic on the
> shaft of the stepper motor and each time this plastic piece passes between
> the two parts of the PI it cuts the IR to the transistor and signals the
> controller (PC, Basic Stamp, Phidgit etc) that the motor has turned one
> revolution. If you could set up a counting program then you keep track of
> the revolutions and hence the start point and any number of other points
> too.
> I got hold of a heap of old printers and stripped them of these devices and
> the stepper motors - ready for this sort of thing.
> Can anyone add to this theory ?
> Rod
> ----- Original Message -----
> From: Roy Coates <roy@flightlab.liv.ac.uk>
> To: <simpits-tech@simpits.org>
> Sent: Friday, October 25, 2002 5:34 AM
> Subject: Re: [simpits-tech] phidgits + Building Guages
>
>
> > On Thu, 24 Oct 2002 mysticz28@swbell.net wrote:
> >
> > > Gene Buckle wrote:
> > > >
> > > > The problem is that everyone and their brother has a neat method of
> > > > driving a stepper motor, but nobody says anything about *feedback*
> from
> > > > that motor.
> > >
> > > That's because steppers can't talk back (or they would be servos).
> > > Fortunately for them, you talk enough to take up their slack ;)
> > >
> >
> > I was led to believe that you CAN get feedback from a stepper.
> >
> > Roy.
> >
> >
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