LM393 with + inputs grounded and motor coils between - inputs and gnd.
Pullups required on outputs. Or LM358 (still with pullups to achieve Vih).
Maybe add two 1k resistors in series with each coil to avoid pumping the
supply if the motor is turned very fast.

Peter

On Fri, 28 Jun 2002, Roman Black wrote:

>Josh Koffman wrote:
>>
>(regarding rotary encoders for DIAL use)
>> There are ways to use a stepper motor as well, though I've never tried.
>> The ETC Expression lighting console uses just such an arrangement.
>
>I *really* like this idea! :o)
>Having replaced optos (darn unreliable things) in
>so many VCR optical "dial controls" the idea of using
>a $1 surplus stepper motor is brilliant. The detent
>"spring" will never wear out as it is the magnetic
>field of the motor, and with such low currents and
>heating the thing will work for about a zillion years,
>or until the bearings give out. Strong panel mounting,
>all-metal construction, solid bearings, hardened shaft,
>etc etc. Now cheap old-style steppers are available
>everywhere from the junk guys this sounds like a REALLY
>GOOD digital dial.
>
>Now any takers on the simplest circuit to connect one
>to 2 PIC digital inputs?? :o)
>-Roman
>
>--
>http://www.piclist.com hint: The list server can filter out subtopics
>(like ads or off topics) for you. See http://www.piclist.com/#topics
>
>
>

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics