[Elecraft] Stepper Motor

[J F]

Actually Vic, I think a few folks might be interested
in this topic on the reflector (for a while). I, too,
have a number of steppers and would like to use them
for remote tweaking of a phased array.

I do know there are several controller kits available
and easily found. The question seems to be, what kind
of stepper do you have and exactly how do you wish to
control it? The are two options that seem to be the
most flexible, using a "Basic Stamp" or a PIC. 

If you have something like the PIC-EL kit from AmQRP
already, then the PIC option may be the easiest to
work with first. From what I've read a lot of the
robot folks seem to like the stamp approach.

Look forward to reading some other input, and maybe
some practical advice.
cheers,
Julius
n2wn


Message: 23
Date: Tue, 29 Mar 2005 10:31:12 -0800
From: Vic Rosenthal <vic at rakefet.com>
Subject: [Elecraft] OT - stepper motor question
To: Elecraft Reflector <elecraft at mailman.qth.net>
Message-ID: <42499EF0.9000604 at rakefet.com>
Content-Type: text/plain; charset=us-ascii;
format=flowed

I just know someone here can help me!  Please reply
off-reflector.

I recently had the opportunity to take apart a big old
Ricoh copy machine.  I recovered all kinds of neat
mechanical and electrical parts, inclucing 
bunches of solenoids, motors, etc.

One of the coolest is a motor marked 55SPM-25D5A
AX050032 30V 6.5 [ohms symbol]. Google gets nothing on
either of these numbers.

It has 6 wires coming out of it.  On the basis of
this, and the 'coggy' feel when I turn the shaft, I
think that it is a permanent-magnet unipolar stepper
motor.

I want to build a remotely tuned very QRO L-network
antenna tuner (I already have a large rotary inductor
and capacitor).  What I want to do is use this stepper
to turn the capacitor to preset positions.  Once the
capacitor is set, I will be able to drive the inductor
with a simple geared motor and just tune for lowest
SWR.

Reading material on stepper motor control systems has
my head spinning! Is 
there some kind of simple off-the-shelf controller
that I can get that will do most of the work?  What I
would REALLY like would be to just turn a local knob 
to adjust the capacitor (sort of like the way a selsyn
acts), but there may be other approaches.

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco