Stepper motor controllers

Model Railroader Electronics and DCC
1

Has anyone seen an inexpensive bipolar stepper motor controller?

I’ve got a couple good motors, out of old printers, and want ot use one for a turntable drive - 200 steps per revolution, 10 tooth/inch cog and belt, just need a way to run it CW or CCW, fast or slow or single step - anticipate manual / eyeball control for alignment.

2

I had the same idea before I bought my Walthers tt. Here is a stepper motor control kit that might work.

http://www.allelectronics.com/make-a-store/item/MK-8096/USB-STEPPER-MOTOR-DRIVER/CONTROLLER-KIT/1.html

-Bob

3

With the cost of stepper drive controllers being what they are. Up to $100.00 and more.

If you don’t use the full features of the stepper motor why use it?

A simple DC motor will work just as well with a much lower cost. A simple gear reduction would work just fine. DPDT switch for direction control.

4

Well, for one, I’ve got the stepper motor, and only some old DC-71 style motors of doubtful performance - and they would need the gear reduction, drive train, etc. - whereas I already have the stepper with a 10 tpi cog and a big enough 10 tpi cog belt to fit around the Heljan string drive V-pulley. It fits quite well, drives without slipping, and gives a fair amount of reduction just from the about 1/4" dia. 20 tooth cog to the approx. 4" dia. pulley.

The controllers I’ve seen allow easy switch inputs for CW/CCW rotation, speed selection (using resistors to set the speeds desired), and single step nudging - a good solution for manual control.

I’m curious: what stepper motor features that would affect turntable operation am I not contemplating using?

5

would you be interested in building your own controller using this H-bridge?

6

You need to determine if your motor is bipolar or unipolar - Rob Paisley has circuits for both types on his page. Should be able to put something like this together for $10-$15, or you can order a complete kit from Rob for $26.

http://home.cogeco.ca/~rpaisley4/Stepper2012Unipolar.html

http://home.cogeco.ca/~rpaisley4/Stepper2012Bipolar.html

–Randy

7

Rob’s circuits do work. I have made some.

I bought his parts for the DCC amp meter and it works just fine.

Rich

8

The motor I want to use is bipolar. Paisley’s board looks good - and it’s only $2 more assembled so I’ll take the easy way out. My electronics training was Navy basic avionics and also airborne sonar and other ASW gear - definitely tube theory time,with just one week at the end on transistors: when I got to a helo squadron the AQS-10 dipping sonar was discrete transistors on circuit boards. The only thing I ever fixed was my Dad’s old Magnavox radio/phono console, that used the speaker field coil (!) as a power supply filter choke! And I was aircrew - never worked in the shop, but did end up behind an M-60 over North Vietnam:

http://raunchyredskins.us/Operations/IG%2069%20Down/IG_69_Down_Caple.htm

http://raunchyredskins.us/Operations/IG%2069%20Down/IG_69_Down.htm (pictures)

Note: the definitely non-PC squadron nickname came from our radio call sign, “Indian Gal” - at least we didn’t get “Tasty Nostril” like the Air Force EC-121 guys flying SAM watch at 60 feet or so, leaving four prop wakes on the water