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mrebuth · Sep 4, 2007, 08:16 PM

I don't know if this is the correct place to be asking this, I'm new to here. But, I am looking make a simple driver circuit for a unipolar stepper motor with a 7.5 degree step. Does anyone know how I would go about doing this?

KISS · Sep 4, 2007, 08:44 PM

Here is what looks like a decent link: http://www.electronics-lab.com/proje...17/stepper.pdf

It's hard enough to get commercial products to work as you intended when combined with a controller.

I've worked with one of these: 2 phase bipolar Motor Drivers, stepper motor driver, motion control drivers, step motor driver

PS: You really didn't give enough info such as Voltage and amps/phase.

mrebuth · Sep 4, 2007, 08:55 PM

Sorry, more info, it's a 2-2 phase, drive voltage is 24V, coil resistance is 30ohms, is it possible to just use a ULN2003A to drive it? And, I am looking at the data sheet and it lists data for unipolar and bipolar, though it is a unipolar, and it says 800mA for bipolar but is blank for unipolar. If it helps further, it is a P55l-048 by NMB-MAT

Also, I am trying to use this in conjunction with a PIC18f452. I don't know if it is compliant but it's what I found lying around in the lab at school.

KISS · Sep 4, 2007, 09:25 PM

If you look at the data sheet for the ULN2003, it won't handle the current and the max current depends on the number of active drivers and duty cycle.

Unipolar basically means you can put a positive voltage to the center tap of the winding.

Bipolar means you have to double the unipolar voltage and provide a mechanism to reverse the polarity to the winding (H-Bridge). The center tap isn't used.

In the link, I gave you, it you delete all the junk, there is not much left.