bipolar stepper motor?

WhelzornWhelzorn Posts: 256
edited 2004-09-01 - 17:09:12 in Robotics
Well, I have this linear motion table thing (made by NEAT) that I found a year or so ago, and am wondering now what the hell to do with it. Anyway, I decided to first figure out how to use the thing, so I used a 5v transformer and figured out the pinouts, and that there is, indeed, a bipolar stepper motor inside. Anyway, this is the first bipolar stepper motor I have ever used and I am wondering how to use the basic stamp to drive this thing, without harming the basic stamp. I know that since its bipolar, I need to reverse the polarity on the coils inside to drive it, but I dont know how to do that without using 8 of my bs2's pins, and a load of transistors. So, I'm wondering if anyone has ever driven a bipolar stepper with the BS(1,2,whatever) and how they did it. I am aware that they make stepper motor drivers, but I dont know where to get these little buggers, and I would like to use only a bs2. I do have a microstepper I used to drive a unipolar, but it in enourmous, and probably won't fit into the size constraints of my project. Thanks for the help in advance!


  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2004-09-01 - 17:09:12
    The Bipolar stepper motor (even number of wires in pairs) uses a device similar to an H-bridge driver to interface with the BasicStamp.

    A Uni-polar stepper (odd number of wires - all the leads are tied to a common lead) can use the UNL3803A Darlington array to drive two steppers from the BasicStamp.

    The problem is how the Bipolar is switched (from supply and ground and vise-versa) -- both units use the same pattern to step through a rotation clockwise or counter-clockwise. The Nuts and Volts articles talk about a very good H-bridge chip that will control this directly from the Stamp as well as controlling an H-bridge. I am not sure, but you may need two of these chips for all the coils.

    There are a lot of good, small chips that will drive this directly from the BasicStamp - I depends on what is available cheaply, near you. You don't have to build a lot of controls or buy an expensive controller.

    G. Herzog in Taiwan

    Post Edited (Kramer) : 9/15/2004 2:30:14 PM GMT
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