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Stepper Motor Question — Parallax Forums

Stepper Motor Question

neotericneoteric Posts: 144
edited 2006-01-05 19:23 in Robotics
I am rebuilding an old heathkit robot, replacing the components with a basic stamp 2.5 with boebot board.

I am new to all of this, but have a good understanding.· This question is if anyone has worked with this type of stepper motor, and how to add a 12v item to the Stamp.· The stepper motor is 12v, and was made by ECM Motors, Inc., which had no data on its old motors.

it has six wires coming from the base, 3 on each side.· (2 sets of 3)· White Black and Yellow.· (total of six wires)

I understand in general, from reading all day, the concept of how a stepper motor works.· there are a total of eight stepper motors, but I am currently only interested in the two that are as I just described, as they are almost impossible to get to.· The others I will probably replace with the single line stepper sold here.

Anybody got knowledge or an educated guess on what a schematic might be.

PS (I understand that the Stamp puts out a regulated 5v, so I will be using an external supply for the motor.· But I want to control it's lines from the stamp.)

Thanks to anyone who helps me.

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-12-30 07:55
    Hello,

    ·· Is this a HERO-1?· If so, it's a classic and legendary robot which would be worth a lot more restored.· If you're really going to rebuild it though, then schematics should be easy to find via Google, since these are collectors items, and I have seen more than a few web pages with lots of information.

    Stepper Motors with·6 wires are usually Unipolar 4-phase with two common wires.· Should be easy enough to find out with an Ohm-meter.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • neotericneoteric Posts: 144
    edited 2005-12-30 13:06
    Thanks for your reply

    yes, its a hero 1.· Schematics are not available.·At least, not in the three monthes that I have been trying to get them.· This one was pretty crushed, and has no panels.· Once restored, if even possible, it is still less capable then it might be with a stamp.· It is more valuable to me as a learning tool.· Several folks are redoing thiers with various means.· Thanks for the help on the stepper motor.· I am pretty sure it is a 4 phase.·· What I am really unsure of, is:· If it is, how do I wire it....· IT IS 12V.· I am pretty sure how to do it with the 5V ones....· I have searched on this, but am still unclear.....

    ·
  • John R.John R. Posts: 1,376
    edited 2005-12-30 13:35
    Manuals and schematics are available for a fee from:

    http://www.hero-1.com/Broadband/index.htm

    The individual (Robert Doerr of www.robotswanted.com)·has purchased all parts and copywrites from Zeneth.· I suspect he may be somewhat diligent in making sure this stuff doesn't become too easy to get...

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    John R.

    8 + 8 = 10
  • neotericneoteric Posts: 144
    edited 2005-12-30 14:02
    Thanks for trying to help with that info.

    Really, I swear.· I have tried to get schematics.· I have not been able to get them.· Robert's stuff has been packed up from his move for several monthes.· I've gone this route.

    And a dozen others.· I'm not trying to restore the Hero 1 to it's original state.· I'm not a ROBOT collector.· (For those concerned, I am not destroying any of the Hero1 parts...)· Understand that that many of the parts were deystroyed.· There are no outside panels, and those are not available.

    Think more of building a souped up vehicle as opposed to restoring a classic car.

    Is there any way anybody can help me with my actual question?· Which is how do I switch a 12v device on and off....· Please review my original post if you can help...·
  • danieldaniel Posts: 231
    edited 2005-12-30 14:50
    Start with the documentation for Parallax's stepper motor (http://www.parallax.com/detail.asp?product_id=27964) or Stampworks Experiment 26 (http://www.parallax.com/html_pages/downloads/sw/sw.asp); note that this motor is a unipolar and yours may not be.· The circuits in the doc starts to show the way.

    Then go to http://sxlist.com/techref/io/steppers.htm·and follow the link called Wiring to sort out exactly what stepper motor you have (at least figure out how it should be wired).

    From there, you can also follow the links to Jones' Stepper Motor tutorial (http://www.cs.uiowa.edu/~jones/step/); he will explain it all, and give some sample circuits.

    Once you figure out whether you have a unipolar or bipolar motor, then you just need a circuit to control it.· For a unipolar, the ULN2003 type of circuit in the Parallax stepper motor doc would suffice, or take a look at Roman Black's stepper controller (http://sxlist.com/techref/io/stepper/linistep/index.htm), and there are a handful of good stepper motor drivers.· If you need to drive a bipolar motor, you might start with the power transistor circuit explainations in an early Nuts & Volts column (http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv6.pdf).

    Daniel
  • neotericneoteric Posts: 144
    edited 2005-12-31 11:42
    Daniel,

    Thanks.· The stepper motor wiring page, really helped.· the early nuts and bolts article clinched it.· I had googled, but somehow never hit on the sxlist page you provided.· Thats a biggie, as it appears there are several motors of different types in this.·· I had been all over the parallax site, but somehow missed that article.· I am on my way now at least.··I went to the local electronics store last night and picked up a darlington and a ULN2203.·(as of yesterday morning, i didnt even know what they were...· I am new to all this.)· ·I also picked up a solid state relay, since one of the motors is a plain 12v dc.· This will at least let me begin.

    Thanks for taking the time to walk me through getting started!· today I hope to make some progress....
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2005-12-31 15:50
    neoteric -

    Just as a matter of curiosity, is the Darlington driver a ULN2203 or a ULN2003? If the former, who makes it?

    Thanks

    Regards,

    Bruce Bates
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2005-12-31 16:41
    I would really consider measuring the resistance on the stepper motor coils before you decide to use a ULNxxxx. They are rated at 500ma overall and you may have much more powerful stepper motors.

    With ohm's law, you can easily estimate their ampreme rating at 12 volts.

    Additionally, while Darlingtons are nifty, they have the one drawback of being two conventional BJT transistors in one package. They serves to make them more sensistive to overheating than other devices.

    It appears that with the improvements in MOSfets, you can easily use individual MOSfets to drive those steppers quite nicelly. And, they do have protective diodes in some for inductive flyback.

    Bruce Bates - you are quite right about kindness being important. Thanks for mentioning it to me.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • neotericneoteric Posts: 144
    edited 2005-12-31 22:51
    Bruce,

    yeah.gif·my mistake.· It is a 2003.

    Typo.


    ·
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-01-02 16:29
    I believe that the ULN2003 has only 7 lines and the other has 8.

    From what I understand, these chips were drivers for dot matrix printers in their original use and many had a 5X7 matrix, so there was no need for the 8th bit.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-01-02 16:40
    If you do indeed have a bipolar stepper then you can drive it with an L293D -- and use the same code that you would normally use with ULN2803 and unipolar motor. StampWorks 2.0 has been updated for the PDB which now has the L293D; you might download that for ideas on driving the stepper.

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    Jon Williams
    Applications Engineer, Parallax
  • neotericneoteric Posts: 144
    edited 2006-01-05 19:23
    Thanks for all your help!· I got it working!· It moves around the living room.·

    I really, really appreciate the answers.· Several great solutions!· Looks like this old robot may have a new soul.
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