Stepper Motor Driving

Discussion in 'General Electronics Chat' started by chrisw1990, Jan 16, 2013.

  1. chrisw1990

    Thread Starter Active Member

    Oct 22, 2011
    543
    41
    I have been considering multiple projects of late, which all include the use of a stepper motor of some sort small or large..
    but it has led to some questions.. which naturally led to research.. and then more questions :D
    i saw somewhere that id need say 40 V to drive a 5V coil.. which doesnt sound right.. and i wanted to get the considerable knowledge on here together to straighten out my thinking..
    so the scenario:
    PIC driving a stepper motor..
    Stepper motor: (link to ebay, just a random 1.8 degree motor with lots of information on the page)
    http://www.ebay.co.uk/itm/1-8-Degre...al_Components_Supplies_ET&hash=item460b441188
    and any old pic, 3.3 or 5V doesnt matter much..
    and the questions:
    1) what voltage do i need?
    2) what current am i going to require?
    3) whats microstepping really about and how do i do that with a pic?

    Thanks in advance!!
     
  2. SPQR

    Member

    Nov 4, 2011
    379
    48
    Hi,
    I'll answer just becaase I too am a newbie, and have spent the last year learning about steppers for THIS project.

    My advice is as follows:
    1. Choose the motor first based on the "strength" you need.
    "Strength" is measured in "oz-inches" or "Newton-meters"
    THIS motor is a strong one - 1.49 Newton-meters (212 oz-inches).
    THIS motor is a weak one - .23 Newton-meters (32.6 Oz-inches).
    HERE is a Newton-meter oz-inches converter.

    2. Get the voltage and current requirements off the motor.
    HERE you can see the smaller motor requires 12V at .33A.

    3. Choose your stepper controller once you have the V and A requirements. There are tons of them out there.

    4. Your stepper controller will have simple digital inputs to connect to your microcontroller.

    5. Program your microcontroller based on what you want to do.

    6. Microstepping is done on the stepper controller. You can set jumpers for full to 1/8th steps

    Steppers are a blast...you'll have lots of fun.
    Best of luck.

    Now we'll hear the REAL truth from the experts!:)
     
    chrisw1990 likes this.
  3. chrisw1990

    Thread Starter Active Member

    Oct 22, 2011
    543
    41
    i drove a stepper with simple EXOR gate and Stepper motor driver in first year of uni, but the guy was a dick and i never really learnt about the microstepping.. surely it must be possible to use MOSFETs to drive the stepper (cheaper surely?) and microstep with a DAC or pic pin?
     
  4. SPQR

    Member

    Nov 4, 2011
    379
    48
    You certainly can make your own "driver" with MOSFETs, and then create your own code to handle microstepping.
    But I think it will depend on your motor.
    If it's a small project - it's hard to beat a $14 stepper controller.
    If you search this site for "stepper driver" you'll see quite a few examples of stuff people have done.
     
  5. chrisw1990

    Thread Starter Active Member

    Oct 22, 2011
    543
    41
    awesome! thanks for the help! iv tried to find stepper drivers before with little luck (farnell UK dont seem to have many) so i sorta assumed they were a $$$/£££ thing!
     
  6. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,015
    1,531
    The voltage listed on a stepper motor really means nothing. It is the voltage that will make it turn, not really do any work. The working voltage of a stepper is found by multiplying the inductance by 32. This is from most all stepper sellers web sites.
     
  7. chrisw1990

    Thread Starter Active Member

    Oct 22, 2011
    543
    41
    how come? is there an equation/justification for that? not to doubt you, just be interested in why 32:)
     
  8. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,015
    1,531
    chrisw1990 and SPQR like this.
  9. geoffers

    Active Member

    Oct 25, 2010
    239
    6
    Hi,
    I think we could be on the same learning curve! I'm trying to drive a bipolar stepper at the moment, with varing results! I tried the l297/298 combination which works out at about £10, I've just got a panasonic AN44067A from RS and a Allegro A4982. They are quite small smd is the only issue, I put the first panasonic in upside down and got the magic white smoke! Got some more today so will let you know how I get on.
    Let us know how you get on.
    Cheers Geoff
     
  10. mhutchie1

    New Member

    Jan 21, 2013
    17
    14
    Check out the Arduino Stepper motor reference. Arduino also provides many examples of how to utilise this, recommending stepper motor models that can easily be purchased.

    http://arduino.cc/en/Reference/Stepper
     
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