Simple stepper motor project

Discussion in 'The Projects Forum' started by Brian Krupicka, Oct 25, 2017.

  1. Brian Krupicka

    Thread Starter New Member

    Nov 1, 2014
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    I am trying to help my grandson with a very simple stepper motor project.

    Two separate operations:

    1) Toggle a switch ON and have the stepper motor continually rotate in one direction.

    Once a 555 pulse generator is powered on, it would pulse a multi-poll relay, which would operate the stepper motor.



    2) Press a button and have the stepper motor index.

    Each time the push button is activated the multi-poll relay would operate the stepper motor.



    Would this work? Any additional comment would be helpful.

    Thank you
    Brian K
     
  2. shortbus

    AAC Fanatic!

    Sep 30, 2009
    5,812
    3,310
    Don't see it working. Stepper motors need a driver, to give the correct sequence of signals to the motor. While there are many circuits out there to make them, many don't work. The fastest and most inexpensive that actually work, are really cheap on Ebay. Like this one, just the first that came up in Google, may even be cheaper ones. https://www.ebay.com/i/261823467014?chn=ps&dispItem=1
     
  3. Brian Krupicka

    Thread Starter New Member

    Nov 1, 2014
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    Thank you for your comments. I am learning a great deal.
    The project is to rotate, in one direction at a low speed, a model train engine turntable.
    I will use a 555 pulse generator (set to a ½ second) to drive the “Step” pin on an Easy Driver.
    This will be accomplished by pressing and holding an N/O push-button, until the engine turntable reaches the desired position. (Note: Micro stepping will come later, once, I get the basic operation working. However, I feel MS1 and MS2 maybe will be wired to +5V.)
    A second on/off toggle switch connected to the “DIR” pin on an Easy Driver will control the direction.
    See attached drawing
    Comments are greatly appreciated.
    Thank you
    Brian K
     
  4. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
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    That ought to work.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
    16,409
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    Is it a 12vdc on the motor spec?
    Max.
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
    16,409
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    Also evidently the maximum motor phase current for the easy driver is 750ma, many motors exceed this.
    Max.
     
  7. Brian Krupicka

    Thread Starter New Member

    Nov 1, 2014
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    This is the stepper motor I ordered. Do you see any issues?
    The stepper motor is:
    Model: ROB-09238
    Manufacturer: SparkFun
    Stepper Motor with Cable Features:
    • Step Angle: 1.8° + /- 5%
    • 2 Phase
    • Rated Voltage : 12V
    • Rated Current : 0.33A
    • Holding Torque : 2.3kg per cm (0.23N.M)
    • 5mm Diameter Drive Shaft
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Looks OK.
    Max.
     
  9. Brian Krupicka

    Thread Starter New Member

    Nov 1, 2014
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    Thank you for your assistance.
    I will send summary upon completion.
    Brian K
     
  10. philba

    Active Member

    Aug 17, 2017
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    If you haven't already ordered the stepper driver, consider using one of the pololu drivers, they are loads cheaper and use the same chip as the big easy driver. The main difference is the BED has a voltage regulator on it.

    I'm sure other will disagree but I would tackle this project with a microcontroller - an arduino nano is really cheap and works great. The problem I have with every stepper driver+motor I've ever used is it takes some experimentation to get everything working (step rate, pulse width, etc). And if you will be doing microstepping, you will definitely want to experiment to find the sweet spot of the driver+motor. With a micro it's quick to make changes, with a 555 you have to fiddle with component values. Not that it's a bad thing, just takes me longer to get things where I want them.
     
  11. Brian Krupicka

    Thread Starter New Member

    Nov 1, 2014
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    0
    Thank you for the recommendation and response.
    We will try this driver as well with the 555 approach, since we do not have the expertise for programing a micro-controller.
    Brian K
     
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