Adafruit motor shield - Sparkfun stepper wiring?

Using Arduino Motors, Mechanics, Power and CNC
1

Hi,

I'm using the Adafruit motor shield and the Sparkfun stepper. I'm trying to wire the motor up correctly. Can anyone tell me the correct wiring? See attached.

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2

So long as you make sure one winding goes to one channel and the other to the other channel it will be fine. You can use a multimeter to check which motor wires are connected by a winding.

It the motor goes the wrong way simply reverse one of the two windings.

3

Thanks for the reply. I got it wired right in the end. However the speed is rubbish - nothing above 20rpm. I think it's power related even though i'm feeding it the 12v it says it needs.

4

With stepper motors to hold steps at speed you have to accelerate and decelerate the stepping frequency to allow the mass of the motor to keep up - if you were just going from stationary to 20rpm instantly that would explain its failure to manage any faster.

If you feed steps from standstill at a high rate the rotor won't be able to make the first step before the next pulse arrives owing to inertia.

I would expect something more like 200rpm to be readily achievable with an accelerating step rate. I think IIRC there's an AccelStepper library?

5

Thanks for the tip.

I'm still not getting any kind of speed out of the motor. Here's the code i'm now using:

#include <AccelStepper.h>
#include <AFMotor.h>

AF_Stepper motor1(200, 1);

void forwardstep1() {  
  motor1.onestep(FORWARD, DOUBLE);
}
void backwardstep1() {  
  motor1.onestep(BACKWARD, DOUBLE);
}

AccelStepper stepper1(forwardstep1, backwardstep1);

void setup()
{  
    stepper1.setMaxSpeed(300.0);
    stepper1.setAcceleration(15.0);
    stepper1.moveTo(1000);

    
}

void loop()
{
    if (stepper1.distanceToGo() == 0)
	stepper1.moveTo(-stepper1.currentPosition());
    stepper1.run();

}

It's a version of one of the examples. It's the only one that would work with a bit of tweaking. The result i get is as follows. It speeds up to about 20rpm then wiggles back and forth - then it obviously reached it's distance and does the same in the other direction.

Any other tip? With the code i'm using what would the expected results be?

Thanks

6

Just a suggestion, but try setting your setMaxSpeed(700); setSpeed(700); and most importantly setAcceleration(1000). An accellof 15 is soooo slow and I am sure you never really get to speed before you reach your final position!

Also, make sure you are using the latest AccelStepper library as I have found some significant changes in the different version.

Finally, it is common and recommended to drive a stepper motor system with 4 to 6 times the rated voltage of the coils. I believe this has to do with the pulsed nature of the driving circuitry (good description of all matters Stepper Motor related at http://www.geckodrive.com/ark-2/support.html ), but in any case, if the coils are rated 12V try driving it with as high a voltage as the Motor Shield will take, I think 36VDC.

-Paul