energized stepper jitter / non-functional

Using Arduino Motors, Mechanics, Power and CNC
1

I am unsure why my stepper motor is not functioning properly.
When energized, the shaft has resistance and shakes / jitters / does not complete a full rotation.

Supplies:

  • 12V bipolar (4-wire) stepper is from sparkfun (titled Small Stepper Motor).
  • EasyDriver Stepper Motor Driver.
  • 12V battery adapter.
  • breaboard
  • jumper cables
  • Arduino Uno

I have built the circuit exactly as shown here: Easy Driver Examples

As well, I have used the following code:

void setup() {                
  pinMode(8, OUTPUT);     
  pinMode(9, OUTPUT);
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);
}

void loop() {
  digitalWrite(9, HIGH);
  delay(1);          
  digitalWrite(9, LOW); 
  delay(1);          
}

steps: power motor, power arduino, upload code.
The motor steps back and fourth rapidly.
If the delay is changed to 10 ms, the steps are slower.
I notice a slight dimming on the easy driver that corresponds with the steps.

I am positive the wiring is correct as shown in the diagram.
It is my assumption that I have somehow damaged the motor or easy driver.
Is there a way to confirm? Thanks for any advice in advance.

-taylor

2

What kind of 12V supply are you using? Are you sure it can supply enough current?

3

Most likely a power supply problem.
Please provide a link to the motor.
What did you set as the current limit on the Easydriver?

4

Did you try adjusting the current limit pot?

From SparkFun:

Potentiometer

The potentiometer on board is included to allow users the ability to select the max current provided to the motor. It ranges from 150mA to 750mA. This will require you to be aware what current range your motor can handle – check the motor’s data sheet for the current settings.
If you can’t find this information, have no fear – you can still find the proper setting for the potentiometer. First, set it to the lowest setting of the potentiometer. Keep in mind that the potentiometer is delicate, so be careful to not force the potentiometer past the mechanical stops when turning it. Once you have the motor being driven at a slow, yet steady speed, slowly turn the potentiometer and pay attention to the motor’s behavior. You should find a sweet spot where the motor doesn’t skip or jerk between steps.

5

rolyat:
The motor steps back and fourth rapidly.
If the delay is changed to 10 ms, the steps are slower.
I notice a slight dimming on the easy driver that corresponds with the steps.

Have you adjusted the current limit on the Easydriver to match the requirement of your motor. The Easydriver has a max current of 750mA so it is only for low-current motors.

Post a link to the datasheet for your motor.

Start your tests with very slow steps - perhaps 100msecs between steps, or even more.

...R
Stepper Motor Basics
Simple Stepper Code

6

Post a link to the motor please, don't make us waste time googling it, that's your job and you've
obviously already done it!