New A4988 and erratic stepper motor movement

nodakbassmaster · April 9, 2012, 7:37pm

Ben:

A little more resolution would have allowed me to see the solder joints better (you can just attach pictures directly to your forum post rather than using an image hosting site that is probably resizing them), but the joints look pretty good as far as I can tell.

I can’t tell if you are using a pull-up or pull-down resistor to give your switch a default value in the NC state. I also can’t see your pictures clearly enough to really trace which wires are going where, so it’s hard to determine if there is a problem there.

Ultimately, it might be best to just wait for your replacement driver to arrive to see if the problems go away. However, if you want to keep trying to test your current driver, I think you should simplify things down further.

Connect one side of your switch to ground and the other to pin 12, and use the Arduino’s internal pull-up to give it a default high NC state. Then simplify your code to:
#define enablePin 5
#define stepPin 6
#define dirPin 7
#define buttonPin 12

void setup()
{
  pinMode(enablePin, OUTPUT);
  digitalWrite(enablePin, LOW);

  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT);
  digitalWrite(buttonPin, HIGH);  // enable internal pull-up 

  pinMode(stepPin, OUTPUT);
  digitalWrite(stepPin, LOW);
  pinMode(dirPin, OUTPUT);
  digitalWrite(dirPin, LOW);
}

void loop()
{
  while (digitalRead(buttonPin));  // wait here while button is not pressed
  delay(10);  // debounce button press
  while (!digitalRead(buttonPin));  // wait here while button is pressed
  
  digitalWrite(stepPin, HIGH);
  delay(10);
  digitalWrite(stepPin, LOW);
}
Now every every time you push and release the button, the Arduino will generate a single 10 ms high pulse on the step pin, advancing the driver by one step. What happens if you run this code without pushing the button at all? What changes whenever you push and release the button?

- Ben

This works perfectly with the new board.

Swapped the original board in without changing any connections on the breadboard and while it will step to other lights now, i am still getting erratic random flashing lights bouncing between pins, multiple lights lit up when there should be only one and the illuminated lights are blinking as well…

Ben · April 9, 2012, 8:41pm

So just to be clear, new board works as you expect in your setup while the original board does not?

- Ben

ryantm · April 9, 2012, 8:56pm

It looks like you happened to run into our forum’s total file size limit. Sorry for the inconvenience. I made the file limit much higher, so you should be able to post your picture now.

- Ryan

nodakbassmaster · April 9, 2012, 9:30pm

Yes, the new board worked as expected with the LEDs, I will try it with the motor a little late when I get time, but I have no reason right now to doubt it. The original still does not work right.

Thank you, I will upload the picture when I get home from work. I had to leave and its no the home computer.

Ben · April 10, 2012, 12:51am

I’m very happy to hear that the new board is functioning for you, and I’m sorry that you spent so long trying to get working what appears to be a defective board. Please note that we test all of these drivers before they ship, so your original driver was very likely working at one point, but your setup seems sound (though the problems could be the result of something as simple as static zap or momentarily connecting the wrong wire someplace). Since it’s so unclear what went wrong, we should be able to at least offer you a discount on another replacement if you email us and reference this forum thread.

- Ben

nodakbassmaster · April 10, 2012, 1:56am

Email sent, thanks again for your time and assistance.