Programming a Stepper Motor for Reverse

Projects Programming
1

I used the code below to drive the stepper motor in one direction:

void blindsForward(){

 for (int increment = 0; increment < 56; increment++ ){
  digitalWrite(9, LOW);  //ENABLE CH A
  digitalWrite(8, HIGH); //DISABLE CH B

  digitalWrite(12, HIGH);   //Sets direction of CH A
  analogWrite(3, 255);   //Moves CH A
  
  delay(delaylegnth);
  
  digitalWrite(9, HIGH);  //DISABLE CH A
  digitalWrite(8, LOW); //ENABLE CH B

  digitalWrite(13, LOW);   //Sets direction of CH B
  analogWrite(11, 255);   //Moves CH B
  
  delay(delaylegnth);
  
  digitalWrite(9, LOW);  //ENABLE CH A
  digitalWrite(8, HIGH); //DISABLE CH B

  digitalWrite(12, LOW);   //Sets direction of CH A
  analogWrite(3, 255);   //Moves CH A
  
  delay(delaylegnth);
    
  digitalWrite(9, HIGH);  //DISABLE CH A
  digitalWrite(8, LOW); //ENABLE CH B

  digitalWrite(13, HIGH);   //Sets direction of CH B
  analogWrite(11, 255);   //Moves CH B
  
  delay(delaylegnth);

}
}

I was under the impression that I could reverse the polarity on one of the coils to reverse the direction of the motor by using the code below:

void blindsBackward(){   //This works by changing the polarity of the second coil only.

   digitalWrite(9, LOW);  //ENABLE CH A
  digitalWrite(8, HIGH); //DISABLE CH B

  digitalWrite(12, LOW);   //Sets direction of CH A
  analogWrite(3, 255);   //Moves CH A
  
  delay(delaylegnth);
  
  digitalWrite(9, HIGH);  //DISABLE CH A
  digitalWrite(8, LOW); //ENABLE CH B

  digitalWrite(13, HIGH);   //Sets direction of CH B
  analogWrite(11, 255);   //Moves CH B
  
  delay(delaylegnth);
  
  digitalWrite(9, LOW);  //ENABLE CH A
  digitalWrite(8, HIGH); //DISABLE CH B

  digitalWrite(12, HIGH);   //Sets direction of CH A
  analogWrite(3, 255);   //Moves CH A
  
  delay(delaylegnth);
    
  digitalWrite(9, HIGH);  //DISABLE CH A
  digitalWrite(8, LOW); //ENABLE CH B

  digitalWrite(13, LOW);   //Sets direction of CH B
  analogWrite(11, 255);   //Moves CH B
  
  delay(delaylegnth);

}

but I am getting movement in the same direction. I followed the coding from this:

2

I was under the impression that I could reverse the polarity on one of the coils to reverse the direction of the motor by using the code below:

No that is not the way to do it. You reverse the sequence of the coil powering to make it go backwards.

3

You reverse the sequence of the coil powering to make it go backwards.

Thank you good sir! I'm surprised I haven't tried that. It works, thank you very much.

The code is now as follows for reverse:

void blindsBackward(){                                       //This is done by revesing the sequence of the foward direction

 for (int increment_2 = 0; increment_2 < 56; increment_2++ ){
  digitalWrite(9, HIGH);  //ENABLE CH A
  digitalWrite(8, LOW); //DISABLE CH B

  digitalWrite(12, LOW);   //Sets direction of CH A
  analogWrite(3, 255);   //Moves CH A
   
  delay(delaylegnth);
  
  digitalWrite(9, LOW);  //DISABLE CH A
  digitalWrite(8, HIGH); //ENABLE CH B

  digitalWrite(13, HIGH);   //Sets direction of CH B
  analogWrite(11, 255);   //Moves CH B
  
  delay(delaylegnth);
  
  digitalWrite(9, HIGH);  //ENABLE CH A
  digitalWrite(8, LOW); //DISABLE CH B

  digitalWrite(12, HIGH);   //Sets direction of CH A
  analogWrite(3, 255);   //Moves CH A
  
  delay(delaylegnth);
    
  digitalWrite(9, LOW);  //DISABLE CH A
  digitalWrite(8, HIGH); //ENABLE CH B

  digitalWrite(13, LOW);   //Sets direction of CH B
  analogWrite(11, 255);   //Moves CH B
  
  delay(delaylegnth);

}
}
4

It is possible to reverse the direction of a stepper motor by reversing the polarity of one coil

Example step pattern for 1/2 stepping:

Normal:	 		Reverse Polarity
			of first Coil:
  1 2 3 4		  1 2 3 4
A + 0 - 0		E - 0 + 0 
B + + - -		D - + + -
C 0 + 0 -		C 0 + 0 -
D - + + -		B + + - -
E - 0 + 0		A + 0 - 0
F - - + +		H + - - +
G 0 - 0 +		G 0 - 0 +
H + - - +		F - - + +

Where 1&3 are one coil, 2&4 are the other coil

From the example pattern you can see that by reversing the coil that is 1&3, you reverse the sequence.