Playing with a DVD drive stepper and an Arduino today. I mostly used the information from here

I omitted the Zener, from the circuit shown. And I’m driving stepper with a cut down version of his code:

const int motorPin1 =8;
const int motorPin2 =9;
const int motorPin3 =10;
const int motorPin4 =11;


void setup() {                
  // initialize the digital pin as an output.
  // Pin 13 has an LED connected on most Arduino boards:
  pinMode(motorPin1, OUTPUT);    
  pinMode(motorPin2, OUTPUT);    
  pinMode(motorPin3, OUTPUT);    
  pinMode(motorPin4, OUTPUT);     
}

void loop() {
 // HALF STEP  
 int motorDelay=10;
  digitalWrite(motorPin1, HIGH);
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, HIGH);
  digitalWrite(motorPin4, LOW);
  delay(motorDelay);
 
  digitalWrite(motorPin1, HIGH);
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, HIGH);
  digitalWrite(motorPin4, HIGH);
  delay(motorDelay);  
 
  digitalWrite(motorPin1, HIGH);
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, HIGH);
  delay(motorDelay);  
 
  digitalWrite(motorPin1, HIGH);
  digitalWrite(motorPin2, HIGH);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, HIGH);
  delay(motorDelay); 
 
  digitalWrite(motorPin1, LOW);
  digitalWrite(motorPin2, HIGH);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, HIGH);
  delay(motorDelay); 
 
  digitalWrite(motorPin1, LOW);
  digitalWrite(motorPin2, HIGH);
  digitalWrite(motorPin3, HIGH);
  digitalWrite(motorPin4, HIGH);
  delay(motorDelay); 
 
  digitalWrite(motorPin1, LOW);
  digitalWrite(motorPin2, HIGH);
  digitalWrite(motorPin3, HIGH);
  digitalWrite(motorPin4, LOW);
  delay(motorDelay); 
 
  digitalWrite(motorPin1, HIGH);
  digitalWrite(motorPin2, HIGH);
  digitalWrite(motorPin3, HIGH);
  digitalWrite(motorPin4, LOW);
  delay(motorDelay); 
}

Video:

Circuit diagram from link for reference: