Arduino/Projects/28BYJ Stepper/first_test/first_test.ino

// This Arduino example demonstrates bidirectional operation of a 
// 28BYJ-48, which is readily available on eBay, using a ULN2003 
// interface board to drive the stepper. The 28BYJ-48 motor is a 4-
// phase, 8-beat motor, geared down by a factor of 68. Onint e bipolar 
// winding is on motor pins 1 & 3 and the other on motor pins 2 & 4. 
// Refer to the manufacturer's documentation of  Changzhou Fulling 
// Motor Co., Ltd., among others.  The step angle is 5.625/64 and the 
// operating Frequency is 100pps. Current draw is 92mA.  In this 
// example, the speed and direction of the stepper motor is determined 
// by adjusting a 1k-ohm potentiometer connected to Arduino pin A2. 
// When the potentiometer is rotated fully counterclockwise, the motor 
// will rotate at full counterclockwise speed. As the potentiometer is 
// rotated clockwise, the motor will continue to slow down until is 
// reaches its minimum speed at the the potentiometer's midpoint value . 
// Once the potentiometer crosses its midpoint, the motor will reverse 
// direction. As the potentiometer is rotated further clockwise, the speed   
// of the motor will increase until it reaches its full clockwise rotation 
// speed when the potentiometer has been rotated fully clockwise.
////////////////////////////////////////////////

//declare variables for the motor pins
int motorPin1 = 8;	// Blue   - 28BYJ48 pin 1
int motorPin2 = 9;	// Pink   - 28BYJ48 pin 2
int motorPin3 = 10;	// Yellow - 28BYJ48 pin 3
int motorPin4 = 11;	// Orange - 28BYJ48 pin 4
                       // Red    - 28BYJ48 pin 5 (VCC)

int motorSpeed = 0;     //variable to set stepper speed
int potPin = 2; 	//potentiometer connected to A2
int potValue = 0; 	//variable to read A0 input


//////////////////////////////////////////////////////////////////////////////
void setup() {
 //declare the motor pins as outputs
 pinMode(motorPin1, OUTPUT);
 pinMode(motorPin2, OUTPUT);
 pinMode(motorPin3, OUTPUT);
 pinMode(motorPin4, OUTPUT);
 Serial.begin(9600);
}

//////////////////////////////////////////////////////////////////////////////
void loop(){

 //potValue = analogRead(potPin);     // read the value of the potentiometer
 Serial.println(potValue);          // View full range from 0 - 1024 in Serial Monitor
 if (potValue < 535){               // if potentiometer reads 0 to 535 do this
   motorSpeed = (potValue/15 + 5);  //scale potValue to be useful for motor
   clockwise();                     //go to the ccw rotation function
 }
 else {                             //value of the potentiometer is 512 - 1024
   motorSpeed = ((1024-potValue)/15 + 5); //scale potValue for motor speed
   counterclockwise(); //go the the cw rotation function
 }
}

//////////////////////////////////////////////////////////////////////////////
//set pins to ULN2003 high in sequence from 1 to 4
//delay "motorSpeed" between each pin setting (to determine speed)

void counterclockwise (){
 // 1
 digitalWrite(motorPin1, HIGH);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, LOW);
 delay(motorSpeed);
 // 2
 digitalWrite(motorPin1, HIGH);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, LOW);
 delay (motorSpeed);
 // 3
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, LOW);
 delay(motorSpeed);
 // 4
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin4, LOW);
 delay(motorSpeed);
 // 5
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin4, LOW);
 delay(motorSpeed);
 // 6
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin4, HIGH);
 delay (motorSpeed);
 // 7
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, HIGH);
 delay(motorSpeed);
 // 8
 digitalWrite(motorPin1, HIGH);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, HIGH);
 delay(motorSpeed);
}

//////////////////////////////////////////////////////////////////////////////
//set pins to ULN2003 high in sequence from 4 to 1
//delay "motorSpeed" between each pin setting (to determine speed)

void clockwise(){
 // 1
 digitalWrite(motorPin4, HIGH);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, LOW);
 delay(motorSpeed);
 // 2
 digitalWrite(motorPin4, HIGH);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, LOW);
 delay (motorSpeed);
 // 3
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, LOW);
 delay(motorSpeed);
 // 4
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin1, LOW);
 delay(motorSpeed);
 // 5
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin1, LOW);
 delay(motorSpeed);
 // 6
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin1, HIGH);
 delay (motorSpeed);
 // 7
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, HIGH);
 delay(motorSpeed);
 // 8
 digitalWrite(motorPin4, HIGH);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, HIGH);
 delay(motorSpeed);
}