line_follower.ino

enum INFRARED_SENSORS{IR_1 = 2, IR_2 = 3};
enum MOTORS{M1_enA = 5, M1_in1 = 9, M1_in2 = 10, M2_enB = 6, M2_in3 = 11, M2_in4 = 12};
// -------------------------------- defining pins -----------------------------------

extern int M1[3] = {M1_enA, M1_in1, M1_in2};
extern int M2[3] = {M2_enB, M2_in3, M2_in4};
// DC motor pins (motor driver pins)

int IR1_reading, IR2_reading;
int LEFT, RIGHT;

void moveLEFT(int motor1[3], int motor2[3]);
void moveRIGHT(int motor1[3], int motor2[3]);
void moveFORWARD(int motor1[3], int motor2[3]);
void moveBACKWARD(int motor1[3], int motor2[3]);
void STOP(int motor1[3], int motor2[3]);

void setup(){
    Serial.begin(9600);
  
    pinMode(IR_1, INPUT);
    pinMode(IR_2, INPUT);
    
  	for (int i = 0; i < 3; ++i){ // setting each Motor Driver pin as OUTPUT
    	  pinMode(M1[i], OUTPUT);
      	pinMode(M2[i], OUTPUT); 
    }
  
  	for (int i = 1; i < 3; ++i){ // setting Motor Driver's output pins as LOW
      	digitalWrite(M1[i], LOW);
      	digitalWrite(M2[i], LOW);
    }
	
  	analogWrite(M1[0], 180); 
  	analogWrite(M2[0], 180);    // Maximum speed for both DC Motors
  
  	IR1_reading = IR2_reading = 0;
	  LEFT = RIGHT = 0;

    TCCR0B = TCCR0B & B11111000 | B00000010 ;

}

void loop(){
 
	  IR1_reading = digitalRead(IR_1);
  	IR2_reading = digitalRead(IR_2);
  	
  	LEFT  = IR1_reading;
  	RIGHT = IR2_reading;
  	
  	while (LEFT || RIGHT){ // absence of light is detected
    		if (LEFT && RIGHT){
        		moveFORWARD(M1, M2);
      		}
      		else if(!LEFT && RIGHT){ // absence of light on LEFT and presence of light on RIGHT
        		moveLEFT(M1, M2);
      		}
      		else if(LEFT && !RIGHT){ // presence of light on LEFT and absence of light on RIGHT
      			moveRIGHT(M1, M2);
      		}
      
      		IR1_reading = digitalRead(IR_1);
      		IR2_reading = digitalRead(IR_2);

      		LEFT  = IR1_reading;
      		RIGHT = IR2_reading; 
        	// re-take the readings
    	}
    	STOP(M1, M2); // STOP if no strip is detected
}

void moveFORWARD(int leftMotor[3], int rightMotor[3]){
    	/* setting Left and Right motors to move forward*/
	  digitalWrite(leftMotor[1], HIGH);
  	digitalWrite(leftMotor[2], LOW);
  	
  	digitalWrite(rightMotor[1], HIGH);
  	digitalWrite(rightMotor[2], LOW);
  	Serial.println("Black Strip! Move Forward!");
}

void moveBACKWARD(int leftMotor[3], int rightMotor[3]){
    	/* setting Left and Right motors to move backward */ 
    	// has no use currently
	  digitalWrite(leftMotor[1], LOW);
  	digitalWrite(leftMotor[2], HIGH);
  	
  	digitalWrite(rightMotor[1], LOW);
  	digitalWrite(rightMotor[2], HIGH);
  	Serial.println("Obstacle! Move Backword!");
}

void STOP(int motorPins1[3], int motorPins2[3]){
    
  	for (int i = 1; i < 3; ++i){
      	digitalWrite(motorPins1[i], LOW);
      	digitalWrite(motorPins2[i], LOW);
    }
 	Serial.println("Stop!");
}
  
void moveLEFT(int leftMotor[3], int rightMotor[3]){
    	/* set Left motor on reverse and Right motor on forward to move Left */
	  digitalWrite(leftMotor[1], LOW);
  	digitalWrite(leftMotor[2], LOW);
  	
  	digitalWrite(rightMotor[1], LOW);
  	digitalWrite(rightMotor[2], HIGH);
  	Serial.println("Move Left!");
}

void moveRIGHT(int leftMotor[3], int rightMotor[3]){
    /* set Left motor on forward and Right motor on reverse to move Right */
	  digitalWrite(leftMotor[1], LOW);
  	digitalWrite(leftMotor[2], HIGH);
    
  	
  	digitalWrite(rightMotor[1], LOW);
  	digitalWrite(rightMotor[2], LOW);
  	Serial.println("Move Right!");
}