Line_tracking_car.ino

//Line Tracking IO define
#define LT_R !digitalRead(10)
#define LT_M !digitalRead(4)
#define LT_L !digitalRead(2)

#define ENA 5
#define ENB 6
#define IN1 7
#define IN2 8
#define IN3 9
#define IN4 11

#define carSpeed 170

void forward(){
  analogWrite(ENA, carSpeed);
  analogWrite(ENB, carSpeed);
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
  Serial.println("go forward!");
}

void back(){
  analogWrite(ENA, carSpeed);
  analogWrite(ENB, carSpeed);
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH);
  Serial.println("go back!");
}

void right(){
  analogWrite(ENA, carSpeed);
  analogWrite(ENB, carSpeed);
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
  Serial.println("go right!");
  
}

void left(){
  analogWrite(ENA, carSpeed);
  analogWrite(ENB, carSpeed);
  digitalWrite(IN1,LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH); 
  Serial.println("go left!");
} 

void stop(){
   digitalWrite(ENA, LOW);
   digitalWrite(ENB, LOW);
   Serial.println("Stop!");
} 

void setup(){
  Serial.begin(9600);
  pinMode(LT_R,INPUT);
  pinMode(LT_M,INPUT);
  pinMode(LT_L,INPUT);
}

void loop() {

if (LT_M){
  forward();
  
}   
 else if(LT_L) {
    left();
    while(!LT_M);  
  }
  else if(LT_R) {
right();
    
    while(!LT_M);
  }
    
   }