/Declare L298N Dual H-Bridge Motor Controller directly since there is not a library to load.Define L298N Dual H-Bridge Motor Controller Pins/ #define speedPinR 3 // RIGHT PWM pin connect MODEL-X ENA #define RightDirectPin1 4 // Right Motor direction pin 1 to MODEL-X IN1 #define RightDirectPin2 2 // Right Motor direction pin 2 to MODEL-X IN2 #define speedPinL 6 // Left PWM pin connect MODEL-X ENB #define LeftDirectPin1 7 // Left Motor direction pin 1 to MODEL-X IN3 #define LeftDirectPin2 5 //Left Motor direction pin 1 to MODEL-X IN4

/From left to right, connect to D3,A1-A5 ,D10/ #define LFSensor_2 A2 #define LFSensor_3 A3 #define LFSensor_4 A4

#define SPEED 255 //motor in speed

char sensor[3]= {digitalRead(LFSensor_2),digitalRead(LFSensor_3),digitalRead(LFSensor_4)}; /read (sensor value string, 1 stands for black, 0 stands for white) i.e.010 means the first sensor(from left) detect white line, middle sensor detect black and right sensor detect white)/

void go_Advance(void) //Forward { digitalWrite(RightDirectPin1, HIGH); digitalWrite(RightDirectPin2,LOW); digitalWrite(LeftDirectPin1,HIGH); digitalWrite(LeftDirectPin2,LOW); }

void go_Left(void) //Turn left { digitalWrite(RightDirectPin1, HIGH); digitalWrite(RightDirectPin2,LOW); digitalWrite(LeftDirectPin1,LOW); digitalWrite(LeftDirectPin2,HIGH); }

void go_Right(void) //Turn right { digitalWrite(RightDirectPin1, LOW); digitalWrite(RightDirectPin2,HIGH); digitalWrite(LeftDirectPin1,HIGH); digitalWrite(LeftDirectPin2,LOW); }

void stop_Stop() //Stop { digitalWrite(RightDirectPin1, LOW); digitalWrite(RightDirectPin2,LOW); digitalWrite(LeftDirectPin1,LOW); digitalWrite(LeftDirectPin2,LOW); }

/*set motor speed */

void set_Motorspeed(int speed_L,int speed_R) { analogWrite(speedPinL,speed_L); analogWrite(speedPinR,speed_R); }

void setup() { pinMode(speedPinL,OUTPUT); //left motor PWM pin pinMode(speedPinR,OUTPUT); //rignt motor PWM pin pinMode(RightDirectPin1,OUTPUT); //left motor direction pin1 pinMode(RightDirectPin2,OUTPUT); //left motor direction pin2 pinMode(LeftDirectPin1,OUTPUT); //right motor direction Pin 1 pinMode(LeftDirectPin2,OUTPUT); //right motor direction Pin 2

/*line follow sensors */ pinMode(LFSensor_2,INPUT); pinMode(LFSensor_3,INPUT); pinMode(LFSensor_4,INPUT); Serial.begin(9600); }

void auto_tracking()

{ if ((sensor[0]==0 and sensor[1]==0 and sensor[2]==0) or (sensor[0]==0 and sensor[1]==0 and sensor[2]==1) or (sensor[0]==0 and sensor[1]==1 and sensor[2]==1)) { //The black line is in the right of the car, need right turn go_Right(); //Turn right set_Motorspeed(0,SPEED); delay(200); stop_Stop(); }

if ((sensor[0]==1 and sensor[1]==0 and sensor[2]==0) or (sensor[0]==1 and sensor[1]==1 and sensor[2]==0)) { //The black line is on the left of the car, need left turn go_Left(); //Turn left set_Motorspeed(SPEED,0); delay(200); stop_Stop(); }

if (sensor[0]==1 and sensor[1]==1 and sensor[2]==1) { stop_Stop(); //The car front touch stop line, need stop set_Motorspeed(0,0); stop_Stop(); }

if (sensor[0]==0 and sensor[1]==1 and sensor[2]==0) { go_Advance(); //Continue forward set_Motorspeed(100,100); delay(100); }

}

void loop () { auto_tracking(); }