#include <Servo.h>

byte sensor_left_pin  = 11; 
byte sensor_right_pin = 10;
byte servo_right_pin = 9; 
byte servo_left_pin = 12; 

Servo servo_left; 
Servo servo_right;  

void setup() {
 pinMode(sensor_left_pin, INPUT); 
 pinMode(sensor_right_pin, INPUT);

 servo_left.attach(servo_left_pin); 
 servo_right.attach(servo_right_pin);  

 Serial.begin(9600); 
 Serial.println("Car is riding ...."); 
}

void loop() {
  int left_value = digitalRead(sensor_left_pin); 

  int right_value = digitalRead(sensor_right_pin); 

  if (left_value == 1  && right_value == 1) { 
    Serial.println("Go straight");
    servo_left.write(0); 
    servo_right.write(0); 
  }

  if (left_value == 0 && right_value  == 1) {
    Serial.println("Go right");
    servo_left.write(0);
    servo_right.write(90);  

  }

  if (left_value == 1 && right_value == 0) {
    Serial.println("Go left");
    servo_left.write(90); 
    servo_right.write(0);  
  }

  if (left_value ==  0 && right_value == 0) { 
    Serial.println("Line lost");
    servo_left.write(90) ; 
    servo_right.write(90);  
  }

  delay(2000); 

}