line-follower

const int sensorPin = 4;     // the number of the sensor pin
const int ledPin =  13;      // the number of the LED pin
int sensorState = 0;         // variable for reading the sensor status



void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(sensorPin, INPUT);
}



void loop() {
  // read the state of the sensor value:
  sensorState = digitalRead(sensorPin);
  // if the sensorState is HIGH:
  if (sensorState == HIGH) {
    digitalWrite(ledPin, HIGH);
  }
  else {
    digitalWrite(ledPin, LOW);
  }
}