const int led = 13;
void setup() {
  Serial.begin(9600);
  pinMode(led, OUTPUT);
}
void loop() {
  if (Serial.available() > 0) {
    char data = Serial.read();
    switch (data) {
      case '0':
        digitalWrite(led, LOW);
        Serial.println("LED IS OFF");
        break;
      case '1':
        digitalWrite(led, HIGH);
        Serial.println("LED IS ON");
        break;
      default:
        break;
    }
  }
}