int ledPin = 13; // Built-in LED or external LED on pin 13

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);
  Serial.println("Type 1 to ON, 0 to OFF");
}

void loop() {
  if (Serial.available() > 0) {
    char input = Serial.read();
    if (input == '1') {
      digitalWrite(ledPin, HIGH);
      Serial.println("LED ON");
    } else if (input == '0') {
      digitalWrite(ledPin, LOW);
      Serial.println("LED OFF");
    }
  }
}