int LED = 1;

String data;
char d1;

void setup() {
  pinMode(LED, OUTPUT);
  Serial.begin(9600);  // Initialize serial communication
}

void loop() {
  if (Serial.available()) {
    data = Serial.readString();
    d1 = data.charAt(0);
    if (d1 == 'n') {
      digitalWrite(LED, HIGH);
    } else {
      digitalWrite(LED, LOW);
    }
  }
}