void setup() {
  pinMode(3, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  if (Serial.available() > 0) {
    int input = Serial.read();
    if (input == '1') {
      digitalWrite(3, HIGH);
      String output = "Encendido @";
      output += millis();
      output += "ms";
      Serial.println(output); 
    } else {
      digitalWrite(3, LOW);
      String output = "Apagado @";
      output += millis();
      output += "ms";
      Serial.println(output); 
    }
  }
}