ardrino#串口控制led

void setup() {
  pinMode(D6, OUTPUT);
  digitalWrite(D6,HIGH);
  Serial.begin();
}

void loop() {

  String state = Serial.readString();
  if (state == "off") {
    digitalWrite(D6, HIGH);
    Serial.println("we turn off the led.");
  } else if (state == "on") {
    digitalWrite(D6, LOW);
    Serial.println("we turn on the led.");
  }
  delay();
}