turn LED on/off via serial-monitor

turn LED on|off via serial-monitor

String inputString = "";
String copy = "";
bool stringComplete = false;

void setup() {
  Serial.begin(9600);
  inputString.reserve(200);
  copy.reserve(200);
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  if (stringComplete) {
    copy = inputString;
    copy.trim();
    copy.toLowerCase();
    if (copy.equals("off")) {
      digitalWrite(LED_BUILTIN, LOW);
    } else if (copy.equals("on")) {
      digitalWrite(LED_BUILTIN, HIGH);
    } else {
      Serial.println(inputString);
    }
    inputString = "";
    copy = inputString;

    stringComplete = false;
  }
}

void serialEvent() {
  while (Serial.available()) {
    char inChar = (char)Serial.read();
    if (inChar == '\n') {
      stringComplete = true;
    } else {
      inputString += inChar;
    }
  }
}