const int OUT = LED_BUILTIN; // Ausgangs pin
const int TIME_ON = 5 * 60;   //länge des Pulses in Sekunden
const int TIME_OFF = 30 * 60; //zeit zwischen den Pulsen in Sekunden 
const int T_ON = TIME_ON * 1000;
const int T_OFF = TIME_OFF * 1000;
void setup() {
  // put your setup code here, to run once:
  pinMode(OUT, OUTPUT);
  Serial.begin(9600);
  Serial.print("Länge des Pulses: ");
  Serial.print(TIME_ON);
  Serial.println(" Sekunden.");

  Serial.print("Zeit zwischen den Pulsen: ");
  Serial.print(TIME_OFF);
  Serial.println(" Sekunden.");
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(OUT, HIGH);
  delay(T_ON);
  digitalWrite(OUT, LOW);
  delay(T_OFF);
}