#define BUTTON   2
#define LED_RED    5
#define LED_YELLOW 6
#define LED_GREEN  7

void setup() {
  Serial.begin(9600); // serielle Schnittstelle vorbereiten
  pinMode ( BUTTON, INPUT );
  pinMode ( LED_RED, OUTPUT );
  pinMode ( LED_YELLOW, OUTPUT );
  pinMode ( LED_GREEN, OUTPUT );
}

void loop() {
  digitalWrite ( LED_GREEN, HIGH );
  if ( digitalRead ( BUTTON ) == HIGH ) {
    digitalWrite ( LED_RED, HIGH );
  }
  delay ( 300 );
  digitalWrite ( LED_GREEN, LOW );
  digitalWrite ( LED_RED, LOW );
  delay ( 300 );
}