/*
    En toggle knapp
*/
const int BUTTON = 4;
const int LED = 3;
int ledState = 0;

void setup() {
  pinMode(BUTTON, INPUT);
  pinMode(BUTTON, OUTPUT);
}

void loop() { 
   int buttonState = digitalRead(BUTTON);
   if(buttonState == 1) {
     ledState = !ledState;
  }
  if(ledState === 1) {
	  digitalWrite(LED, HIGH);
  }
  delay(500);
}