/*
  Forum: https://forum.arduino.cc/t/einfache-if-schleife/1176612
  Wokwi: https://wokwi.com/projects/378131879225047041

*/

#include <Servo.h> 

int servoPin = 9;
const int button_pin = 13;
 
Servo servo;  
 
int closed = 90;   // servo position in degrees 
int open = 0;
int oldState = 1;
int state = 1;
int button;
 

void setup() 
{ 
  Serial.begin(9600);
  servo.attach(servoPin); 
  pinMode(button_pin, INPUT_PULLUP);
  servo.write(open);
} 
 
 
void loop() 
{ 
  if (buttonJustDown()) {
    state = !state;
  }
  if (state != oldState){
    oldState = state;
    switch (state){
      case 0: servo.write(closed);
          break; 
      case 1: servo.write(open);
          break;
    }
    
  }
}

boolean buttonJustDown(){
  static unsigned long lastChange = 0;
  static byte buttonState = HIGH;
  static byte lastState = HIGH;
  boolean justDown = false;
  byte actState = digitalRead(button_pin);
  if (actState != lastState) {
    lastChange = millis(); 
    lastState = actState;
  }
  if (actState != buttonState && millis()-lastChange > 30){
    buttonState = actState;
    if (buttonState == LOW) {
      justDown = true;
    } 
  }
  return justDown;
}