///arduino menu 3 Push Buttons Password Lock
const int button[] = {2,3,4};

int ButtonState[] = {0,0,0,0};
int lastButtonState[] = {0,0,0,0};
int password[] = {0,1,2,2};
int level = 0;
int green = 7;
int red = 8;
void setup() {
  pinMode(button[0], INPUT_PULLUP);
  pinMode(button[1], INPUT_PULLUP);
  pinMode(button[2], INPUT_PULLUP);
  pinMode(green, OUTPUT);
  pinMode(red, OUTPUT);
  level = 0;
}

void loop() {
 
 for(int i=0; i<4; i++)
  {
     ButtonState[i] = digitalRead(button[i]);
  }
  for(int i=0; i<4; i++){    
    if(ButtonState[i] != lastButtonState[i]){
      if(ButtonState[i] == 1){
        switch(level){
          case 0: if(i == password[0]) level++;
                  else level=5;
                  break;
          case 1: if(i == password[1]) level++;
                  else level=5;
                  break;
          case 2: if(i == password[2]) level++;
                  else level=5;
                  break;
          case 3: if(i == password[3]) level++;
                  else level=5;
                  break;
                   }
      }
      lastButtonState[i] = ButtonState[i];
    }
  }

 
  if(level==4){
    digitalWrite(green, HIGH);
    delay(2000);
    digitalWrite(green, LOW);
    level=0;
    }

  if(level==5){
    for(int j=0; j<5; j++){
      digitalWrite(red, HIGH);
      delay(50);
      digitalWrite(red, LOW);
      delay(50);
    }
    level=0;
  }
 
    
  delay(20);
}