#include <Keypad.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2); 

#define BARIS 4
#define KOLOM 4

char keys[BARIS][KOLOM] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins[BARIS] = {14, 12, 19, 18};
byte colPins[KOLOM] = {5, 4, 2, 15};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, BARIS, KOLOM);

char pressedKey;
int number = 0;
int password = 2109;

void setup() {
  Serial.begin(115200);
  lcd.init();
  lcd.backlight();
  // lcd.setCursor(0,0);
}

void loop() {
  lcd.setCursor(0,0);
  lcd.print("Input Password: ");

  pressedKey = keypad.getKey();

  switch (pressedKey) {
    case '0' ... '9':
      lcd.setCursor(0,1);
      number = number * 10 + (pressedKey - '0');
      if (number >= 10000) {
        lcd.print("4 chars only.");
        delay(2000);
        lcd.clear();
      } else
      lcd.print(number);
      break;

    case '*':
      number = 0;
      lcd.clear();
      break;

    case '#':
      lcd.setCursor(0,1);
      if (number == password)
        lcd.print("Access accepted.");
      else
        lcd.print("Access denied.");
      
      delay(2000);
      number = 0;
      lcd.clear();
      break;
  }
}