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

LiquidCrystal_I2C lcd(0x27, 20, 4);

const byte ROWS = 4;    
const byte COLS = 4;    

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

byte rowPins[ROWS] = { 9, 8, 7, 6 }; 
byte colPins[COLS] = { 5, 4, 3, 2 };

Keypad customKeypad = Keypad(makeKeymap(Keys), rowPins, colPins, ROWS, COLS);

char customKey;         
int number = 0;         
int password = 1415;   
int buzzer = 10; // Define buzzer pin

void setup() {
  lcd.init();              
  lcd.setBacklight(HIGH);  
  pinMode(buzzer, OUTPUT);
}

void loop() {
  lcd.setCursor(0, 0);
  lcd.print("Welcome master");      

  customKey = customKeypad.getKey();    

  if (customKey) {
    if (customKey >= '0' && customKey <= '9') {
      number = number * 10 + (customKey - '0');
      lcd.setCursor(0, 1);
      lcd.print(number);
    }

    if (customKey == '#') {
      if (number == password) {           
        lcd.setCursor(0, 1);
        lcd.print("Access Accepted"); 
        number = 0;
        delay(800);
        lcd.clear();
        playMelody(); // Play melody on correct password
      } else {                             
        lcd.setCursor(0, 1);
        lcd.print("Invalid Password");  
        number = 0;
        delay(800);
        lcd.clear();
      }
    }

    if (customKey == '*') {
      number = 0;
      lcd.clear();
    }
  }
}

void playMelody() {
  int melody[] = {262, 294, 330, 349, 392}; // Example notes (C4 to G4)
  int noteDuration = 500; // Duration for each note

  for (int i = 0; i < 5; i++) {
    tone(buzzer, melody[i], noteDuration);
    delay(noteDuration);
    noTone(buzzer);
  }
}