#include <Wire.h> 
#include <LiquidCrystal_I2C.h> // Include the library for I2C LCD
#include <Keypad.h>           // Include the library for Keypad

// Define the I2C address for the LCD module
#define I2C_ADDR    0x27  // Adjusted address for your module

// Define the dimensions of the LCD (number of columns and rows)
#define LCD_COLS    16
#define LCD_ROWS    2

// Create an instance of the LiquidCrystal_I2C class
LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLS, LCD_ROWS);

// Define the keypad layout
const byte ROWS = 4; // Four rows
const byte COLS = 4; // Four columns

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

byte colPins[COLS] = {5, 4, 3, 2}; // Connect to the column pinouts of the keypad
byte rowPins[ROWS] = {9, 8, 7, 6}; // Connect to the row pinouts of the keypad

// Create an instance of Keypad
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup() {
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  
  // Print initial message on LCD
  lcd.print("Arduino LCD Keypad");
  
  // Set up serial communication for debugging
  Serial.begin(9600);
}

void loop() {
  // Read keypad
  char key = keypad.getKey();
  
  // If a key is pressed
  if (key) {
    Serial.println(key); // Print the key to serial monitor
    
  char password[] = "1234"; // Change this to your desired password
char enteredPassword[5]; // Array to store entered password (max length + 1 for null terminator)

int passwordIndex = 0; // Index to track current position in enteredPassword array

// Create an instance of Keypad
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup() {
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  
  // Print initial message on LCD
  lcd.print("Enter password:");
  
  // Set up serial communication for debugging
  Serial.begin(9600);
}

void loop() {
  // Read keypad
  char key = keypad.getKey();
  
  // If a key is pressed
  if (key) {
    if (key == '#') { // Check if Enter key is pressed
      // Compare entered password with predefined password
      if (strcmp(enteredPassword, password) == 0) {
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Access granted");
        delay(2000); // Delay to show "Access granted" message
        lcd.clear();
        lcd.print("Welcome!");
        // Add your code to perform actions after successful authentication
      } else {
        lcd.clear();
        lcd.print("Wrong password");
        delay(2000); // Delay to show "Wrong password" message
        lcd.clear();
        lcd.print("Enter password:");
      }
      
      // Reset entered password for next attempt
      memset(enteredPassword, 0, sizeof(enteredPassword));
      passwordIndex = 0;
    } else if (passwordIndex < sizeof(enteredPassword) - 1) { // Check if there's space to store more characters
      // Append pressed key to enteredPassword
      enteredPassword[passwordIndex++] = key;
      lcd.setCursor(passwordIndex - 1, 1);
      lcd.print('*'); // Display '*' on LCD for each entered character
    }
  }
}
  }
}