digital-lock.ino

#include <Keypad.h>
#include <LiquidCrystal.h>

// Initialize the LCD: (RS, EN, D4, D5, D6, D7)
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);

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

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

// Connect keypad rows and columns to Arduino pins
byte rowPins[ROWS] = {9, 8, A3, A2};
byte colPins[COLS] = {A1, A0, 13, 12};

// Create the keypad object
Keypad keypad = Keypad(makeKeymap(keyMap), rowPins, colPins, ROWS, COLS);

// Set your password here
String correctPassword = "1234";
String userInput = "";

void setup() {
  lcd.begin(16, 2); // Set LCD size
  lcd.print("Enter Password:");
  lcd.setCursor(0, 1); // Move to second line
}

void loop() {
  char pressedKey = keypad.getKey();

  if (pressedKey) {
    if (pressedKey == '#') {
      // User submitted the input
      checkPassword();
    }
    else if (pressedKey == '*') {
      // Clear input if * is pressed
      resetInput();
    }
    else {
      // Add character to input
      if (userInput.length() < 16) {
        userInput += pressedKey;
        lcd.print('*'); // Hide input for security
      }
    }
  }
}

void checkPassword() {
  lcd.clear();
  if (userInput == correctPassword) {
    lcd.print("Access Granted");
  } else {
    lcd.print("Access Denied");
  }
  delay(2000);
  resetInput();
}

void resetInput() {
  userInput = "";
  lcd.clear();
  lcd.print("Enter Password:");
  lcd.setCursor(0, 1);
}