Importance and Utility of Digital Door Locks

Digital door locks are becoming increasingly popular due to their convenience, security, and versatility. Unlike traditional locks that require physical keys, digital door locks use electronic mechanisms to grant access. This eliminates the need for carrying or managing multiple keys, as well as the risk of losing them. Additionally, digital door locks can offer advanced features such as remote access control, time-based access restrictions, and integration with other home automation systems.

By implementing a digital door lock using Arduino, we can create a cost-effective and customizable solution for securing doors in various settings. This article will guide you through the process of building a digital door lock using Arduino, providing example codes and a list of components required.

Project: Digital Door Lock

The project aims to create a digital door lock that can be controlled using a keypad and an LCD display. The lock will have a predefined passcode that users can enter to unlock the door. The system will also provide feedback on the LCD display, indicating whether the entered passcode is correct or incorrect.

Functionalities:

1. Keypad input for entering the passcode.
2. LCD display to show feedback messages.
3. Solenoid lock mechanism to physically lock/unlock the door.
4. Predefined passcode for authentication.

List of Components:

1. Arduino Uno - 1x
2. Keypad - 1x
3. LCD display (16x2) - 1x
4. Solenoid lock - 1x
5. Breadboard - 1x
6. Jumper wires - As required

Note: Links for purchasing the components can be found in the Appendix.

Examples:

Example 1: Initializing the Keypad and LCD Display

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

const int ROWS = 4;
const int 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 keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
LiquidCrystal_I2C lcd(0x27, 16, 2);

Example 2: Verifying the Entered Passcode

void verifyPasscode(char passcode[], int passcodeLength) {
  char enteredPasscode[passcodeLength];

  for (int i = 0; i < passcodeLength; i++) {
    enteredPasscode[i] = keypad.waitForKey();
    lcd.print("*");
    delay(200);
  }

  if (strcmp(enteredPasscode, passcode) == 0) {
    lcd.clear();
    lcd.print("Access Granted");
    unlockDoor();
  } else {
    lcd.clear();
    lcd.print("Access Denied");
  }

  delay(2000);
  lcd.clear();
  lcd.print("Enter Passcode:");
}

Example 3: Unlocking the Door

void unlockDoor() {
  // Code to activate the solenoid lock and unlock the door
}

These examples provide a starting point for building a digital door lock using Arduino. You can further enhance the project by adding features such as multiple user passcodes, remote access control, or integrating it with other home automation systems.