Bluetooth Password-Controlled Door Lock

#include <SoftwareSerial.h> // Include the SoftwareSerial library for Bluetooth communication

// Create a SoftwareSerial object for Bluetooth communication on pins 10 (RX) and 11 (TX)
SoftwareSerial rfSerial(10, 11);

// Define the lock pin connected to the door lock mechanism
int lock = 12;

// Declare character arrays for storing the received ID and the expected ID
char id[13];
char id1[4] = "1234"; // Set the password to "1234"

void setup() {
  Serial.begin(9600);        // Initialize the serial communication at 9600 baud rate
  rfSerial.begin(9600);     // Initialize Bluetooth communication at 9600 baud rate
  pinMode(lock, OUTPUT);     // Set the lock pin as an output
  digitalWrite(lock, 1);     // Set the lock pin to HIGH (lock is engaged)
}

void loop() {
  doorlock(); // Continuously check for door lock functionality
}

void doorlock() {
  // Check if data is available from the Bluetooth serial
  if (rfSerial.available() > 0) {
    // Read the incoming bytes into the id array until a null character is found
    rfSerial.readBytesUntil('\0', id, 4);
    id[4] = '\0'; // Add null terminator to the end of the received string

    // Compare the received ID with the predefined ID
    if (strcmp(id, id1) == 0) {
      Serial.println("HELLO ACCESS GRANTED"); // Print access granted message
      digitalWrite(lock, 0); // Unlock the door (set lock pin to LOW)
      delay(3000);           // Keep the door unlocked for 3 seconds
      digitalWrite(lock, 1); // Lock the door again (set lock pin to HIGH)
    } else {
      digitalWrite(lock, 1); // Ensure the door is locked (set lock pin to HIGH)
      Serial.println("PLEASE PROVIDE RIGHT DETAILS ACCESS DENIED"); // Print access denied message
    }
  }
}