How can I add NFC function to my home door for just 10 dollars？

				
					#include <Wire.h>
#include <Adafruit_PN532.h>
#include <Servo.h>

// Define the pins for the PN532 module (using I2C)
#define PN532_IRQ   (2)
#define PN532_RESET (3)  // Not used in this I2C configuration

Adafruit_PN532 nfc(PN532_IRQ, PN532_RESET);
Servo myServo;

void setup(void) {
  Serial.begin(115200);
  while (!Serial) {
    delay(10); // Wait for serial port to connect.
  }

  myServo.attach(9);  // Attaches the servo on pin 9
  myServo.write(0);   // Start the servo at 0 degrees

  nfc.begin();

  uint32_t versiondata = nfc.getFirmwareVersion();
  if (!versiondata) {
    Serial.print("Didn't find PN53x board");
    while (1); // halt
  }

  // Got ok data, print it out!
  Serial.print("Found chip PN5"); Serial.println((versiondata >> 24) & 0xFF, HEX);
  Serial.print("Firmware ver. "); Serial.print((versiondata >> 16) & 0xFF, DEC);
  Serial.print('.'); Serial.println((versiondata >> 8) & 0xFF, DEC);

  // Set the max number of retry attempts to read from a card
  // This helps prevent the program from getting stuck trying to read a card that is moved away quickly
  nfc.setPassiveActivationRetries(0xFF);

  // configure board to read RFID tags
  nfc.SAMConfig();

  Serial.println("Waiting for an ISO14443A Card ...");
}

void loop(void) {
  boolean success;
  uint8_t uid[] = { 0, 0, 0, 0, 0, 0, 0 };  // Buffer to store the returned UID
  uint8_t uidLength;                        // Length of the UID (4 or 7 bytes depending on ISO14443A card type)

  // Wait for an ISO14443A type cards (Mifare, etc.).  When one is found
  // 'uid' will be populated with the UID, and uidLength will indicate
  // if the uid is 4 bytes (Mifare Classic) or 7 bytes (Mifare Ultralight)
  success = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength);

  if (success) {
    Serial.println("Found a card!");
    Serial.print("UID Length: "); Serial.print(uidLength, DEC); Serial.println(" bytes");
    Serial.print("UID Value: ");
    nfc.PrintHex(uid, uidLength);
    Serial.println("");

    // Rotate the servo
    myServo.write(90);
    delay(1000); // Wait a second for the servo to reach the position
  } else {
    // If no card is found, you can have the servo return to the original position
    myServo.write(0);
  }

  // A short delay is good practice to prevent spamming the NFC reader
  delay(100);
}