#include <Servo.h>
#include <SPI.h>
#include <MFRC522.h>

#define SS_PIN 10
#define RST_PIN 9

MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance

Servo lockServo;  // Create Servo instance

void setup() {
  Serial.begin(9600);  // Initialize serial communication
  
  SPI.begin();  // Initialize SPI communication
  mfrc522.PCD_Init();  // Initialize MFRC522 RFID reader
  
  lockServo.attach(6);  // Attach servo to pin 6
  lockServo.write(0);  // Close the lock initially
}

void loop() {
  // Check for RFID card
  if (mfrc522.PICC_IsNewCardPresent() && mfrc522.PICC_ReadCardSerial()) {
    // Read card UID
    String cardUID = "";
    for (byte i = 0; i < mfrc522.uid.size; i++) {
      cardUID.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? "0" : ""));
      cardUID.concat(String(mfrc522.uid.uidByte[i], HEX));
    }
    cardUID.toUpperCase();  // Convert UID to uppercase
    
    // Compare UID with authorized card
    if (cardUID == "04 D2 6C 8D") {
      Serial.println("Access granted!");
      lockServo.write(90);  // Open the lock
      delay(1000);  // Hold the lock open for 1 second
      lockServo.write(0);  // Close the lock
    } else {
      Serial.println("Access denied!");
    }
  }
  
  mfrc522.PICC_HaltA();  // Halt PICC
  mfrc522.PCD_StopCrypto1();  // Stop encryption on PCD
}