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

// Define the pins
#define SS_PIN 22   // SDA Pin
#define RST_PIN 5   // RST Pin

// Create an instance of the MFRC522 class
MFRC522 rfid(SS_PIN, RST_PIN);

void setup() {
  Serial.begin(115200);
  SPI.begin(); // Initialize SPI bus
  rfid.PCD_Init(); // Initialize MFRC522
  
  Serial.println("Place your card/tag near the RFID reader...");
}

void loop() {
  // Look for new RFID cards
  if ( ! rfid.PICC_IsNewCardPresent()) {
    return;
  }

  // Select one of the cards
  if ( ! rfid.PICC_ReadCardSerial()) {
    return;
  }

  // Print the UID of the card
  Serial.print("UID tag: ");
  String content = "";
  for (byte i = 0; i < rfid.uid.size; i++) {
    Serial.print(rfid.uid.uidByte[i] < 0x10 ? " 0" : " ");
    Serial.print(rfid.uid.uidByte[i], HEX);
    content.concat(String(rfid.uid.uidByte[i] < 0x10 ? " 0" : " "));
    content.concat(String(rfid.uid.uidByte[i], HEX));
  }
  Serial.println();

  // Halt PICC
  rfid.PICC_HaltA();
}