/*
PINOUT:
RC522 MODULE    Uno/Nano
SDA             D10
SCK             D13
MOSI            D11
MISO            D12
IRQ             N/A
GND             GND
RST             D9
3.3V            3.3V
*/

#include <SPI.h>
#include <RFID.h>

#define SDA_DIO 10  // 53 Arduino Mega
#define RESET_DIO 9

RFID RC522(SDA_DIO, RESET_DIO);

String readCode;
String validCode = "25d24d9a2";

byte i;

void setup()
{
  Serial.begin(9600);
  SPI.begin();

  RC522.init();
  Serial.println("Waiting for a card");
  Serial.println();
}

void loop()
{
  if (RC522.isCard())
  {
    RC522.readCardSerial();

    Serial.print("Code: ");

    for (i = 0; i <= 4; i++)
    {
      readCode += String (RC522.serNum[i], HEX);
    }
    Serial.println(readCode);

    if (readCode.equals(validCode) == true) {

      Serial.println("Valid card!");
    }
    else {
      Serial.println("Access denied!");
    }

    Serial.println();

    readCode = "";
    delay(1000);
  }
}