RFID e arduino MEGA

Estou tentando usar um sensor RFID-RC522 com o arduino MEGA, já peguei vários códigos exemplo e bibliotecas diferentes, mas o sensor não retorna valor, como se não estivesse lendo o cartão, já até mesmo troquei o sensor rfid, mas não deu em nada.

/*
* MFRC522 - Library to use ARDUINO RFID MODULE KIT 13.56 MHZ WITH TAGS SPI W AND R BY COOQROBOT.
* The library file MFRC522.h has a wealth of useful info. Please read it.
* The functions are documented in MFRC522.cpp.
*
* Based on code Dr.Leong   ( WWW.B2CQSHOP.COM )
* Created by Miguel Balboa (circuitito.com), Jan, 2012.
* Rewritten by Søren Thing Andersen (access.thing.dk), fall of 2013 (Translation to English, refactored, comments, anti collision, cascade levels.)
* Released into the public domain.
*
* Sample program showing how to read data from a PICC using a MFRC522 reader on the Arduino SPI interface.
*----------------------------------------------------------------------------- empty_skull
* Aggiunti pin per arduino Mega
* add pin configuration for arduino mega
* http://mac86project.altervista.org/
----------------------------------------------------------------------------- Nicola Coppola
* Pin layout should be as follows:
* Signal     Pin              Pin               Pin
*            Arduino Uno      Arduino Mega      MFRC522 board
* ------------------------------------------------------------
* Reset      9                49                 RST
* SPI SS     10               53                SDA
* SPI MOSI   11               51                MOSI
* SPI MISO   12               50                MISO
* SPI SCK    13               52                SCK
*
* The reader can be found on eBay for around 5 dollars. Search for "mf-rc522" on ebay.com.
*/

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

#define SS_PIN 53
#define RST_PIN 48
MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance.

void setup() {
  Serial.begin(9600); // Initialize serial communications with the PC
  SPI.begin();      // Init SPI bus
  mfrc522.PCD_Init(); // Init MFRC522 card
  Serial.println("Scan PICC to see UID and type...");
}

void loop() {
  // Look for new cards
  if ( ! mfrc522.PICC_IsNewCardPresent()) {
    return;
  }

  // Select one of the cards
  if ( ! mfrc522.PICC_ReadCardSerial()) {
    return;
  }

  // Dump debug info about the card. PICC_HaltA() is automatically called.
  mfrc522.PICC_DumpToSerial(&(mfrc522.uid));
}