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

#define SS_PIN  9
#define RST_PIN 10

MFRC522 rfid(SS_PIN, RST_PIN);
 String content= "";

void setup() {
  Serial.begin(115200);
  SPI.begin();
  rfid.PCD_Init();
  Serial.println("MFRC522 Hazir...");
  Serial.println("Karti okutun...");
}

void loop() {
  if (!rfid.PICC_IsNewCardPresent()) {
    return;
  }

  if (!rfid.PICC_ReadCardSerial()) {
    return;
  }

  Serial.print("Kart UID:");
  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();
  
  content.toUpperCase();
  
  if (content.substring(1) == "01 02 03 04") 
  {
    Serial.println("Erisim saglandi...");
  }
  else 
  {
    Serial.println("!! Erisim Reddedildi !!");
  }

  rfid.PICC_HaltA();
  delay(1000);
}