I just received my RC522 RFID reader and made this simple Arduino access control system that uses the reader, a buzzer for the alarm and a relay shield for the security system. The relay can be used ...

For starters, you need a pre-wired NFC RFID module as the key hardware. NFC and RFID projects have become a huge trend, but many modules are pricey for electronics hobbyists and need a complex setup.