With this system his RFID-embedded ID card is read by an RFID evaluation shield connected to an Arduino Uno board. His RFID code is approved and a servo opens the door.

Instructables user talk2bruce created the Arduino Internet Gizmo, a card reader that takes you to your favorite websites with a touch of an RFID tag.

After you've assembled the rather complex contraption, you affix color-coded RFID tags to your gadgets, before registering them with the Arduino-based host.