We want to show you how to use the popular Arduino to produce a device capable of recognizing passive transponder (TAG). But this is not the usual RFID key, because the system can activate a relay if a recognised TAG is read, but also we took the opportunity to make an application that use cloud-computing. The basic version, which is a simple key relay consists of an Arduino and the RFID shield based on a ID-12 of Innovations: placing a transponder already learned, the relay is activated. The extended version of our project uses an Arduino, the RFID Shield and the Ethernet Shield with which we can access the Internet and stored, using the Google Docs service, the transponder data.
Arduino RFID shield on the Cloud - [Link]