RFID – radio frequency identification. Some of us have already used these things, and they have become part of everyday life. For example, with electronic vehicle tolling, door access control, public transport fare systems and so on. It sounds complex – but isn’t.
To explain RFID for the layperson, we can use a key and lock analogy. Instead of the key having a unique pattern, RFID keys hold a series of unique numbers which are read by the lock. It is up to our Arduino sketch to determine what happens when the number is read by the lock. The key is the tag, card or other small device we carry around or have in our vehicles. We will be using a passive key, which is an integrated circuit and a small aerial. This uses power from a magnetic field associated with the lock. Some key or tag examples are shown in the image above.
Step 1: Getting started
These readers are quite small and inexpensive – however the catch is that the loop aerial is somewhat fragile. If you need something much sturdier, consider the ID20 tags used in the other RFID tutorial.