Interfacing RFID tags with the RPZ
Radio frequency identification, or RFID, is a common method of near-field communication. You can teach your Raspberry Pi to understand an RFID board's communication with RFID cards and keyfobs.
Getting ready
There are a few different RFID kits available. I used the Elegoo RC522 included in their kit, which is a fairly typical RFID board. Adafruit also has kits that detect both RFID cards and NFC signals typically used on smartphones, and they always include great instructions. You'll also need a red-and-green LED and a couple of 330-Ohm resistors. Finally, you will need SPI enabled on your Raspberry Pi Zero; if you haven't done that already, refer to Basics of SPI and Setting up the SPI Module in Chapter 5, Getting Your Hands Dirty Using the GPIO Header.
How to do it...
If you completed the previous recipe and have an RTC board connected, you don't have to remove it! The RFID board communicates over SPI, whereas the RTC talks on I2C.
Configure the RFID board...
