Arduino library for MFRC522 and other RFID RC522 based modules.
Read and write different types of Radio-Frequency IDentification (RFID) cards on your Arduino using a RC522 based reader connected via the Serial Peripheral Interface (SPI) interface.
The following table shows the typical pin layout used:
| PCD | Arduino | |||
|---|---|---|---|---|
| MFRC522 | Uno | Mega | Nano v3 | |
| Signal | Pin | Pin | Pin | Pin |
| RST/Reset | RST | 9 [1] | 5 [1] | D9 |
| SPI SS | SDA [3] | 10 [2] | 53 [2] | D10 |
| SPI MOSI | MOSI | 11 / ICSP-4 | 52 | D11 |
| SPI MISO | MISO | 12 / ICSP-1 | 51 | D12 |
| SPI SCK | SCK | 13 / ICSP-3 | 50 | D13 |
| [1] | (1, 2) Configurable, typically defined as RST_PIN in sketch/program. |
| [2] | (1, 2) Configurable, typically defined as SS_PIN in sketch/program. |
| [3] | The SDA pin might be labeled SS on some/older MFRC522 boards. |
There are three hardware components involved:
- Micro Controller:
- An Arduino or compatible executing the Sketch using this library.
- Prices vary from USD 7 for clones, to USD 75 for "starter kits" (which might be a good choice if this is your first exposure to Arduino; check if such kit already includes the Arduino, Reader, and some Tags).
- Proximity Coupling Device (PCD):
- The PCD is the actual RFID Reader based on NXP MFRC522 Contactless Reader Integrated Circuit).
- Readers can be found on eBay for around USD 5: search for "rc522".
- You can also find them at several web stores, they are often included in "starter kits"; so check your favourite electronics provider as well.
- Proximity Integrated Circuit Card (PICC):
- The PICC is the RFID Card or Tag using the ISO/IEC 14443A interface, for example Mifare or NTAG203.
- One or two might be included with the Reader or "starter kit" already.
- The micro controller and the reader use SPI for communication.
- The protocol is described in the NXP MFRC522 datasheet.
- See the Pin Layout section for details on connecting the pins.
- The reader and the tags communicate using a 13.56 MHz electromagnetic field.
- The protocol is defined in ISO/IEC 14443-3:2011 Part 3.
- Details are found in chapter 6 "Type A – Initialization and anticollision".
- See http://wg8.de/wg8n1496_17n3613_Ballot_FCD14443-3.pdf for a free version of the final draft (which might be outdated in some areas).
The MFRC522 library was first created in Jan 2012 by Miguel Balboa (from http://circuitito.com) based on code by Dr. Leong (from http://B2CQSHOP.com) for "Arduino RFID module Kit 13.56 Mhz with Tags SPI W and R By COOQRobot".
It was translated into English and rewritten/refactored in the fall of 2013 by Søren Thing Andersen (from http://access.thing.dk).