pyrc522 provides a simple interface for controlling an SPI RFID module "RC522" using Raspberry Pi.
Based on MFRC522-python and pi-rc522.
Install using pip:
pip install pyrc522
Or get source code from Github:
git clone https://github.com/fladi/pyrc522.git
cd pyrc522
python setup.py install
You'll also need to install the periphery library.
MIFARE datasheet can be useful.
Classic 1K MIFARE tag has 16 sectors, each contains 4 blocks. Each block has 16 bytes. All this stuff is indexed - you must count from zero. The library uses "block addresses", which are positions of blocks - so block address 5 is second block of second sector, thus it's block 1 of sector 1 (indexes). Block addresses 0, 1, 2, 3 are from the first sector - sector 0. Block addresses 4, 5, 6, 7 are from the second sector - sector 1, and so on. You should not write to first block - S0B0, because it contains manufacturer data. Each sector has it's sector trailer, which is located at it's last block - block 3. This block contains keys and access bits for corresponding sector. For more info, look at page 10 of the datasheet. You can use this useful utility to calculate access bits.
Connecting RC522 module to SPI is pretty easy. You can use this neat website for reference.
| Board pin name | Board pin | Physical RPi pin | RPi pin name |
|---|---|---|---|
| SDA | 1 | 24 | GPIO8, CE0 |
| SCK | 2 | 23 | GPIO11, SCKL |
| MOSI | 3 | 19 | GPIO10, MOSI |
| MISO | 4 | 21 | GPIO9, MISO |
| IRQ | 5 | 18 | GPIO24 |
| GND | 6 | 6, 9, 20, 25 | Ground |
| RST | 7 | 22 | GPIO25 |
| 3.3V | 8 | 1,17 | 3V3 |
You can also connect the SDA pin to CE1 (GPIO7, pin #26) and call the RFID constructor with bus=0, device=1 and you can connect RST pin to any other free GPIO pin and call the constructor with pin_rst=BOARD numbering pin. Furthermore, the IRQ pin is configurable by passing pin_irq=BOARD numbering pin.
NOTE: For RPi A+/B+/2/3 with 40 pin connector, SPI1/2 is available on top of SPI0. Kernel 4.4.x or higher and dtoverlay configuration is required. For SPI1/2, pin_ce=BOARD numbering pin is required.
You may change BOARD pinout to BCM py passing pin_mode=RPi.GPIO.BCM. Please note, that you then have to define all pins (irq+rst, ce if neccessary). Otherwise they would default to perhaps wrong pins (rst to pin 15/GPIO22, irq to pin 12/GPIO18).
The library provides a single class - RFID. You basically want to start with while True loop and "poll" the tag state. That's done using request method. Most of the methods return error state, which is simple boolean - True is error, False is not error. The request method returns True if tag is not present. If request is successful, you should call anticoll method. It runs anti-collision algorithms and returns used tag UID, which you'll use for select_tag method. Now you can do whatever you want. Important methods are documented.
from pyrc522 import RFID
rdr = RFID()
while True:
rdr.wait_for_tag()
(error, tag_type) = rdr.request()
if not error:
print("Tag detected")
(error, uid) = rdr.anticoll()
if not error:
print("UID: " + str(uid))
# Select Tag is required before Auth
if not rdr.select_tag(uid):
# Auth for block 10 (block 2 of sector 2) using default shipping key A
if not rdr.card_auth(rdr.auth_a, 10, [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF], uid):
# This will print something like (False, [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])
print("Reading block 10: " + str(rdr.read(10)))
# Always stop crypto1 when done working
rdr.stop_crypto()
# Calls GPIO cleanup
rdr.cleanup()