razrc522

Modern Python library for RC522 RFID reader - updated for current Python and kernel versions 6+

About

This is a modernized repository of the original pi-rc522 library with significant improvements:

• Modern GPIO handling - Rewritten to use current gpiozero and lgpio libraries instead of deprecated RPi.GPIO
• Simplified API - Easy-to-use EasyRFID wrapper class for common operations
• Multiple UID formats - Support for various UID output modes (HEX, decimal, binary, base64, etc.)
• IRQ support - Optimized for RC522 modules with interrupt pin for efficient tag detection
• Python 3.7+ compatibility - Updated for modern Python versions
• Kernel 6+ support - Works with latest Raspberry Pi OS releases and Compute Module 4/5
• Better error handling - Simple boolean returns instead of complex error tuples like original's (error, data, length)
• Production ready - Designed for real-world applications, not just prototypes

Hardware Compatibility

This library is specifically designed for RC522 RFID modules with IRQ pin support.

Recommended Hardware

Compute Module 4/5 Production Base Board with RFID - Professional development board specifically designed for RFID applications:

Hardware Features:

• Dedicated SPI RFID connector - TE Connectivity 3-640621-8 with all required lines (MISO, MOSI, SCK, SDA, IRQ, RST, 3V3, GND)
• No wiring required - Direct plug-and-play compatibility with RC522 modules
• Production-grade components - 100Mb/s Ethernet, USB-C power, HDMI output, RTC with battery backup
• Compact design - 64.5×92.6×15.2mm, perfect for enclosure mounting
• Built-in signaling - Buzzer and programmable GPIO for status indication

Software Integration:

• Perfect pin mapping - Default configuration matches this library exactly
• Sample applications included - REST API software for immediate deployment
• CM4/5 eMMC support - Industrial-grade storage for production applications

Ideal Use Cases:

• Access control and time registration systems
• IoT devices with RFID authentication
• Industrial terminals and kiosks
• Prototype-to-production development

While this library works with any RC522 setup, the above board eliminates wiring complexity and provides a complete hardware platform for professional RFID applications.

Default Pin Configuration

• RST: GPIO 22
• CE: GPIO 0 (CE0)
• IRQ: GPIO 18
• SPI: Default SPI0 (MOSI=GPIO 10, MISO=GPIO 9, SCLK=GPIO 11)

Installation

pip install razrc522

Quick Start

Simple UID Reading

from razrc522.rfid import RFID
from razrc522.easyrfid import EasyRFID, EasyRFIDUIDMode

# Initialize reader
reader = RFID()
easy_rfid = EasyRFID(reader, mode=EasyRFIDUIDMode.HEX)

# Read UID in different formats
while True:
    uid = easy_rfid.wait_and_read_uid()
    print(f"Card UID: {uid}")

Reading and Writing Data

from razrc522.rfid import RFID
from razrc522.easyrfid import EasyRFID, EasyRFIDUIDMode, EasyRFIDAuth

reader = RFID(antenna_gain=7)
easy_rfid = EasyRFID(reader, mode=EasyRFIDUIDMode.HEX)

while True:
    # Wait for card and select it
    uid, raw_uid = easy_rfid.wait_and_select()
    print(f"Selected card: {uid}")
    
    # Authorize with default MIFARE key
    block = 8
    if easy_rfid.authorize(EasyRFIDAuth.AuthB, [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF], raw_uid, block):
        # Read block
        data = easy_rfid.read_block(block)
        if data:
            text = easy_rfid.bytes_to_uid(data, EasyRFIDUIDMode.STRING)
            print(f"Block {block} contains: {text}")
            
        # Write data (16 bytes required)
        message = b"Hello RFID World!"[:16].ljust(16, b'\x00')
        if easy_rfid.write_block(block, message):
            print("Write successful!")

UID Output Modes

The EasyRFIDUIDMode enum supports various output formats:

• HEX - Hexadecimal string (e.g., "a1b2c3d4")
• HEX_BACKWARD - Reversed hexadecimal
• DECIMAL - Decimal string
• BINARY - Binary string
• BASE64 - Base64 encoded
• INT_LIST - List of integers (default)
• STRING - ASCII string representation
• RAW - Raw bytes object

# Switch between modes dynamically
easy_rfid.set_new_mode(EasyRFIDUIDMode.DECIMAL)
uid_decimal = easy_rfid.wait_and_read_uid()

# Or convert existing data
hex_uid = easy_rfid.bytes_to_uid([161, 178, 195, 212], EasyRFIDUIDMode.HEX)

Advanced Configuration

Custom Pin Setup

reader = RFID(
    bus=0,              # SPI bus
    device=0,           # SPI device
    speed=1000000,      # SPI speed
    pin_rst=22,         # Reset pin
    pin_ce=0,           # Chip enable pin
    pin_irq=18,         # Interrupt pin
    antenna_gain=7,     # Antenna gain (0-7)
    logger=None         # Custom logger
)

Antenna Gain Settings

The antenna gain affects the reading range:

• 0: 18 dB
• 1: 23 dB
• 2: 18 dB
• 3: 23 dB
• 4: 33 dB (default)
• 5: 38 dB
• 6: 43 dB
• 7: 48 dB (maximum range)

Examples

See the examples/ directory for complete working examples:

• read_uid_modes.py - Demonstrates all UID output modes
• read_full_0.py - Reading card data with authentication
• write.py - Writing data to cards with random content

Requirements

• Python 3.7+
• Raspberry Pi with SPI enabled
• RC522 RFID module with IRQ pin connected
• Linux kernel 6+ (for modern GPIO support)

Dependencies

• gpiozero==2.0.1 - Modern GPIO control
• spidev==3.7 - SPI communication
• lgpio==0.2.2.0 - Low-level GPIO access

License

MIT License - see LICENSE file for details.

Contributing

Issues and pull requests welcome! This library aims to provide a simple, modern interface for RC522 RFID operations on Raspberry Pi.

Credits

• Original pi-rc522 by Ondřej Ondryáš
• Modernized and extended by Adam Raźniewski

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For more hardware solutions and Raspberry Pi accessories, visit razniewski.eu