qrcode-scanner 0.0.3

Read QR codes from HID devices

QR Code Scanner

A Python library for reading QR codes from HID (Human Interface Device) scanners. This library treats QR code scanners as keyboard input devices and decodes their scanned data.

Features

• Easy-to-use HID device interface
• Support for multiple keyboard layouts
• Automatic character decoding
• Robust error handling
• Non-blocking read operations

Installation

Install using pip:

pip install qrcode-scanner

Or using Poetry:

poetry add qrcode-scanner

Requirements

• Python 3.10+
• hidapi

Quick Start

from qrcode_scanner import HIDScanner
from qrcode_scanner.exceptions import DeviceConnectionError, DeviceNotFoundError, DeviceReadError

# Replace with your device's vendor ID and product ID
VENDOR_ID = 0x1D82
PRODUCT_ID = 0x5CA0

try:
    # Initialize and connect to the scanner
    scanner = HIDScanner(vendor_id=VENDOR_ID, product_id=PRODUCT_ID)
    scanner.connect()

    print("Connected to device")
    print("Manufacturer:", scanner.device.get_manufacturer_string())
    print("Product:", scanner.device.get_product_string())

    # Start reading QR codes
    while True:
        try:
            print("Listening for scans...")
            scanned_text = scanner.read()  # Blocking read operation
            if scanned_text:
                print("=== SCAN COMPLETE ===")
                print("Scanned text:", scanned_text)
        except DeviceNotFoundError:
            print("Device not found or not connected")
            break
        except (DeviceReadError, DeviceConnectionError) as e:
            print(f"Device error: {e}")
            break

except KeyboardInterrupt:
    print("Program terminated by user")
finally:
    scanner.close()
    print("HID device closed")

Error Handling

The library includes several exception classes to handle different error scenarios:

• DeviceNotFoundError: When the specified device cannot be found
• DeviceConnectionError: When there are issues connecting to the device
• DeviceNotConnectedError: When trying to read from a disconnected device
• DeviceReadError: When reading from the device fails
• UnknownCharacterError: When encountering unknown character codes

Finding Device IDs

To find your device's vendor and product IDs, you can use the devices() function:

from qrcode_scanner import devices

# List all connected HID devices
for device in devices():
    print(f"Vendor ID: 0x{device['vendor_id']:04X}")
    print(f"Product ID: 0x{device['product_id']:04X}")
    print(f"Product Name: {device.get('product_string', 'N/A')}")
    print("---")

License

MIT License

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.