Add serial barcode scanner

[alexjamesgodfrey]

Summary

Adds a generic serial barcode scanner implementation.

This supports barcode scanners configured as RS-232 or USB virtual COM devices, which I use to read WONE NICE scanners when configured to USB virtual COM. The implementation uses PLR's existing pylabrobot.io.Serial wrapper and exposes the existing BarcodeScanner capability through a SerialBarcodeScanner device.

WONE NICE usage

For the WONE NICE wireless scanner, I had to scan these setup barcodes from the manual so that it would stream barcodes via the com port:

1. Restore defaults
2. Match
3. Instant upload Mode
4. USB virtual COM
5. Add Carriage Return or CR
6. Duplicate detection-OFF
7. Continuous Mode or Keys Trigger

After switching to USB virtual COM, unplug/replug the USB receiver. It should appear as a serial port, for example:

• Windows: COM5
• Linux: /dev/ttyACM0 or /dev/ttyUSB0

Example:

from pylabrobot.capabilities.barcode_scanning import SerialBarcodeScanner

scanner = SerialBarcodeScanner(
  port="COM5",
  baudrate=115200,
  symbology="Code 128 (Subset B and C)",
)

await scanner.setup()

barcode = await scanner.barcode_scanning.scan(read_time=5)
if barcode is None:
  print("No barcode read.")
else:
  print(barcode.data)

await scanner.stop()

If using VID/PID discovery instead of an explicit port:

scanner = SerialBarcodeScanner(
  vid=0x0C2E,
  pid=0x0900,
  baudrate=115200,
)

Observed WONE NICE behavior: the scanner emits barcode data when it performs a decode event. With a barcode sitting statically in front of the scanner, it may not repeatedly emit the same barcode. Moving the barcode out of and back into the scan field creates a new decode event. This is scanner firmware behavior, not PLR behavior.

What's included

• SerialBarcodeScannerDriver

  • Owns a PLR Serial connection.
  • Supports explicit port or VID/PID serial port resolution.
  • Reads barcode lines terminated by CR and/or LF.

• SerialBarcodeScannerBackend

  • Implements BarcodeScannerBackend.
  • Returns Barcode on successful read.
  • Returns None when the read window elapses without a barcode.
  • Supports optional trigger_command and untrigger_command for scanners with documented serial trigger commands.

• SerialBarcodeScanner

  • v1b1 Device wiring driver + barcode scanning capability.

• Docs/API exports for the barcode scanning capability.

• 11 unit tests covering line reads, timeout behavior, trigger-command behavior, validation, and device lifecycle wiring.

Notes

I intentionally did not add WONE NICE-specific code. The WONE NICE works as a generic USB virtual COM barcode scanner, and the manuals I found do not document a host-side serial trigger protocol.

No native binaries, package data, HID dependencies, or Windows-specific code are added.

Validation

• python3 -m unittest pylabrobot.capabilities.barcode_scanning.serial_tests
• uv run --extra test pytest pylabrobot/capabilities/barcode_scanning/serial_tests.py
• uvx ruff check pylabrobot/capabilities/barcode_scanning/serial.py pylabrobot/capabilities/barcode_scanning/serial_tests.py
• uvx mypy --follow-imports=skip pylabrobot/capabilities/barcode_scanning/serial.py pylabrobot/capabilities/barcode_scanning/serial_tests.py

Hardware observed on WONE NICE receiver:

• COM5
• USB Serial Device
• VID/PID: 0C2E:0900
• Serial: YUNEW
• Barcode output observed as CR-terminated serial data, e.g. 2263408636\r