webbluetooth-drivers

Java APIs for various BLE devices implemented using Vaadin + Web Bluetooth API. Each device driver is a Vaadin component that handles the Bluetooth connection and device-specific protocol, allowing Java developers to interact with BLE hardware directly from server-side code.

Modules

ble-label-common

Shared base module for BLE label printers. Contains:

• LabelImage — base class for label rendering with QR code generation (ZXing), text drawing, trimming, and PNG export. Extends Vaadin's Image component for in-browser preview.
• LabelPrinter — common interface implemented by all printer drivers: requestConnection(), print(BufferedImage), disconnect(), isConnected(), addConnectionListener().
• UnifiedLabelPrinter — a single component that supports multiple printer types through one Bluetooth pairing dialog. Auto-detects the connected printer (Phomemo or Dymo) and uses the correct protocol. Reports the detected PrinterType so the app can adjust label format accordingly.

phomemo-driver

Driver for Phomemo thermal label printers. Tested on Phomemo M110 (Clas Ohlson branded version). Converts images to the M110 raster protocol and sends via BLE in 128-byte chunks. Includes LabelImage subclass with 203 DPI defaults (40mm x 30mm).

dymo-letratag-200b

Driver for the Dymo LetraTag 200B Bluetooth label printer. Implements the LetraTag protocol with 9-byte header, checksum, 500-byte chunked transfer, and chunk index 27 skip (vendor quirk). Includes LetraTagLabelImage with fixed 32-pixel height and 2x horizontal stretching to match the device's print characteristics.

wozinsky-wik-10

Driver for the Wozinsky WIK-10 BLE kitchen scale (Chipsea CST34XX chipset). Parses weight notifications from the scale's GATT service and reports weight in grams with stable/measuring status. Includes a built-in UI component with weight display and connect/disconnect button.

label-printer-demo

Demo application combining the printer drivers and scale into a product labeling workflow. Features:

• Hierarchical product selector (category → species → cut) optimized for tablet use
• Unified printer connection supporting both Phomemo and Dymo printers
• Wozinsky scale integration with auto-print on stable weight
• Label preview with product name, weight, and date

Run with mvn spring-boot:test-run from the label-printer-demo directory.

rpi-letra-example

An example of an alternative angle for using Bluetooth device like a label printer than via WebBluetooth. Uses partly the same Java code as the WebBluetooth driver for dymo-letratag-200b, but instead of using via browser there is a tiny Raspberry Pi software that turns your Raspberry Pi into a "print server" that can then be connected to a server "anywhere in the interwebs".

The web server part of the example lives in the WWCD demo.

Note that the example is trivial PoC. For real world usage of such pattern, you'll probably want to setup some sort of security and in the UI let users choose to which printer they want their tags/receipts/whatever to be printed (demo now prints to all connected print servers).

Requirements

• Java 21+
• Chrome or Edge with Web Bluetooth support
• HTTPS (required by Web Bluetooth API; dev server provides this)
• For auto-reconnect: enable chrome://flags/#enable-web-bluetooth-new-permissions-backend