OpenDX

An open replacement for DX Light, the Windows app for Robobloq / "QuikLight" USB LED strip controllers (the kind sold as monitor or desk backlights). It runs in Edge or Chrome, talks to the controller directly over USB serial, and does everything DX Light does: static colors, effects, music and screen sync. It adds more effects, PC-audio music and a proper LED layout editor.

Why this exists

DX Light works, but it's a heavy Electron app with cloud and telemetry bits, a clunky UI, and its music mode only listens to the controller's own microphone. The goal was to get rid of it:

1. Find out how DX Light talks to the controller.
2. Build a cleaner app that controls the strip the same way. This repo.
3. Next: write a SignalRGB plugin so the strip syncs with the rest of the RGB setup.

Quick start

1. Install Node.js (only used for a tiny local web server).
2. Double-click app/Start OpenDX.bat. It closes DX Light (which locks the COM port), starts the server on http://localhost:8642 and opens the app in an Edge window.
3. Click Connect and pick the controller. It reconnects automatically after that.
4. Use ⏻ to turn the strip on or off, then pick a mode.

To stop it, close the app window and the minimized "OpenDX server" window. To keep DX Light from coming back, disable it in Task Manager > Startup apps.

What i found (summary)

Full details, with byte layouts, are in DX-Light-protocol.md.

• How it was found: DX Light is an Electron app. Its resources/app.asar was unpacked (npx @electron/asar extract), and .webpack/main/index.js was beautified and read. The protocol lives there in plain JavaScript. The extracted code isn't part of this repo (.gitignore blocks it).
• Device: USB 1A86:FE0C (WCH chip), a plain USB CDC serial port, 115200 baud 8N1. No driver needed, no HID, no encryption.
• Frames: RB command frames ('R' 'B' len seq action payload checksum), plus an SC frame for fast per-LED updates on firmware > 1.0.2. The checksum is the sum of all bytes & 0xFF.
• Colors: 5-byte groups [startLed, R, G, B, endLed], 1-based and inclusive, where 254 means "to the end". A run of same-colored LEDs can be one group.
• Test device: firmware 1.1.2, 63 LEDs, reported by the controller itself (readDeviceInfo).
• Hardware limits: USB only, no Wi-Fi or Bluetooth. Its 3 buttons don't send anything to the PC. The controller's built-in music uses its onboard mic. On a wall charger it just runs its built-in effects.
• Open questions: the maximum frame rate (fast streaming once froze an animation), the full list of built-in effect indexes, and whether the "PC audio levels → controller" command (0x98) works on this model.

How the app works

Everything is in one file, app/index.html, with no build step and no dependencies. serve.js only serves it on 127.0.0.1, because Web Serial needs a secure origin.

Part	Where (search for)	Notes
Settings	DEFAULTS, save()	Saved in the browser's localStorage (key ledctl), not on the controller
Protocol	rbFrame, scFrame, toGroups, ACT	Byte-for-byte checked against frames the device accepted
Device I/O	connect, FILTER	Reads device info on connect, sets the LED count, picks SC or RB transport by firmware
Effects	EFFECTS	17 effects, rendered in JS and streamed to the strip
Music	startMusicSource, MUSIC	Sources: PC audio (screen share + system audio), mic, controller mic, PC audio → controller (experimental)
Screen sync	startScreen, layoutLeds, renderScreen, autoLayout	Captures at 128×72 and averages an edge region per LED. Layout = LEDs per side + start corner + direction
Output	tick, finalize	A Worker timer drives the loop, so it keeps running when minimized. Applies brightness, color order and reverse, then skips unchanged frames (1 s keep-alive)
Hardware tab	setMode("hardware"), ACT.setLedEffect	Raw access to the controller's built-in effects

Status

• Done: protocol decoded and verified, app with all DX Light modes plus extras, launcher.
• Needs testing on the strip: effect smoothness and max FPS, color order, screen-sync layout, Hardware tab effects, and the experimental PC audio → controller music.
• Next: the SignalRGB plugin. It's a serial device 1A86:FE0C: on connect, read readDeviceInfo for the LED count, then send one SC frame per frame using toGroups range compression. Use the same frame rate that works in the app.
• Idea: for Wi-Fi, standalone use and native SignalRGB/WLED support, the strip itself (probably WS2812B) could be wired to a WLED board instead of this controller.

Repo layout

DX-Light-protocol.md        full protocol reference
app/
  index.html                the whole app
  serve.js                  local static server (127.0.0.1:8642)
  Start OpenDX.bat          launcher

Not affiliated with Robobloq. The protocol was worked out for interoperability with hardware I own.