FallenLight is a lightweight Windows 10/11 tray app that turns a Robobloq USB monitor light strip into a smooth, low-latency Ambilight / screen sync — without the official DX Light / Robobloq SyncLight app, without OpenRGB or SignalRGB plugins, and without making Windows stutter on high refresh rate monitors (tested at 3440×1440 @ 165 Hz, HDR on).
If the official app makes your desktop feel choppy, or your strip shows up in SignalRGB as "ROBOBLOQ USBHID – Plugin: None", this is for you.
➡️ Latest release → download FallenLight-vX.Y.zip, unzip anywhere you can write to (e.g. Documents), run FallenLight.exe.
- Nothing to install — the .NET runtime is bundled.
- First launch: Windows SmartScreen may say "Windows protected your PC" (the app isn't code-signed). Click More info → Run anyway.
- Close DX Light / SyncLight, OpenRGB and SignalRGB first, otherwise they fight over the strip.
| Controller | ROBOBLOQ "USBHID", USB VID:PID 1a86:fe07 (HID, vendor page 0xFF00, 64-byte reports) |
| Strips | Robobloq / DX Light / SyncLight USB-powered monitor backlight strips. Tested: 34" kit — 75 LEDs = 17 left + 41 top + 17 right; 32" kit — 78 LEDs = 21 + 36 + 21 (firmware 1.9.4) |
| Other sizes | Should work — set LEDs per side in Settings and use the Test button |
| OS | Windows 10 / 11, 64-bit |
The controller is detected automatically; size, LED count and firmware version are read from the device.
- Efficient capture — DXGI Desktop Duplication with GPU downscaling (mipmaps). Only a ~215×90 image reaches the CPU: ~0.3–0.6 ms per frame, ~1–3 % of one CPU core at 30 fps.
- HDR aware — captures the real 16-bit (FP16 scRGB) desktop and normalizes it to your Windows SDR content brightness, so HDR games don't wash out to white.
- Color controls — gamma (default 2.2), black threshold, saturation, smoothing, brightness, edge sampling depth, capture FPS.
- Strip layout — LEDs per side + start corner (bottom-left clockwise or bottom-right counter-clockwise), with a 5-second Test pattern (left red, top green, right blue, first LEDs white).
- Turns the strip off on shutdown/restart, sleep/hibernate and when the monitor goes to standby (the controller is powered by the monitor's USB and would otherwise keep its last color).
- Auto-updates — Check for updates downloads, verifies (SHA-256) and installs new versions, then restarts.
- Multiple strips / multiple monitors — each strip is detected automatically and has its own mode, monitor, LED layout and colors; Identify makes a strip blink.
- Light effects besides Ambilight — static color, breathing, rainbow wave, rainbow cycle, aurora (3 custom colors); adjustable speed, strips stay in sync.
- English / Romanian interface.
- Tray app, start with Windows, multi-monitor selection, live stats.
The strip uses a proprietary HID protocol: RB frames (52 42 len id cmd … sum) for simple commands and SC frames (53 43 lenHi lenLo id cmd … sum) split into 64-byte reports for per-LED data. Screen sync is command 0x80 with [start, R, G, B, end] tuples (1-based LED indices); 0x82 returns device info. Checksums are a byte sum. Credit to the OpenRGB project for the original reverse engineering — FallenLight is an independent implementation (no OpenRGB code is used); the protocol details were also verified on real hardware.
- Vortice.Windows (Direct3D11, DXGI bindings) — MIT License
- .NET Runtime / Windows Forms — MIT License
Robobloq, SyncLight, DX Light, monitor light strip, monitor backlight, screen sync, ambilight, ambient light, bias lighting, USB LED strip, 1a86:fe07, USBHID, Prismatik alternative, OpenRGB alternative, SignalRGB unsupported device, Alienware AW3423DWF, ultrawide, HDR, Windows 11.
Freeware — free to use and to share the unmodified official release. Selling it and distributing modified versions are not allowed. No warranty. Full text: LICENSE.
FallenLight is an independent project, not affiliated with Robobloq, DX Light or SyncLight. All trademarks belong to their owners.
© 2026 Fallen