ax206display

A Windows system-tray app that drives multiple USB AX206-based LCD screens (the common 3.5" 480x320 "USB LCD monitor" panels and similar), each with its own independently configured widget layout: system monitoring, images/GIFs, a clock, weather (Open-Meteo), UniFi, and Proxmox status.

The AX206 USB protocol is not publicly documented by its vendor; this project reverse-derives it from public reference implementations - see docs/protocol-spec.md for the full write-up, citations, and known gaps.

Download

Prebuilt Windows builds are published on the Releases page - no separate .NET install required either way:

• Ax206Display-*-win-x64.msi - the installer (recommended): adds a Start Menu shortcut and an Add/Remove Programs entry, and cleanly replaces the previous version on your next update instead of you hand-swapping exes.
• Ax206Display-*-win-x64.zip - the same app as a portable exe, for running without installing anything. It's a zip rather than a bare exe because Ax206Display.exe needs its bundled libusb-1.0.dll sitting right next to it - keep both files together wherever you unzip it.

Status

Currently at the M1 scaffold milestone: solution structure, the USB protocol layer, a mock transport for hardware-free development/testing, and a minimal tray app that renders a live clock widget end-to-end through the real compositor. The widget designer, multi-device widget persistence, and the UniFi/Proxmox/weather widgets themselves are future milestones - the underlying data-source clients already exist and are unit tested, but aren't yet wired into a widget UI.

Solution layout

Project	TFM	Purpose
Ax206Display.Protocol	net8.0	AX206 command/CBW/CSW byte-level protocol, no I/O
Ax206Display.Transport	net8.0	IAx206Transport + a mock, a LibUsbDotNet-based transport, and a WinUSB P/Invoke fallback
Ax206Display.Rendering	net8.0	SkiaSharp-based widget compositor and pixel-format conversion
Ax206Display.DataSources	net8.0	System sensors (LibreHardwareMonitorLib), Open-Meteo weather, UniFi, Proxmox clients
Ax206Display.Config	net8.0	JSON config models/service, DPAPI-backed secret store
Ax206Display.App	net8.0-windows	The WPF tray app: DI host, tray icon/menu, Task Scheduler auto-start, widget-designer window
Ax206Display.Tests	net8.0	xUnit tests for every project above except App

All USB I/O goes through the IAx206Transport interface so rendering/config/data-source code is fully testable without hardware (see Ax206Display.Transport.Mock). Device discovery never hardcodes a USB VID/PID: it probes candidate devices with the protocol's own GetLcdParameters command and accepts whichever respond plausibly.

Building

Requires the .NET 8 SDK.

# Everything except the WPF app (works on Linux/macOS/Windows):
dotnet build Ax206Display.CrossPlatform.slnf
dotnet test Ax206Display.CrossPlatform.slnf

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# Everything, including the WPF app (Windows only):
dotnet build Ax206Display.sln

CI (.github/workflows/ci.yml) mirrors this split: a Linux job builds and tests the cross-platform projects, and a windows-latest job builds the full solution including the WPF app.

Security

TLS to UniFi/Proxmox uses certificate pinning (IntegrationConfig.PinnedCertificateSha256Thumbprint), not a blanket "accept any certificate" bypass, since both commonly serve self-signed certs on a LAN. Secrets are DPAPI-encrypted at rest (Ax206Display.Config.Secrets) and their in-memory buffers are zeroed after use. The app currently runs elevated (requireAdministrator) for USB/Task Scheduler access; see docs/privilege-separation.md for a proposed design to shrink that to a minimal elevated broker process in a future milestone.

UniFi login needs a local-access-only admin account - a cloud/SSO-linked account can fail to authenticate through the API in confusing ways (e.g. a generic "invalid credentials" response even with the right password) that have nothing to do with this app. If Test & Save keeps failing, check Settings → Admins → the account in question and confirm it's set to local access rather than linked to a Ubiquiti cloud account. If you'd rather keep 2FA enabled on that account instead of switching it to local-only, the app supports that too (IntegrationConfig.TotpSecretKey, computed via Ax206Display.DataSources.Auth.TotpGenerator) - enter the base32 setup key/secret from when you enabled 2FA, not a live 6-digit code.

The build enforces TreatWarningsAsErrors with AnalysisLevel=latest-recommended, pins the full dependency graph via packages.lock.json + Directory.Packages.props, and gates CI on NuGetAudit/dotnet list package --vulnerable.