TriGlyph

Three glyphs, driven properly.
A clean-room control panel for the KF420 / KF620 DGT three-digit USB temperature display.

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✨ Highlights

• 🧩 One self-contained TriGlyph.exe (~146 MB) — no installer, no admin rights, no kernel driver, no vendor DLLs, no HWiNFO.
• 🔌 Pluggable temperature sources tried in priority order, with honest failure reporting. Nothing is ever fabricated.
• 🧪 Report descriptor decoder reads the panel's undocumented 205-byte descriptor over IOCTL_HID_GET_REPORT_DESCRIPTOR.
• 🎛️ Raw feature-report console with a safety gate, auto-detection with manual pinning, four editable themes.
• 🖥️ Tray icon drawn at runtime and coloured by temperature; run-at-login via HKCU\...\Run.

📥 Download

Grab the latest build from the Releases page.

TriGlyph.exe   (~146 MB, self-contained, win-x64)
themes/        (ship beside the exe)

1. Copy TriGlyph.exe and the themes/ folder to the target machine.
2. Run it — it lives in the tray; the tray icon is coloured by temperature.
3. Open Advanced → Re-read to decode your panel's report descriptor.

💡 For accurate CPU package temperature without a driver, run LibreHardwareMonitor alongside it. That is the trade the vendor tool made differently — by bundling a driver.

🎯 Why this exists

The vendor "JL DGT" tool works, but it is worth replacing:

Concern	Vendor tool	TriGlyph
Kernel driver	Bundles a renamed copy of HWiNFO32.DLL (api-ms-win-core-sysinfo-825-64.dll) hiding HWiNFO_x64_205.sys ring-0 driver	❌ None
Elevation	Requires Administrator	✅ User-level
Install footprint	Installs a kernel service	✅ Portable, nothing installed
Debug artifacts	Ships DeviceDriver.pdb, .iobj, .ipdb	✅ Clean
Licensing	Renamed HWiNFO SDK masquerading as Windows API-set DLLs	✅ Clean-room

Nothing there looks deliberately malicious — it is HWiNFO's SDK, renamed — but the masquerade is a licensing violation and a technique AV heuristics rightly flag. TriGlyph requires no elevation, installs nothing, and touches no other process's memory.

🔌 Temperature sources

Tried in priority order, with honest failure:

LibreHardwareMonitor WMI → OpenHardwareMonitor WMI → HWiNFO shared memory
→ AIDA64 shared memory → ACPI thermal zone → Windows temperature probe → Manual value

Unavailable sources are reported, never fabricated. Missing sources from a newer build are merged into your saved priority list automatically on load.

🧠 The hardware

Property	Value
USB identity	1a2c:4184 (China Resource Semico), shared by KF400/KF420/KF620 DGT
Interfaces	2 — interface 0 is a fake keyboard, interface 1 is the panel
Endpoints	Interrupt IN only — no OUT endpoint
Host → device	Control transfers only, i.e. HID feature reports
Temperature report	Feature report 7, 64 bytes: [7, 0xFF, 0xFF, hundreds, tens, ones]
Resolution	Whole degrees, three independent decimal digits

Because there is no OUT endpoint, the panel is a dumb peripheral: firmware renders the digits and the host only pushes a number. Nothing here needs a driver.

Full detail, including what is not known: docs/PROTOCOL.md.

🛡️ Safety

The raw console blocks writes to report ids other than 7 unless you arm unsafe writes. This is not hypothetical — the reference project records that a bad USB state left a panel unconfigured (can't set config #1, error -32) until reboot.

Writes to input reports are refused outright: those are read-only, and an attempt means the report was misidentified.

⚙️ Configuration

• Settings live at %APPDATA%\TriGlyph\settings.json — hand-editable, string enums, unknown keys tolerated, out-of-range values clamped on load.
• Themes are themes/*.json (glass, softlight, industrial, editorial). Drop in your own; a user file overrides a built-in of the same name. Invalid colours are repaired rather than rejected.

🏗️ Building

./build.sh

Runs the tests, publishes win-x64 self-contained single-file, and patches the PE subsystem. See docs/BUILDING.md for the off-Windows details.

🧪 Testing

dotnet test tests/TriGlyph.Tests/TriGlyph.Tests.csproj

102 tests, all runnable on Linux. Every piece with real behaviour lives in TriGlyph.Core behind interfaces, so the interesting logic is testable without Windows — including the whole read → smooth → encode → write pipeline, with failover, range rejection, staleness and duplicate suppression.

Design rationale: docs/ARCHITECTURE.md.

📋 Known limitations

• No version resource in the published exe — MSBuild cannot add apphost resources off Windows (NETSDK1074). The window icon is embedded as a WPF resource, and the PE subsystem is patched to GUI, so no console window appears.
• Display blanking is not implemented. No blank/off command is known.
• RGB and fan control are not reachable — the ARGB fans connect to the motherboard's ARGB header and the fan to a PWM header, neither through this device.
• Only temperature semantics are enforced (0–150 °C). The hardware accepts any three digits, so other values can be sent via the raw console.

📚 Documentation

Document	Contents
docs/PROTOCOL.md	The hardware protocol, what is measured vs guessed
docs/ARCHITECTURE.md	Module map and design decisions
docs/BUILDING.md	Building, including off-Windows caveats
CHANGELOG.md	Release history

🗂️ Repository layout

src/TriGlyph.Core     pure net10.0, no Windows dependencies — all behaviour, all tests
src/TriGlyph.App      net10.0-windows WPF — interop, sources, services, views
tests/TriGlyph.Tests  xunit, runs on Linux
docs/                 protocol, architecture, build notes
tools/                patch-subsystem.py, standalone probe
themes/               shipped beside the exe
build.sh              tests -> publish -> subsystem patch

🙏 Credits

• njt1982/tzmrit-dgt-linux — the independent daemon that verified the temperature report this project encodes.
• liquidctl/liquidctl issue #817 — the lsusb -v dump the interface layout comes from.

Neither is affiliated with this project.

📄 License

MIT — see LICENSE. Made with ❤️ for cleaner USB HID tooling.