Glint

Type and speak with your eyebrows and your breath.

Download · How it works · Privacy · Run from source

A webcam switch-access keyboard for people who can't reliably use their hands or voice, built on the Presage SmartSpectra Node SDK. No special hardware, no cloud service, no account.

How you use it

A highlight steps through the board on its own. You need two gestures:

Gesture	Does	Read from
Raise your eyebrows	Select the highlighted row, then the highlighted key	face landmarks (brow-to-eye distance)
Breathe out slowly (about 3 s)	Speak the sentence aloud and copy it to the clipboard	chest breathing trace

• Back and delete are keys: ↩ ends every row and ⌫ is on the first letter row.
• Letters are in frequency order (space, E, T, A, O first), so the common ones take the fewest steps.
• Quick phrases on the top row ("Yes", "I need water", "I need help" …) are spoken as soon as you select them.
• A keyboard or physical switch works too: Space select · Enter speak · Esc stop.

Screens

Consent first. The camera can only be started from here, after the user has read what is read and what is kept.	Settings, for the user or a carer: scan speed, the six quick phrases, SDK telemetry (off by default), and Forget everything.

How it works

SDK signal	What Glint does with it
face.landmarks (478 points)	Brow-to-eye distance ÷ eye spacing → select when it rises about 28% and holds
breathing.upperTrace	Rises on inhale, falls on exhale. A gentle fall of ≥ 6 units for ≥ 2.5 s → speak
face.talking	Blocks speaking while you are talking
validationStatus + hint	Scanning pauses and shows the SDK's own hint ("Increase light on face", or a hint when more than one face is visible …)
cardio.pulseRate	Shown in the strip so you can see you're being read. Never used for any decision

The detectors are small pure functions (src/renderer/gestures/), tuned and tested on a real recorded session with timestamped gesture cues (recordings/guided.jsonl: numbers only, no video). Everything the SDK measured is in docs/sdk-notes.md.

Why eyebrows and not blinks? The plan was a long blink to select. On the recorded session, five deliberate 1-second eye closures were invisible to both the SDK's blink signal and the face landmarks: the user wears thick-framed glasses and sat in dim light. Eyebrow raises showed up every time (+40%). So the gesture set follows the measurements.

Privacy and consent

• The camera starts only from the consent screen and is released on Stop, Esc, any error that ends the session, or closing the app.
• Video is processed on the device by the SDK. Glint never writes it to disk or sends it anywhere.
• Nothing you type or say is stored. Spoken text goes to the clipboard and nowhere else.
• The only stored file is settings.json in the app's user-data folder. Forget everything deletes it.
• SDK telemetry (session summaries and readiness reports; no frames, no vitals, but not anonymous: it can be linked to your Presage account) is off unless you turn it on. See Presage telemetry & privacy.
• No LLM Insights, no AI service, no analytics, no accounts.
• Glint is not a medical device and makes no health judgements.

Run

Needs Node ≥ 20 and a free API key from physiology.presagetech.com.

npm install
cp .env.example .env   # put your key in PRESAGE_API_KEY
npm start              # GLINT_DEVTOOLS=1 npm start opens DevTools

No key or no camera? Choose Try a recorded session on the first screen. It replays a recorded session through the same detectors, and you can type with Space / Enter.

Linux speech: most distros give Chromium no built-in voice, so Glint falls back to espeak-ng (sudo pacman -S espeak-ng / sudo apt install espeak-ng). Without it, text is still copied.

Light matters. Sit facing a lamp or window. A face in shadow is the most common reason tracking fails.

The SDK supports Linux x64 (glibc ≥ 2.35), Windows x64 and macOS arm64.

Download

Builds are on the Releases page (made by CI): Glint-<version>-linux-x86_64.AppImage and Glint-<version>-win-x64.exe. They are unsigned, so Windows SmartScreen will ask you to confirm.

• Linux: chmod +x Glint-*.AppImage && ./Glint-*.AppImage. If it says AppImages require FUSE (Arch, Ubuntu 22.04+), run APPIMAGE_EXTRACT_AND_RUN=1 ./Glint-*.AppImage or install libfuse2.
• API key for an installed app: set PRESAGE_API_KEY in your environment, or put PRESAGE_API_KEY=… in a .env file in the app's user-data folder (~/.config/Glint/ on Linux, %APPDATA%\Glint\ on Windows). The key is never bundled into a build.

Build locally with npm run dist:linux (or dist:win on Windows). Output goes to out/.

Documentation

yashksaini-coder.github.io/glint. The source is in site/, built with Fumadocs: cd site && npm install && npm run dev. Pages are plain MDX in site/content/docs, starting with Scope (what has and hasn't been tested).

Develop

npm test                     # detectors on the recorded fixture, scanner, settings validation
npm run smoke                # launches the app, replays, types + speaks via simulated switch presses
node tools/screenshots.ts    # regenerates the app screenshots in docs/img/ (replay mode: no camera, no face)
npm run diagram              # regenerates docs/img/architecture.png from tools/diagram/make.mjs
cd site && npm run og        # regenerates the share images (site/public/og.png, docs/img/social-preview.png)
node tools/sweep.ts          # grid-searches detector thresholds against the recorded cues

src/main/        Electron main: SDK IPC, camera permission, settings file, clipboard, espeak fallback
src/preload/     bridge (SDK preload + a small window.glint API)
src/renderer/    app.ts (consent → setup → board), gestures/, board/, signals/ (live + replay)
src/shared/      settings schema + sanitizer (used on both sides)
recordings/      guided.jsonl test fixture
tools/           analysis, tuning, smoke test, screenshots

Status

Entry for the DEV × Presage SmartSpectra challenge (Nov 2026). Done: consent flow, scanning board, quick phrases, settings, both detectors, replay mode, Linux/Windows builds. Next: per-user calibration, demo video.

License

Glint's own code is MIT. The Presage SmartSpectra SDK (@smartspectra/node-sdk and its platform runtimes) is proprietary and under Presage's own terms; packaged builds include its runtime and its bundled third-party notices (resources/smartspectra/).