speedo

A monochrome, fullscreen GPS speedometer with a speed-reactive 3D starfield, designed for testing in the Tesla in-car browser.

Open live GPS · Preview the speed effect

Use it

1. Park the vehicle safely.
2. Open the live site in the Tesla browser.
3. Choose a launch mode:
   • Enter fullscreen uses the same YouTube redirect route used by Tesla fullscreen launchers, then starts GPS automatically when it returns.
   • Start without fullscreen stays in the normal Tesla browser and is the fallback if Theater is unavailable or closes while moving.
4. Allow location access if the browser asks.
5. Leave the display open while driving. Do not interact with it while the vehicle is moving.

The page requests high-accuracy browser geolocation through browser-car-speed. The package prefers the browser's reported speed, falls back to guarded distance-over-time estimates, filters noisy readings, detects movement, and marks stale data unavailable. Speedo keeps only the display animation and in-car UI behavior. The npm package is bundled into the site, so the live display does not depend on a third-party CDN.

As speed increases, the starfield accelerates and stretches into depth. This is only a visual effect; it does not change the speed reading.

Speed is indicative GPS data, not Tesla telemetry and not a replacement for the vehicle speedometer.

The Tesla Theater redirect is an unofficial compatibility technique, is generally parked-only, and may change with a future vehicle software update. The standard mode remains fully usable with Tesla's browser chrome. Other browsers use the standard Fullscreen API with a full-viewport CSS fallback.

Privacy

Location is processed only in the browser. This project has no analytics, account, backend, or location upload.

Preview locally

Install dependencies, build the self-hosted site, and serve its output:

npm ci
npm run build
python3 -m http.server 4173 --directory _site

Then open http://localhost:4173/. Add ?demo=1 for a synthetic speed preview without granting location.

Development

npm ci
npm run verify

Pushes to main are tested and deployed with GitHub Actions.

Font

Oxanium is distributed under the SIL Open Font License. See assets/OFL.txt.

License

MIT