A browser app that drives the Precision Clock Mk IV by mitxela over Web Serial — display modes, text & countdowns, brightness curves, a live polar sky, an orthographic globe and a flat world map, GPS / satellite / timing charts, and a raw serial monitor. With no clock attached it runs as a faithful emulator.
Note
Independent, community-built. Not affiliated with mitxela.
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There was a native macOS menu-bar app — it still exists, it's just on hold. A few reasons why:
- Distribution. A native Mac app requires signing + notarizing each build, which is a pain. A web app is a URL.
- Reach. Anyone on a Chromium browser can open it, no per-platform build, no updates to push.
- Knowledge. I know more HTML / JS / Canvas than I do Swift / AppKit.
- Clock control — display modes, text & scrolling marquee, countdowns, brightness / gamma / DAC curves, colon styles, and raw
key = valuecommands. - Sky room — a polar az/el plot with sector heatmap and age-faded trails, C/N₀ vs elevation + over time, a static-position CEP scatter with DOP history, an orthographic globe with a soft day/night terminator, and a flat world map with satellites at their real sub-points.
- Timing — PPS host-timestamping: phase jitter, drift staircase, and a temperature-compensation fit (with the draft firmware streaming
$PMTXTS). - Emulator — everything above runs with no hardware, driven by a built-in simulator; connect a real Mk IV over Web Serial and the same views drive the physical clock.
- Config & data — read/write the clock's
config.txt, REST data-sources for the date row, weather-at-fix, and a raw NMEA / serial monitor.
- Hosted: https://peterlewis.github.io/pcc/ — needs a Chromium browser (Chrome / Edge / Arc / Brave) over HTTPS.
- Local dev: live source, no build step:
git clone https://github.com/peterlewis/pcc.git cd pcc && bash web/serve.sh # http://localhost:8765
- Build the static site (what CI deploys):
cd web && npm install && node build.mjs # → ../docs/
Web Serial isn't in Safari or Firefox — use a Chromium browser. Nothing is required to look around (it emulates a clock); plug one in to drive the real thing.
| Path | What |
|---|---|
web/ |
The app — source. Built to docs/ by CI and served on Pages. See web/README.md. |
chrony-bridge/ |
Small host daemon feeding the clock's GPS time into chrony as a local NTP source. |
.github/workflows/pages.yml |
Builds web/ with esbuild and deploys to GitHub Pages on every push to main. |
main is web-only. The native macOS app is paused and preserved on the macos-app branch (kept as a Swift reference).
A browser can't open a UDP port, so for a real local NTP source there's a small cross-platform daemon that reads the clock's serial stream and feeds chrony through its SOCK refclock — handy on a headless Linux / Raspberry Pi box. Setup, honest accuracy notes and service files are in chrony-bridge/README.md.
The original native menu-bar app — three satellite views, GPS-disciplined NTP, WeatherKit, on-device AI insights — is paused in favour of the web version, but preserved and still buildable on its branch:
git fetch && git switch macos-app
cd macos && swift build && swift run PCC- Precision Clock Mk IV — official documentation
- clock4 — hardware design & firmware source (mitxela)
- Forum thread — discussion on the mitxela forum
MIT — see LICENSE. Bundled third-party assets (fonts, map data, libraries) keep their own licenses; see THIRD_PARTY.md.