Backgammon Clock

A two-player match clock with simple delay you can actually see. Reserve time plus a fixed number of free seconds each turn that never carry over — the Backgammon Galaxy control. Defaults to 3:00 + 15s.

Plain HTML, CSS and JavaScript. No frameworks, no fonts, no images, no network.

Getting it onto your phone

Chrome will only offer a real install over HTTPS, so the file needs a host. GitHub Pages is free and takes about two minutes:

Create a new public repository, e.g. bgclock.
Upload all six files to the root: index.html, manifest.webmanifest, sw.js, icon-192.png, icon-512.png, icon-maskable-512.png.
Settings → Pages → Source: Deploy from a branch → main / (root) → Save.
Wait a minute, then open https://<you>.github.io/bgclock/ in Chrome on Android.
Chrome menu (⋮) → Add to Home screen → Install.

Open it from the home-screen icon and it runs fullscreen with no browser chrome, offline, with the screen kept awake while a game is on.

If you're using a different path than /bgclock/, edit the "id" field in manifest.webmanifest to match, or just delete that line.

To try it before hosting, open index.html in any browser — everything works except installation and the service worker.

Using it

Tap your own half to end your turn and start your opponent's clock. At the start, whoever taps first sets the other player going.
The waiting player's taps are ignored, so a stray hand won't stop the clock.
The bar under the big time is the delay draining. When it empties you get a soft tick and your reserve starts moving. That's the moment worth hearing.
Reset returns to the starting position. Pause freezes mid-turn and resumes exactly where it stopped, delay included.

Backgammon clocks pause between games, and after a cocked die the delay is normally restarted — use pause and reset for those.

Settings

Setting	Range	Default
Time	0:15 – 99:00	3:00
Delay	0 – 60 s	15 s
Colour	Sage, Brass, Slate, Teal, Plum	Sage
Sound	on / off	on

Brass is the colour in the chess.com app, if you want the exact original look. Changing time or delay resets the clock. Settings are remembered on the device.

Sounds

All three are generated with the Web Audio API, so there are no audio files to download and nothing to attribute.

Turn change — a soft rising fifth with an octave partial, marimba-like.
Delay expiry — a single quiet 300 Hz tick, deliberately easy to miss unless you're listening for it.
Time out — a falling triad, loud and unambiguous.

Licence

Do whatever you like with it.