A system tray indicator for Ubuntu/GNOME that displays the current time in the French Revolutionary decimal time system. During the French Revolution, the Convention introduced a decimal time system: 10 hours per day, 100 minutes per hour, 100 seconds per minute. Décadi brings it to your desktop.
The indicator sits in your GNOME system tray and shows the current decimal time, updating every ~0.864 seconds (one decimal second):
⑩ 7:54:32
Click the indicator to see:
- Decimal time — updates live while the menu is open
- Standard time — 24-hour format, also live
- Revolutionary calendar date — e.g.
27 Prairial CCXXXIV(the full 12-month + Sansculottides calendar) - Show seconds — toggle to compact
⑩ 7:54mode - Quit — cleanly exits
| Standard | Decimal | Notes |
|---|---|---|
| 24 hours | 10 hours | Each decimal hour = 2.4 standard hours |
| 60 minutes | 100 minutes | Each decimal minute = 1.44 standard minutes |
| 60 seconds | 100 seconds | Each decimal second = 0.864 standard seconds |
| Midnight | 0:00:00 | Same |
| Noon | 5:00:00 | Halfway through the day |
| 6:00 PM | 7:50:00 |
The click menu also shows the current date in the French Republican Calendar:
- 12 months of 30 days each (Vendémiaire through Fructidor)
- 5-6 complementary days (Sansculottides) at year end
- Year numbering from the Republican epoch (September 22, 1792)
- Years displayed in Roman numerals (e.g. CCXXXIV = 234)
- Leap years follow the Romme convention
- Ubuntu with GNOME Shell (tested on 46+, Wayland and X11)
- GNOME Shell AppIndicator extension — required for tray indicators to appear:
Then enable it in GNOME Extensions or GNOME Tweaks. Log out and back in after enabling.
sudo apt install gnome-shell-extension-appindicator - Python 3.12+
- System packages (pre-installed on standard Ubuntu desktop):
sudo apt install python3-gi gir1.2-ayatanaappindicator3-0.1
Clone the repo:
git clone https://github.com/Avicennasis/decadi.git
cd decadiSymlink the autostart entry so it launches on login:
# Edit decadi.desktop first — update the Exec and Icon paths to match your clone location
ln -s "$(pwd)/decadi.desktop" ~/.config/autostart/decadi.desktopStart it now without waiting for a login:
python3 decadi.py &The included decadi.desktop file has hardcoded absolute paths. If you cloned to a different location than the default, edit the Exec and Icon lines to match:
Exec=python3 /your/clone/path/decadi.py
Icon=/your/clone/path/assets/transparent.pngOnce running, look for the ⑩ indicator in your system tray. It ticks every decimal second (~0.864 real seconds), so you'll see the seconds counter go past 59 into the 80s and 90s.
Single instance: If you accidentally launch it twice, the second instance detects the first via DBus and exits silently.
Clean shutdown: The indicator handles SIGTERM/SIGINT, so kill and session logout both work cleanly. Or just click Quit in the menu.
Autostart: The symlinked .desktop file ensures Décadi launches automatically on every login. To disable autostart, remove the symlink:
rm ~/.config/autostart/decadi.desktopThe project includes unit tests for all conversion logic:
python3 -m pytest tests/ -vTests cover decimal time conversion, Roman numeral conversion, and Revolutionary calendar date computation (including leap years and Sansculottides). The test suite runs headlessly — no display server required.
Décadi is a single Python file (decadi.py) with no external dependencies beyond the system GTK/AppIndicator packages. Key components:
- Decimal time conversion — wall-clock decomposition (
h*3600 + m*60 + s) scaled to 100,000 decimal seconds per day - Self-correcting timer — a one-shot GLib timer that recalculates the next decimal-second boundary from the wall clock on every tick, preventing drift
- Revolutionary calendar — counts days from the Republican epoch (September 22, 1792), accounting for the Romme leap year convention
- DBus single-instance — claims
systems.simmons.Decadion the session bus; duplicates exit silently
See CONTRIBUTING.md for guidelines.