Venus OS Boat Addons

Custom addons for a Cerbo GX running Venus OS on a sailboat. These services extend the system with weather monitoring, tide prediction, navigation tracking, generator management, and custom MFD displays.

All D-Bus services follow the same deployment pattern: build a .tar.gz package, copy it to /data/ on the Cerbo GX, and run install.sh. Services are managed by daemontools and survive firmware updates via rc.local.

Projects

Project	Type	Language	Description
axiom-nmea	Library + Service	Python	Decodes Raymarine LightHouse protobuf multicast into NMEA 0183 sentences and Venus OS D-Bus services. Includes protocol documentation, debug tools, and a deployable D-Bus publisher.
dbus-generator-ramp	D-Bus Service	Python	Gradually ramps inverter/charger input current when running on generator to avoid overload. Features warm-up hold, overload detection with fast recovery, and a persistent power correlation learning model.
dbus-lightning	D-Bus Service	Python	Monitors real-time lightning strikes from the Blitzortung network via WebSocket. Filters by distance, analyzes storm approach speed, and estimates ETA.
dbus-meteoblue-forecast	D-Bus Service	Python	Fetches 7-day weather forecasts from the Meteoblue API (wind, waves, precipitation, temperature). Adjusts refresh rate based on boat movement.
dbus-no-foreign-land	D-Bus Service	Python	Sends GPS position and track data to noforeignland.com. Includes a QML settings page for the Venus OS GUI.
dbus-tides	D-Bus Service	Python	Predicts tides by combining depth sensor readings with harmonic tidal models (NOAA stations and coastal grid). Records depth history in SQLite, detects high/low tides, and calibrates to chart depth.
dbus-vrm-history	D-Bus Service	Python	Proxies historical data from the VRM cloud API and exposes it on D-Bus/MQTT for the frontend dashboard.
dbus-windy-station	D-Bus Service	Python	Uploads weather observations from Raymarine sensors to Windy.com Stations API. Supports both legacy and v2 Venus OS GUI plugins.
mfd-custom-app	Deployment Package	Shell	Builds and deploys the custom HTML5 app to the Cerbo GX. Overrides the stock Victron app with custom pages served via nginx. Supports SSH and USB installation.
venus-html5-app	Frontend App	TypeScript/React	Fork of the Victron Venus HTML5 app with custom Marine2 views for weather, tides, tracking, generator status, and mooring. Displayed on Raymarine Axiom and other MFDs.
watermaker	UI + API Docs	React/JS	Control interface for a watermaker PLC system. React SPA with REST/WebSocket/MQTT integration. Backend runs on a separate PLC controller.

Common D-Bus Service Structure

All Python D-Bus services share this layout:

dbus-<name>/
├── <name>.py              # Main service entry point
├── config.py              # Configuration constants
├── service/
│   ├── run                # daemontools entry point
│   └── log/run            # multilog configuration
├── install.sh             # Venus OS installation
├── uninstall.sh           # Cleanup
├── build-package.sh       # Creates deployable .tar.gz
└── README.md

At install time, install.sh symlinks velib_python from /opt/victronenergy/, registers the service with daemontools, and adds an rc.local entry for persistence across firmware updates.

Deployment

# Build a package
cd dbus-<name>
./build-package.sh

# Copy to Cerbo GX
scp dbus-<name>-*.tar.gz root@<cerbo-ip>:/data/

# Install on device
ssh root@<cerbo-ip>
cd /data && tar -xzf dbus-<name>-*.tar.gz
bash /data/dbus-<name>/install.sh

# Check service status
svstat /service/dbus-<name>
tail -f /var/log/dbus-<name>/current | tai64nlocal

Development Prerequisites

• Python 3.8+ -- for all D-Bus services
• Node.js 20+ and npm -- for venus-html5-app and watermaker UI
• SSH/root access to the Cerbo GX
• Venus OS v3.10+ on the target device

Sensitive Configuration

Some projects require API keys or credentials. These are excluded from version control. Copy the example templates and fill in your values:

• dbus-meteoblue-forecast/forecast_config.example.json --> forecast_config.json
• dbus-windy-station/station_config.example.json --> station_config.json
• watermaker/ui/.env.example --> .env

New Project Template

See _template/ for a skeleton D-Bus service with all the boilerplate: main script, config, daemontools service, install/uninstall scripts, and build packaging.