venus/axiom-nmea/examples/dbus-raymarine-publisher/README.md

Raymarine D-Bus Publisher

Publishes Raymarine sensor data to Venus OS via D-Bus, making it available to the Victron ecosystem (VRM, GX Touch display, etc.). Also runs an NMEA TCP server for navigation apps.

Published Services

Service	Description
com.victronenergy.gps.raymarine_0	GPS position, speed, course
com.victronenergy.meteo.raymarine_0	Wind direction/speed, air temp, pressure
com.victronenergy.navigation.raymarine_0	Heading, depth, water temperature
com.victronenergy.tank.raymarine_tankN_0	Tank level for each tank
com.victronenergy.battery.raymarine_batN_0	Battery voltage for each battery

Quick Deployment

1. Build the package

From the examples/dbus-raymarine-publisher directory:

./build-package.sh

This creates dbus-raymarine-publisher-1.0.0.tar.gz with the following structure:

dbus-raymarine-publisher/
  raymarine_nmea/       # Python library
  venus_publisher.py    # Publisher script
  service/              # Daemontools service files
  install.sh            # Installation script
  uninstall.sh          # Removal script
  README.md             # This file
  VERSION               # Build info

2. Copy to Venus OS

scp dbus-raymarine-publisher-1.0.0.tar.gz root@venus:/data/

3. Extract on Venus OS

ssh root@venus
cd /data
tar -xzf dbus-raymarine-publisher-1.0.0.tar.gz

4. Run the installer

bash /data/dbus-raymarine-publisher/install.sh

The installer will:

• Find velib_python and create a symlink
• Prompt you to select a network interface (eth0, wlan0, or custom IP)
• Configure the NMEA TCP server port
• Install the daemontools service
• Set up automatic logging
• Configure rc.local for firmware update survival

4b. Or test manually first

cd /data/dbus-raymarine-publisher
python3 venus_publisher.py --interface eth0

Service Management

After installation, control the service with:

# Check status
svstat /service/dbus-raymarine-publisher

# View logs
tail -F /var/log/dbus-raymarine-publisher/current | tai64nlocal

# Stop service
svc -d /service/dbus-raymarine-publisher

# Start service
svc -u /service/dbus-raymarine-publisher

# Restart service
svc -t /service/dbus-raymarine-publisher

Changing the Network Interface

Edit the run script:

vi /data/dbus-raymarine-publisher/service/run

Change the INTERFACE variable to eth0, wlan0, or a specific IP address.

Then restart the service:

svc -t /service/dbus-raymarine-publisher

Surviving Firmware Updates

The installer automatically configures /data/rc.local to restore the service symlink after Venus OS firmware updates.

Uninstalling

bash /data/dbus-raymarine-publisher/uninstall.sh

To completely remove all files:

rm -rf /data/dbus-raymarine-publisher /var/log/dbus-raymarine-publisher

Command Line Options

Option	Description
--interface IP	Network interface or IP (default: 198.18.5.5)
--no-gps	Disable GPS service
--no-meteo	Disable Meteo (wind) service
--no-navigation	Disable Navigation service (heading, depth, water temp)
--no-tanks	Disable all Tank services
--no-batteries	Disable all Battery services
--tank-ids 1,2,10	Only publish specific tanks
--battery-ids 11,13	Only publish specific batteries
--update-interval MS	D-Bus update interval (default: 1000ms)
--nmea-tcp-port PORT	NMEA TCP server port (default: 10110)
--no-nmea-tcp	Disable NMEA TCP server
--debug	Enable debug logging
--dry-run	Listen without D-Bus registration

D-Bus Path Reference

GPS (com.victronenergy.gps)

Path	Description	Unit
/Position/Latitude	Latitude	degrees
/Position/Longitude	Longitude	degrees
/Speed	Speed over ground	m/s
/Course	Course over ground	degrees
/Fix	GPS fix status	0=no fix, 1=fix

Meteo (com.victronenergy.meteo)

Path	Description	Unit
/WindDirection	True wind direction	degrees
/WindSpeed	True wind speed	m/s
/ExternalTemperature	Air temperature	C
/Pressure	Barometric pressure	hPa

Navigation (com.victronenergy.navigation)

Path	Description	Unit
/Heading	True heading	degrees
/Depth	Depth below transducer	m
/WaterTemperature	Water temperature	C

Tank (com.victronenergy.tank)

Path	Description	Unit
/Level	Tank level	0-100%
/Remaining	Remaining volume	m3
/Capacity	Tank capacity	m3
/FluidType	Fluid type	enum
/Status	Sensor status	0=OK

Fluid types: 0=Fuel, 1=Fresh water, 2=Waste water, 3=Live well, 4=Oil, 5=Black water

Battery (com.victronenergy.battery)

Path	Description	Unit
/Dc/0/Voltage	Battery voltage	V
/Soc	State of charge (estimated)	%
/Alarms/LowVoltage	Low voltage alarm	0/1/2
/Alarms/HighVoltage	High voltage alarm	0/1/2

Testing with dbus-spy

On Venus OS, use dbus-spy to view published data:

# List all Raymarine services
dbus -y | grep raymarine

# Read GPS position
dbus -y com.victronenergy.gps.raymarine_0 /Position/Latitude GetValue
dbus -y com.victronenergy.gps.raymarine_0 /Position/Longitude GetValue

# Read navigation data
dbus -y com.victronenergy.navigation.raymarine_0 /Heading GetValue
dbus -y com.victronenergy.navigation.raymarine_0 /Depth GetValue

# Read wind data
dbus -y com.victronenergy.meteo.raymarine_0 /WindDirection GetValue
dbus -y com.victronenergy.meteo.raymarine_0 /WindSpeed GetValue

# Read tank levels
dbus -y com.victronenergy.tank.raymarine_tank1_0 /Level GetValue

Network Requirements

The Venus OS device must be connected to the same network as the Raymarine LightHouse MFD. The service will use the selected interface (eth0 or wlan0) and resolve the IP address at runtime, which works with DHCP.

If you need a specific VLAN IP (e.g., 198.18.x.x), you can add it manually:

# Add VLAN interface (temporary)
ip addr add 198.18.4.108/16 dev eth0

# Or configure in /etc/network/interfaces for persistence

MQTT Access

Venus OS includes an MQTT broker that mirrors all D-Bus values, allowing external systems (Home Assistant, Node-RED, SignalK, etc.) to access sensor data.

Enabling MQTT

On the GX device (or Venus OS):

1. Go to Settings > Services > MQTT
2. Enable MQTT on LAN
3. Optionally enable MQTT on LAN (SSL) for encrypted connections

Default ports:

• 1883 - MQTT (unencrypted)
• 8883 - MQTT with SSL

MQTT Topic Structure

Venus OS uses this topic structure:

N/<portal_id>/<service_type>/<instance>/<path>

Where:

• N/ - Notification topic (read values)
• <portal_id> - Unique VRM portal ID (e.g., b827eb123456)
• <service_type> - Service category (gps, tank, battery, meteo, navigation)
• <instance> - Device instance number
• <path> - D-Bus path without leading slash

To write values, use W/ prefix instead of N/.

Raymarine Sensor MQTT Topics

GPS Topics

MQTT Topic	Description	Unit
N/<id>/gps/0/Position/Latitude	Latitude	degrees
N/<id>/gps/0/Position/Longitude	Longitude	degrees
N/<id>/gps/0/Speed	Speed over ground	m/s
N/<id>/gps/0/Course	Course over ground	degrees
N/<id>/gps/0/Fix	GPS fix status	0=no fix, 1=fix

Meteo/Wind Topics

MQTT Topic	Description	Unit
N/<id>/meteo/0/WindDirection	True wind direction	degrees
N/<id>/meteo/0/WindSpeed	True wind speed	m/s
N/<id>/meteo/0/ExternalTemperature	Air temperature	C
N/<id>/meteo/0/Pressure	Barometric pressure	hPa

Navigation Topics

MQTT Topic	Description	Unit
N/<id>/navigation/0/Heading	True heading	degrees
N/<id>/navigation/0/Depth	Depth below transducer	m
N/<id>/navigation/0/WaterTemperature	Water temperature	C

Tank Topics

Each tank is published as a separate instance. With default tank configuration:

Tank	Instance	MQTT Base Topic
Fuel Starboard (ID 1)	0	N/<id>/tank/0/...
Fuel Port (ID 2)	1	N/<id>/tank/1/...
Water Bow (ID 10)	2	N/<id>/tank/2/...
Water Stern (ID 11)	3	N/<id>/tank/3/...
Black Water (ID 100)	4	N/<id>/tank/4/...

Available paths per tank instance:

Path Suffix	Description	Unit
/Level	Tank fill level	0-100%
/Remaining	Remaining volume	m3
/Capacity	Total capacity	m3
/FluidType	Fluid type enum	see below
/Status	Sensor status	0=OK
/CustomName	Tank name	string

Example full topics for Fuel Starboard tank:

N/<id>/tank/0/Level
N/<id>/tank/0/Remaining
N/<id>/tank/0/Capacity
N/<id>/tank/0/FluidType

Battery Topics

Each battery is published as a separate instance. With default battery configuration:

Battery	Instance	MQTT Base Topic
House Bow (ID 11)	0	N/<id>/battery/0/...
House Stern (ID 13)	1	N/<id>/battery/1/...
Engine Port (ID 1000)	2	N/<id>/battery/2/...
Engine Starboard (ID 1001)	3	N/<id>/battery/3/...

Available paths per battery instance:

Path Suffix	Description	Unit
/Dc/0/Voltage	Battery voltage	V DC
/Soc	State of charge (estimated)	0-100%
/Alarms/LowVoltage	Low voltage alarm	0/1/2
/Alarms/HighVoltage	High voltage alarm	0/1/2
/CustomName	Battery name	string

Example full topics for House Bow battery:

N/<id>/battery/0/Dc/0/Voltage
N/<id>/battery/0/Soc
N/<id>/battery/0/Alarms/LowVoltage

MQTT Message Format

Values are published as JSON:

{"value": 25.4}

For string values:

{"value": "Fuel Starboard"}

Subscribing to All Raymarine Sensors

# Subscribe to all GPS data
mosquitto_sub -h <venus_ip> -t 'N/+/gps/#' -v

# Subscribe to all navigation data
mosquitto_sub -h <venus_ip> -t 'N/+/navigation/#' -v

# Subscribe to all tank data
mosquitto_sub -h <venus_ip> -t 'N/+/tank/#' -v

# Subscribe to all battery data
mosquitto_sub -h <venus_ip> -t 'N/+/battery/#' -v

# Subscribe to all meteo/wind data
mosquitto_sub -h <venus_ip> -t 'N/+/meteo/#' -v

# Subscribe to everything
mosquitto_sub -h <venus_ip> -t 'N/#' -v

Keep-Alive Requirement

Venus OS MQTT requires periodic keep-alive messages to continue receiving updates. Send an empty message to the read topic:

# Initial subscription request
mosquitto_pub -h <venus_ip> -t 'R/<portal_id>/system/0/Serial' -m ''

# Or request all values
mosquitto_pub -h <venus_ip> -t 'R/<portal_id>/keepalive' -m ''

For continuous monitoring, send keep-alive every 30-60 seconds.

Home Assistant Integration

Example MQTT sensor configuration for Home Assistant:

mqtt:
  sensor:
    # GPS Position
    - name: "Boat Latitude"
      state_topic: "N/<portal_id>/gps/0/Position/Latitude"
      value_template: "{{ value_json.value }}"
      unit_of_measurement: "deg"

    - name: "Boat Longitude"
      state_topic: "N/<portal_id>/gps/0/Position/Longitude"
      value_template: "{{ value_json.value }}"
      unit_of_measurement: "deg"

    - name: "Boat Speed"
      state_topic: "N/<portal_id>/gps/0/Speed"
      value_template: "{{ (value_json.value * 1.94384) | round(1) }}"
      unit_of_measurement: "kn"

    # Navigation
    - name: "Boat Heading"
      state_topic: "N/<portal_id>/navigation/0/Heading"
      value_template: "{{ value_json.value }}"
      unit_of_measurement: "deg"

    - name: "Water Depth"
      state_topic: "N/<portal_id>/navigation/0/Depth"
      value_template: "{{ (value_json.value * 3.28084) | round(1) }}"
      unit_of_measurement: "ft"

    # Tank Levels
    - name: "Fuel Starboard"
      state_topic: "N/<portal_id>/tank/0/Level"
      value_template: "{{ value_json.value }}"
      unit_of_measurement: "%"
      device_class: battery

    - name: "Fresh Water Bow"
      state_topic: "N/<portal_id>/tank/2/Level"
      value_template: "{{ value_json.value }}"
      unit_of_measurement: "%"

    # Battery Voltage
    - name: "House Battery Voltage"
      state_topic: "N/<portal_id>/battery/0/Dc/0/Voltage"
      value_template: "{{ value_json.value | round(2) }}"
      unit_of_measurement: "V"
      device_class: voltage

Node-RED Integration

Example Node-RED flow to monitor tank levels:

1. Add mqtt in node subscribed to N/<portal_id>/tank/+/Level
2. Add json node to parse the message
3. Add function node:

   msg.payload = msg.payload.value;
   msg.topic = msg.topic.split('/')[3]; // Extract tank instance
   return msg;
   

4. Connect to dashboard gauge or further processing

SignalK Integration

SignalK can subscribe to Venus MQTT and convert values to SignalK paths. Install the signalk-venus-plugin for automatic integration, or manually map MQTT topics in the SignalK server configuration.

Troubleshooting

No D-Bus services registered

• Check that velib_python is installed (pre-installed on Venus OS)
• Ensure dbus-python with GLib support is available

No data received

• Verify network interface is configured correctly
• Check that the Raymarine MFD is broadcasting on the network
• Use --debug to see raw packet data

Stale data

• Data older than 10-30 seconds is marked as stale
• Check network connectivity to Raymarine multicast groups

Service won't start

• Check logs: tail /var/log/dbus-raymarine-publisher/current
• Verify run script is executable: ls -la /service/dbus-raymarine-publisher/run
• Check service status: svstat /service/dbus-raymarine-publisher