signalk-sailsense

A Signal K plugin that connects to a SailSense Hub over MQTT and publishes all sensor data as raw Signal K values.

What it does

The SailSense Hub exposes boat data — batteries, tanks, breakers, actions, GPS, wind, depth, and power rail telemetry — over a local MQTT broker. This plugin subscribes to all of those topics and forwards every value into Signal K under a sailsense.* path namespace, making the data available to any Signal K instrument, logger, or automation.

Installation

Install from the Signal K AppStore inside the Signal K server UI, or via npm:

npm install signalk-sailsense

Then restart your Signal K server and enable the plugin under Server → Plugin Config → SailSense Hub.

Configuration

| Field | Default | Description | |---|---|---| | MQTT Broker Host | 192.168.50.231 | IP address or hostname of the SailSense Hub on your local network | | MQTT Broker Port | 1883 | MQTT port (standard; change only if you've customised the Hub) |

Topic groups

Each topic group can be toggled independently in the plugin config UI to reduce noise:

| Group | Default | Covers | |---|---|---| | Batteries | enabled | Voltage, current, charge level, alerts | | Tanks | enabled | Fuel, fresh water, blackwater levels and alerts | | Actions | enabled | Lights, pumps, and switch states | | Breakers | enabled | Circuit breaker on/off states | | Hub | enabled | GPS, wind, depth, IMU, Wi-Fi, Zigbee | | Powernet | enabled | Power rail voltmeters, analog inputs, output states | | UI Config | disabled | Hub interface configuration blobs (high-volume, low-value) |

Signal K paths

MQTT topics are mapped to Signal K paths by:

1. Stripping structural children segments
2. Replacing / with .
3. Prefixing with sailsense.

Some examples:

| MQTT topic | Signal K path | |---|---| | batteries/children/Main/children/Bank1/voltage | sailsense.batteries.Main.Bank1.voltage | | tanks/children/water_tanks/children/water_tank_portside/levels/pct | sailsense.tanks.water_tanks.water_tank_portside.levels.pct | | Hub/telematic/signalprocessed/rx | sailsense.Hub.telematic.signalprocessed.rx | | breakers/children/HIFI/state | sailsense.breakers.HIFI.state | | powernet/device/powerail/1/voltmeters/1/value | sailsense.powernet.device.powerail.1.voltmeters.1.value |

Note on breaker paths: the hub also publishes a deeper path breakers/children/HIFI/children/HIFI/state, but that is a retained MQTT message that does not update with live state. Always read from sailsense.breakers.{Name}.state.

String payloads are coerced to native types: "True"/"False" become booleans, numeric strings become numbers, and JSON blobs are parsed into objects.

Subscribed topics

• batteries/# — battery voltage, current, percentage, remaining capacity, alerts
• tanks/# — tank levels (%, L, US gal) and alerts
• actions/# — switch/light states and dimmer steps
• breakers/# — breaker on/off states
• Hub/# — GPS, wind, depth, IMU, Wi-Fi, Zigbee, and telematic data
• powernet/# — power rail voltmeters, analog inputs, and output states
• ui_config/# — Hub UI configuration blobs

Dashboard

This package includes a built-in web dashboard, served by Signal K at:

http://<signalk-host>/signalk-sailsense/

The dashboard has four tabs:

| Tab | Shows | |---|---| | Power | Battery bank voltage, current, and state of charge (dynamically discovered) | | Tanks | PORT/STBD fill gauges for fresh water, fuel, and blackwater with litre readouts | | Breakers | All 15 circuit breakers with live on/off indicators | | Lights & Pumps | Nacelle, exterior, and cabin light states; bilge and water pump states |

Data updates in real time via WebSocket with a 3-second REST polling fallback. No installation or build step required — it is a single HTML file bundled with the plugin.

Tabs can be deep-linked via URL hash: #power, #tanks, #breakers, #lights.

Browser compatibility

The dashboard is compatible with Chrome 70+, including the embedded Chromium browser on B&G Zeus 3 and similar Navico MFDs. No polyfills are required — the code avoids all JS and CSS features introduced after Chrome 70.

Authentication on MFDs

MFDs have no Signal K session cookie, so if Signal K has authentication enabled and Allow Read-Only Access is disabled, the dashboard will display an error rather than silently showing empty panels.

Two ways to fix this:

• Simplest: in Signal K admin go to Security and enable Allow Read-Only Access. This allows unauthenticated reads on a private boat LAN.
• Token-based: configure a JWT token in the signalk-navico-embedder plugin. The embedder injects the token into every proxied request and into the page as window.SK_TOKEN, which the dashboard picks up automatically.

Hardware reference

See DEVICES.md for a full map of breakers, lights, pumps, tanks, and Powerail outputs specific to the SailSense system.

License

MIT

Luke's development cheatsheet

npm link /Users/lukeescude/Code/signalk-navico-embedder && npm link /Users/lukeescude/Code/signalk-sailsense && signalk-server