Free & open-source · Signal K · Raspberry Pi

Your boat's instruments,
on a €50 screen you build.

Wind, navigation, batteries, solar, tanks, anchor watch with phone alarms, AIS collision monitoring, and full sailing-performance analysis — one clean panel, running on a Raspberry Pi in your nav station. No subscription. No cloud you don't control.

See the code
€150–250
Typical build
100%
Open source
24/7
Anchor & AIS watch
0
Subscriptions
The Oroboro dashboard on a nav-station tablet — wind rose, speed, depth, water tanks, house bank and solar readouts on a dark instrument panel
Live at anchor · Paros, Cyclades
The honest comparison

A Victron panel shows you Victron. This shows you the whole boat.

Victron's GX Touch is excellent — for Victron gear. But your wind, depth, heading, AIS, and tank senders live on the NMEA 2000 network, and the Cerbo barely speaks it. One Raspberry Pi reads everything — and costs a third as much.

Cerbo GX + GX Touch 50

  • Battery, solar, and Victron devices — beautifully
  • Limited NMEA 2000 — no real wind/depth/AIS dashboard
  • No anchor watch with phone alarms
  • No sailing-performance analysis
  • Closed ecosystem, fixed feature set
≈ €530–630 · electrical only

Oroboro Dashboard on a Pi

  • Wind, nav, depth, batteries, solar, tanks — one panel
  • Reads the entire NMEA 2000 network via Signal K
  • Anchor watch + AIS Guardian, alarms to your phone
  • Polar performance analyzer built in
  • Open source — change anything, owe nothing
≈ €150–250 · the whole boat
The main dashboard

Your whole boat, at a glance.

One screen brings together everything your instruments and Victron system already know — true and apparent wind on a live rose, speed, depth and water temperature, house-bank state of charge with power flowing in and out, solar yield panel by panel, and tank levels. No flipping between apps or squinting at four separate gauges: the numbers that matter are laid out the way a sailor actually reads them, updating live. It runs full-screen at the nav station, on a cockpit tablet, or on your phone — same panel, everywhere.

Wind & navigationBatteries & solarTanksLive, no refresh
The Oroboro main dashboard on a phone — wind rose, speed, depth, house bank, solar and tanks on one dark panel
Anchor watch

Sleep easier at anchor.

Drop the hook, set an allowed circle — or a directional sector for a tight spot — and the Pi watches your swing all night. Drift outside the zone and your phone alarms, sent straight from the boat whether or not you're aboard. Because the alarm runs on the Pi, not the browser, it reaches you ashore at the taverna too.

GPS swing trackPushover alarmsWorks offline
Anchor watch on a phone — allowed zone circle, boat swing track, and nearby AIS vessels on the map
Guardian · AIS proximity watch

A witness that never sleeps.

Guardian watches every AIS-equipped vessel around you, day and night. A boat enters your zone — or drags down onto you at 3 a.m. — and it records a full breadcrumb track, closest approach, and top speed, then alarms your phone. Every encounter is saved as a timestamped incident report you can hand to a harbourmaster or insurer. Nearby boats even leave visible swing-arcs, so you see how the whole anchorage lies.

24/7 on the PiIncident reportsClosing alarms
Guardian push notifications on a phone — vessel-in-zone and anchor-dragging alerts with distance and speed
Polar performance

Sail closer to your boat's best.

Every sail is logged and scored against a VPP target polar for your hull. See live VMG versus target, a colour-coded performance heat-map of your track — green where you're sailing well, red where there's speed left on the table — and your personal-best envelope building up over the season. It turns a day on the water into something you can actually learn from.

VPP target polarTrack heat-mapPersonal bests
Polar performance screen — VPP polar diagram with live wind and VMG readouts Track heat-map — the sailed route coloured by percentage of polar target
One panel, any screen

Nav station, cockpit tablet, or the phone in your pocket.

It's a web dashboard, so it runs anywhere with a browser — a fixed screen at the chart table, a tablet in the cockpit, your phone at anchor. Same live data, no app to install, shared across the whole crew.

The Oroboro dashboard shown at an angle on an iPhone — wind rose, speed, depth, battery and solar
Everything on one panel

Built for the way you actually sail.

Every instrument your NMEA 2000 network already produces, plus the tools cruisers wish came standard.

Wind & nav

True and apparent wind on a clean rose, heading, SOG, COG, depth, and water temperature — the core six at a glance.

Batteries & solar

State of charge, net power in or out, voltage, and solar yield — pulled from Victron over the same network.

Tanks

Fresh water, fuel, and waste levels front and centre — with the sender options spelled out for boats that lack them.

Anchor watch

Circular or directional zones, live swing track, and phone alarms that fire from the Pi even when you're ashore.

Guardian AIS

24/7 collision and drag watch on other vessels, with breadcrumb tracks and exportable incident reports.

Polar performance

A VPP-based analyzer that scores your sailing against target speeds, logs personal bests, and shows a performance heat-map of your track.

Built at sea, not in an office
I wanted to see my whole boat on one screen — wind, batteries, the anchor holding through the night — without buying a closed box that only spoke to half of it. So I built it on a Raspberry Pi, and now it runs every day aboard Oroboro.
Francesco · Skipper, S/V Oroboro · Leopard 40 · Cape Town → Greece
Your nav station, upgraded

The whole boat, on one screen you own.

Free, open source, and documented step by step — from which HAT to buy to the final git push. If you can follow a recipe, you can build this.

Browse the repo
CC BY-NC 4.0 · never your only anchor watch or navigation source
The build guide

From a bare Pi to a live panel.

Every step, in order — hardware, wiring, software, and deploy. New to Raspberry Pis and Signal K? This is written for you. The full README is the deep reference; this is the friendly path through it.

Plan · 01

What it costs

Approximate street prices, mid-2026 — they drift, so treat them as ballparks. The core electronics come in well under a Victron panel that does less.

ItemApprox.Needed?
Raspberry Pi 4 (4 GB) or Pi 5€60–90Yes
Quality microSD card, 32 GB+€10Yes
12 V → 5 V USB-C converter, 3 A+€10–20Yes
NMEA 2000 CAN HAT (MacArthur / PiCAN-M / Waveshare)€20–90Yes*
4G/LTE WiFi router + data SIM€50–150For remote alarms
Cockpit HDMI touchscreen, 7–9″€60–120Optional
Typical core build€150–250

*Or a USB gateway (Actisense NGT-1, Yacht Devices) at €170–200 instead of the HAT. All software — OpenPlotter, Signal K, InfluxDB, Grafana, Tailscale, this dashboard — is free.

Plan · 02

The parts list

At minimum you need three things: a Raspberry Pi (the computer), a way to power it from the boat's 12 V, and an interface to your instrument network. Everything else — touchscreen, 4G router, Victron cables — extends what you can see and do.

The single decision that trips people up is the instrument interface, because it depends on how old your boat's electronics are. That's the next step.

Wire · 03

NMEA 2000 — you need a CAN HAT

The Raspberry Pi has no marine-network port of its own, so you add a small board. For a modern boat (roughly 2008 onward — Raymarine SeaTalkng, Garmin, B&G, Simrad) that board is a CAN bus HAT.

Common mix-up · CAN vs RS485

NMEA 2000 runs on the CAN bus — so you need a CAN HAT, not an RS485 board. RS485/RS422 is the physical layer of the older NMEA 0183 and Seatalk standards. Wiring an RS485 adapter to a NMEA 2000 backbone will not work: wrong signalling. If in doubt and your instruments are post-2008, you want a CAN HAT.

The wiring itself is two data wires from the backbone into the HAT:

# NMEA 2000 drop cable → CAN HAT
white  →  CAN-H
blue   →  CAN-L
# leave red/black (power) disconnected — the Pi powers the HAT

Older boat (pre-2008 NMEA 0183 or Seatalk1)? Then instead of a CAN HAT you use a USB-to-RS422/RS485 adapter (~€10–25), and OpenPlotter reads the 0183 sentences. The MacArthur HAT handles both worlds if you're mixed.

Wire · 04

How everything connects

The shape of the system, start to finish:

boat instruments ─┐
Victron gear ─────┤→ NMEA 2000 backbone →  CAN HAT  →  Raspberry Pi
AIS / GPS ────────┘                                      │
                                              Signal K (reads it all)
                                                         │
                                          ┌──────────────┼──────────────┐
                                     this dashboard   InfluxDB       anchor-api
                                       (the panel)   +  Grafana      (24/7 watch)
                                                     (history)

Signal K is the translator: it reads every device on the backbone and republishes it in one common format. The dashboard, the history database, and the anchor/AIS watchdog all read from Signal K. A small WiFi router ties it together so your phone and cockpit tablet see the same panel.

Software · 05

Install OpenPlotter

OpenPlotter is a ready-made Raspberry Pi image with Signal K already aboard — the fastest way to a working marine server. Flash it to the microSD card with Raspberry Pi Imager, boot the Pi, and you have Signal K running.

  • Download OpenPlotter and flash it to the SD card
  • Boot the Pi, connect it to your WiFi router
  • Open Signal K's admin panel in a browser at the Pi's address, port 3000
  • Add your CAN (or 0183) connection so Signal K starts seeing instruments

When the Signal K Data Browser shows wind, depth, and position updating, your hardware half is done.

Software · 06

Give the Pi a static IP

So the dashboard always finds the Pi at the same address, pin it down on your router (or in the Pi's network settings). Everything from here assumes a fixed address like 192.168.1.238 — use whatever your network gives you and keep it consistent.

Software · 07

Connect your Victron system

To see batteries and solar, bridge Victron into Signal K. Three paths, depending on your gear:

  • Already have a Cerbo/GX? Enable its MQTT output and point Signal K at it.
  • No GX device? Run Venus OS on a second small Pi with VE.Direct-USB cables — the open-source route to the same data.
  • Direct? VE.Direct-to-USB straight into the OpenPlotter Pi for simpler systems.

You don't need to buy a Cerbo just for this — the README's "you don't need a Cerbo" section walks through each path in detail.

Software · 08

Deploy the dashboard files

The dashboard is a set of HTML files that Signal K serves. Put them in Signal K's public folder and open them in a browser. The repo's README gives the exact copy commands; the essence:

# on the Pi — fetch each page into Signal K's public folder
sudo wget -O /usr/lib/node_modules/signalk-server/public/oroboro.html \
  https://raw.githubusercontent.com/fpugliano/oroboro-dashboard/main/oroboro.html

Repeat for each page — anchor.html, polar.html, settings.html, and the logo. Then open http://YOUR-PI-IP:3000/oroboro.html and the panel appears.

Software · 09

Anchor & Guardian background service

The anchor watch and the AIS Guardian run as a small always-on service on the Pi — anchor-api.js — so alarms reach your phone even when no browser is open. Install it to /home/pi/anchor-api/ and register it with systemd so it starts on boot and restarts itself.

# after copying anchor-api.js to the Pi
sudo systemctl restart anchor-api
sudo systemctl status anchor-api    # expect: active (running)

This service is what makes the safety features real: it watches your swing and every AIS vessel around you 24/7, and pushes alarms whether you're at the helm, asleep, or ashore.

Software · 10

History & polar performance

For graphs over time and the sailing-performance analyzer, add InfluxDB (stores the data) and Grafana (draws the history graphs). Signal K's InfluxDB plugin logs everything; Grafana visualises it; the polar page reads back your speed-vs-wind history to score your sailing. The README covers the tokens and settings step by step.

Software · 11

Configure your boat's specifics

One file, config.js, holds your boat's details — network addresses, your Pushover keys, your polar targets. It stays on the Pi and never goes into the public repo, so your secrets are yours. Set it once and the whole dashboard picks it up.

Software · 12

Phone alarms with Pushover

Anchor-drag and Guardian alarms reach your phone via Pushover — a one-time small purchase, no subscription. Create an account, paste your user and API keys into the Pi's config, and the background service does the rest. Because the alarm is sent from the Pi, it works as long as the Pi has internet — even with your phone locked and every browser closed.

Live · 13

See it from anywhere

Add Tailscale (free tier) and the Pi joins a private network you can reach from your phone anywhere with signal — no port-forwarding, no exposed ports. Check your batteries from the beach, watch the anchor hold from dinner ashore. The anchor and Guardian alarms run independently on the Pi regardless, so they protect the boat whether or not you're connected.

Live · 14

You're done — go sailing

That's the whole build: a Raspberry Pi reading your entire boat, a clean panel on any screen, a 24/7 anchor and collision watch in your pocket, and performance analysis that turns every sail into data. All of it yours, all of it free, none of it locked to anyone's cloud.

Hit a snag, or built something you're proud of? Open an issue on GitHub — the project is alive and the fleet is growing.

Get the code →