AN OPEN SMART-BOAT BUILDING KIT IN DEVELOPMENT
Charts, instruments, music and sonar: shared services aboard, custom interfaces running on the devices. Refitting Number Five is becoming a building kit we can change, extend and share.
Developed with AI. Built on open foundations. With room for your ideas.
Choose the hardware. For your budget and installation.
Shape the controls. Local and native on Android.
Extend the system. Through shared interfaces.
01 / WHAT THE IDEA LOOKS LIKE
The benefit lives between the apps: the display can change while the service remains. We control the design and describe the data paths. These examples show existing work and its next steps.
Native chart rendering, our own route and layer controls, an inexpensive display. The device GPU draws locally. HTTP and WebSocket connect shared services. This opens up design choices a price comparison alone cannot describe.
Go to the device demonstration ↓Chart development and open items
Music playback and sound processing run in the independent Pi module. The native interface controls the service: volume, sound and outputs belong together. Another client can build on that foundation instead of creating a second playback system.
From Spotify to our own audio module
An examined Venterior fishfinder, a Pico and our own processing: real echoes become visible in the Android interface and depth can be shared with other services. The specific test setup is documented; trials aboard are still ahead.
Explore the sonar build
SEE FOR YOURSELF
Clips play only on request and run at original speed. A screen recording shows controls and data flow; it is not a separate performance measurement.
32 seconds from the native HELM app on a physical Lumina: the live echogram and A-scope on the existing test setup. The A-scope view is hidden and shown again.
2026-11-01 · Lumina K706 · Android 10 · 2000 × 1200 (recording: 1280 × 768) · HELM 206 · 0.8.134-sonar-start-depth-controls · Original speed, silent
32 seconds from the native HELM app on a physical Lumina: the live echogram and A-scope on the existing test setup. The A-scope view is hidden and shown again.
Test setup, not acceptance aboard a boat or absolute depth calibration. Temperature is not shown. Other header telemetry is labelled as simulated. Recording frame rate is not an app or GPU measurement.
Captions as text ↓An uncut sequence on the physical Lumina: appearance, schematic style preview, chart content and the existing chart library. Every screen comes from the installed native MAP app.
2026-11-01 · Lumina K706 · Android 10 · 2000 × 1200 (recording: 1280 × 768) · MAP 110 · 0.5.42-memory-budget-v8 · Original speed, silent
An uncut sequence on the physical Lumina: appearance, schematic style preview, chart content and the existing chart library. Every screen comes from the installed native MAP app.
Supplementary UI tour; not proof of chart panning, zooming, rotation or rendering speed. The schematic style preview is not a rendered nautical chart. No settings were applied.
Captions as text ↓The planned pan, zoom and rotate chart clip remains open: installed MAP 110 currently holds only the South Africa collection, whose public image permission is unresolved. The two-client audio demonstration currently lacks an available playback source. Neither is replaced with a simulation.
02 / WHY IT BELONGS TOGETHER
Sensors and devices supply data. Services handle their specific tasks. Today’s Android interface renders locally and accesses them over the boat network. A display can look different without losing the shared foundation.
A new control position, another sensor, an additional application: each needs suitable integration, without requiring a completely new system each time.
Three ways to extend it03 / THE FREEDOM BEHIND IT
Our examined Luminas cost €75 per display according to my own report. Another device needs a suitable profile and a test. The idea remains: controls and services work together while hardware can be chosen.
Helm, second seat or a dedicated control: shared services give the extension somewhere to connect. A wireless button still needs a specific radio link, power and acknowledgement mechanism.
Day, night, instruments, music and charts can share a control environment of our choosing. iOS would be another client requiring development; today’s main interfaces are native Android apps.
04 / THE PATH WAS NOT STRAIGHT
Android 14 turned out to be Android 10. Charts did not simply fit into memory. An attractive control was not yet smooth to use. And a finished design was far from an installation. Those detours created the shared foundation.
The workshop story connects the decisions: what we wanted, what failed, what we changed and what became useful. Software, hardware and installation developed in parallel.
Read the full story75 EUROS IS THE START
A €75 display makes getting started interesting. An installed boat system includes more. We show its components rather than counting unknown costs as zero. Updated: 1 November 2026.
| Component | What it includes | Evidenced price status |
|---|---|---|
| Display | One Lumina/K706; €75 according to my own purchase report. Count a second device separately. | €75 · owner report |
| Pi and storage | Raspberry Pi 5, 8 GB; cooling enclosure and 64 GB microSD are documented in the inventory. | Purchase prices not recorded |
| Power | DC converters, fuses, wiring and power for the chosen devices. | Setup-dependent · open |
| Audio | USB 5.1 sound card documented; amplifier, speakers and acoustic setup depend on the boat. | No evidenced package price |
| Sonar and sensors | Examined fishfinder, Pico, adapters and sensors for the chosen configuration. | Purchase prices not recorded |
| Enclosures and fabrication | Count print material, screws, boards, connectors, printing and soldering separately. | Material + fabrication open |
| Installation and shipping | Installation, cable routing, local sourcing, shipping and possible import costs. | Country- and boat-dependent |
Inventory records confirm core components but contain no reliable purchase-price fields for them. Labour, shipping and imports remain open. We therefore give neither a misleading total nor a blanket comparison with a finished plotter.
Recorded inventory includes a four-way RCA connector at R24.38, a fuse holder at R18.57 and an HW64 converter at R72.10, each excluding VAT. These historical individual values were checked on 1 November; that does not confirm purchase date, current availability or shipping. They do not automatically all belong in the same variant.
Venterior V15-2 print preparation estimates around 338 g of PETG including supports and a test piece. This is a slicer estimate, not measured consumption or a fabrication price. Alternatives must match function, dimensions and connections. Local suppliers and assembled modules are particularly useful contributions.
Inspect cost and source references05 / YOUR STARTING POINT
You do not need to refit an entire boat. Take the part you need, and show us what you make of it.
Making a boat system out of good individual components.
The important values at a glance. An interface made for the boat.
The Pi plays the music. The helm keeps the controls simple.
Large, affordable and usable: what we can get out of Android displays.
Our own chart interface on established foundations. With routes that belong to the system.
Converting our own vector data into other chart formats. A path is open; the work continues.
From an inexpensive handheld device to our own echo capture and display.
Connecting existing boat equipment instead of replacing everything.
Often the hard part is physical: printing, soldering, wiring and mounting.
OPEN SOURCES · OPEN INVITATION
Code, circuits, designs and experience are here to build on. Help test, find local parts, print a better mount or offer installation and fabrication. A useful workshop contribution matters as much as a new app.