Maik
What is it?
BoatOpenIO is a modular 4-board hardware platform for boats built with analog instruments. It connects legacy VDO sensors (oil pressure, temperature, tank, RPM, battery) to modern systems via MQTT and Signal K — without replacing a single sensor or losing the original analog gauges.
The system sits in parallel to the existing instruments. Your VDO gauges keep working exactly as before. At the same time, all values are available digitally — compatible with BoatOS, OpenPlotter, AvNav, OpenCPN and any chartplotter that speaks NMEA2000 (in development).
Hardware — v2
Four separate PCBs connected via IDC ribbon cable:
- Input Board (110×46mm) — 16 screw terminals, hardware protection on every channel (Bourns R_Pack08 + SP0503BAHTG Zener arrays)
- Main Board (90×60mm) — CD74HC4067 MUX, ADS1115, MPU6050, AMS1117 — all socketed
- ESP32 Adapter Board (80×30mm) — swappable for different ESP32 variants
- VCC Distribution Board (20×80mm)
8 output channels prepared on the Main Board for relays, pumps, heating and horn — same swappable mini board concept as the inputs.
Mini Boards
Each of the 16 input channels gets a swappable mini board for signal conditioning:
- VT — voltage divider (12V VDO sensors → 3.3V)
- PU/PD — pull-up / pull-down
- ST — Schmitt trigger (magnetic pickup, RPM)
- ISP — impulse board (Arduino/ESP01 for RPM counting)
- OPT — optocoupler (galvanic isolation)
- DIR — direct (3.3V signals)
Firmware
ESP32, MQTT, WiFiManager, OTA, bilingual Web-UI (DE/EN). MQTT topics configurable per channel — default boat/io/<sensor> or one click for the correct Signal K path.
Why?
Commercial marine IO gateways cost several hundred euros and are closed systems. BoatOpenIO costs a fraction — and everything is open source, documented with all the failures included. No polished tutorials. Just honest engineering.
Get the PCB set: 🛒 https://www.tindie.com/products/bigbrainlabs/boatopenio-v2-pcb-set-4-boards/
Support the project:
❤️ https://www.patreon.com/cw/logbook_without_posing
⭐ https://github.com/sponsors/bigbrainlabs
Part of the "Logbook Without Posing" book series.
📖 DE: https://amzn.to/4e5swN6
📖 EN: https://amzn.to/4vxWr5W
MHefny
Peter Buchegger
chakavin
Dariush Salami
NMEA2000 coming to BoatOpenIO?
Three MCP2515 CAN-Bus modules arrived. The idea: analog VDO sensors in, NMEA2000 out — directly compatible with every Garmin, Raymarine or Simrad chartplotter on the market.
Lab test planned: two modules, two ESP32s, one sends, one receives. If that works, the firmware work begins.
No promises, no timeline — but the hardware is on the bench. Who's interested?