A modular, Arduino-powered 12V power distribution and control system designed for boats and other off-grid applications.
SmartFuseBox combines fused relays, quick-connect aviation plugs, and Arduino-based monitoring into a single 3D-printed enclosure — with a built-in security twist.
I bought a mid-80s boat and wanted to give it a modern electrical upgrade.
The original wiring was dated, messy, and lacked any real security. Since the boat is kept in a marina, theft was also a concern.
SmartFuseBox was born out of the need for:
- Reliable 12V power distribution for navigation lights, bilge pumps, and other onboard systems.
- Quick-connect modularity so I can easily add/remove systems with aviation connectors.
- Integrated monitoring via Arduino sensors (temperature, humidity, light, etc.).
- Basic security through a “poor man’s immobiliser” — the control unit must return a valid 12V feed before the system powers up.
- 8 fused relays for distributing 12V power safely.
- Aviation connectors for quick, reliable connections to onboard systems.
- Arduino integration for both control and sensor inputs.
- Nextion display + Arduino Mega in the control unit for user interface and system logic.
- Immobiliser-style security:
- Main 12V input passes through the control unit.
- The control unit must return a valid 12V feed to enable the system.
- 3D-printed enclosure for a compact, customizable housing.
- 8 × fused relays
- Arduino (for relay control and sensor handling)
- Multiple aviation connectors (12V systems + sensor inputs)
- Connected to control unit via 7-wire harness:
- 12V in
- 12V out (return feed)
- Ground
- 5V out
- TX / RX (serial comms)
- Spare line
- Arduino Mega
- Nextion touchscreen display
- Handles user interface, relay control, and immobiliser logic
- Returns 12V feed to enable the fuse box
- Marine upgrades: modernize older boats with modular, safe wiring.
- Off-grid projects: camper vans, RVs, or solar-powered cabins.
- DIY automation: any 12V system needing fused relay control + monitoring.
(Add photos of the 3D-printed enclosure, wiring, and display here once available.)
- Add CAN bus or RS485 support for longer cable runs.
- Expand sensor integration (GPS, water level, etc.).
- Publish STL files for the 3D-printed enclosure.
- Provide example Arduino sketches for both units.
Please read the SETUP.md file for detailed instructions on setting up the Arduino code.
Contributions, ideas, and improvements are welcome!
If you’ve built something similar or adapted SmartFuseBox for your own project, feel free to open an issue or share your setup.
GNU General Public License v3.0 (GPLv3) — see LICENSE for details.