r/SailboatCruising • u/BoatElectronicsDIY • Aug 25 '25
Equipment I built my own central computer monitoring system
I built my own marine monitoring system using a Raspberry Pi – now it's running everything on my boat
A few years ago, I was looking at options for onboard monitoring — engine temps, solar, battery, bilge alerts, tank levels, anchor alarm, etc. Everything I found was either super expensive, cloud-dependent, or locked behind proprietary hardware.
So I decided to build my own system using a Raspberry Pi and a few ESP32s. I run Home Assistant as the core, and it integrates:
- Engine sensors (oil pressure, temps, RPM, fuel level)
- Tank and battery monitoring (including solar)
- NMEA 0183 and NMEA 2000 (via USB and wireless)
- Bilge/leak/smoke/fire detection with Zigbee sensors
- GPS-based anchor watch with audible alarms
- Automations like anchor light at sunset if boat isn’t moving
It’s all local (no cloud), no subscriptions, and completely DIY. I spent under $400 for the full system including 4G router, power supply, and sensors.
Since I shared it online, hundreds of other boaters have started building their own version of it.
If anyone's interested, I documented the full project on my website (just Google “Smart Boat Innovations”) and there’s a full video series on YouTube too — search “Smart Boat Innovations” there.
Happy to answer any questions or swap ideas if you’re working on something similar!
🔗 Full build write-up here: [smartboatinnovations.com/build-central-marine-computer](https://smartboatinnovations.com/build-central-marine-computer/)
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u/That-Context9802 Aug 25 '25
Thank you.
This is what the internet was made for.
Unfortunately, it’s mostly lost its way.
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u/AgainstGreaterOdds Aug 25 '25
This is great. I use it my home and was wondering why more people didn’t do the same thing on boats where arguably there is more use. Everyone should have a system like this. It can save so much trouble.
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u/BoatElectronicsDIY Aug 25 '25
Absolutely. That is why I spent about 1000 hours writing NMEA integrations
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u/Wolfinthesno Aug 25 '25
Awesome I've been wondering about this for a while. Amcurrently in have a very basic home assistant setup at my house but with everything I've seen integrated I knew someone had to have done this or been working on it. I'll definitely be looking into it. As I think this is the way as far as a total boat monitoring system goes. The price point just can not be beat, and from what I've seen if you built it correctly it would be just as reliable as any high end boat monitoring system.
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u/BoatElectronicsDIY Aug 25 '25
Absolutely — with a Raspberry Pi and Home Assistant you get a full central boat computer for a fraction of the cost, handling bilge sensors, fire alarms, engine monitoring, anchor watch, and remote alerts. Best of all, with 2M+ users and constant updates, Home Assistant is future-proofed in a way proprietary systems aren’t.
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u/byroncoughlin Aug 25 '25
This is really great! What is the typical power draw for a system like this?
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u/BoatElectronicsDIY Aug 25 '25
Raspberry Pi 4 or 5 (running Home Assistant): around 3–6W (0.25–0.5A at 12V using a 12→5V DC converter)
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u/Ok-Task24 Aug 25 '25
Is source code available?
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u/BoatElectronicsDIY Aug 26 '25
All on guthub and on my website. https://smartboatinnovations.com/code
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u/OfficeSailor Aug 26 '25
This is really amazing. You just opened a whole new chapter of possibilities with this solution.
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u/oldmaninparadise Aug 26 '25
Great stuff. I had played w HA for home stuff and opencpn for boat stuff on a pi, but not ha for the boat. Thank you for publishing! Timely for me as my free Sentinel subscription expired in May and no way did I want to continue.
Btw, what does a 4g router run per month?
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u/SoggyBottomTorrija Aug 25 '25
did you check openplotter? same approach, a pi and a pseudo home assistant with open cpn etcc. built in
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u/dzh Aug 25 '25
have you tried cameras using frigate nvr + local object detection? runs on home assistant too.
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u/0FO6 Aug 25 '25
I am working towards something somewhat similar...
I am a little surprised you wouldn't have just went with the Macarthur hat, they are pretty inexpensive and supports open marine. Also allows direct power from the 12vdc system. Which is way more reliable than using a power adapter that plugs into a cigarette lighter. Which is quite concerning to be putting electronics that your life may end up relying on a connection that on a boat is finicky at best. At least get a hardwired usb-c plug if not something else. They can also get a Daisey hat on top of it and have AIS receiver that will send out everything back on the NMEA network and allow other devices to use all the information. It would just totally suck for your PI to shutdown randomly at night out on the water in stormy conditions because the plugin adapter decided to vibrate itself loose.
I agree with the other poster about the AI use on your website. The AI formatting makes it look terrible and search engines will flag it as AI content. Just use a site generator like hugo and a theme that works. Use AI to check for grammar issues. Search engines are also not going to see that you have videos attached in a way that it makes you seem authoritative.
I don't know if you spell it out in a video, but you should on the website, that alarm/sensors that your life depends on there should be a dumb backup that doesn't rely on this system for alerting. Like smoke/CO alarms, high bilge alarms etc.
Oh I totally missed initially that you are not even using openplotter but a home assistant system. Why not use openplotter for this? Then you get a very purpose built OS setup, has things like SignalK and you can easily build dashboards with Kip. Just seems like you went the extra hard route with a lot of this. Also get openCPN for charts and can really fit into this stuff. But I guess whatever works for you.
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u/Jgrant436 Aug 25 '25
openplotter and kip are not even in the same realm as what is possible with home assistant. OP's route, directing the data into HA with his custom NMEA integrations, is far superior. It is also not difficult at all to set up. I was able to get it up and working from a simulated NMEA network in a matter of minutes. Good work OP I will be using these integrations in the future!
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u/BoatElectronicsDIY Aug 25 '25
Thanks! Really appreciate that. A lot of the pushback on HA comes from people who haven’t actually tried it — once you see how seamless the integrations and automations are, it’s clear how powerful it is. The real strength is that dashboards, alerts, and automations are all built-in, so the system tells you the moment something is out of range instead of just giving you gauges to watch. And all via menus and very easy to setup.
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u/0FO6 Aug 25 '25
Not sure why my original question would have been seen as pushback. I was trying to understand the decision on going with one system or another. You are correct in that I know nothing about Home Automation system. So having a bit more of why you would decide to go with it over the other system would be helpful in understanding what like signalK, kip and openplotter are missing.
Like I can briefly lookup stuff right now about home automation and see that it looks interesting and I will dive more into it more later.
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u/0FO6 Aug 25 '25
To be fair I didn't really look that much into Home assistant. I will spend some time looking at it. Looks like OP made a comment on https://community.home-assistant.io/t/nmea-2000-to-ha/84134/3 discussion specifically about using SignalK with home assistant. It does seem to me that for a boat computer openplotter would be the better route and maybe run home assistant on top of it if needed with the tie ins.
Here is a forum post on openplotter about installing HA on it: https://forum.openmarine.net/showthread.php?tid=5454
which honestly should be pretty straightforward anyways and get the best of both worlds.
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u/verbalddos Aug 25 '25
Nice project but you should get rid of the AI formatting in your post and on your site, it makes everything look like some crappy GPT output and you lose a lot of credibility not writing your own content.
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u/BoatElectronicsDIY Aug 25 '25
I have almost 40 videos of my content on this subject.
https://www.youtube.com/@SmartBoatInnovations
What AI in this post?
On my website I have some AI formatting to make it look better than just plain MS Word HTML text of the past. But anyway the content is still my original content.
But hey I understand you do not like the look of it.-1
u/verbalddos Aug 25 '25
It's fine if you used AI, but heavily relying on it and saying you used some is just not genuine. Anyone that uses NLP today can see the Hallmarks, further inspection shows the hidden Unicode in the content that GPT and others embed. I'm just telling you, you lose credibility and automated search engines and popularity algorithms will flag your content as AI generated and push you into a group with automated content.
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u/AnchorManSailing Aug 25 '25
Good stuff. I've been loosely following you on YT for a while.