NMEA 0183 and 2000 multiplexer for Raspberry Pi

[goboatingnow]

I’m a retired embedded systems engineer with a lot of can bus experience and I have written nmea 2000 code

I am currently building a few 2K projects for my boat as I use a LIN network to collect current /voltage data from around the boat and I’m going to send selective PGNs to the 2K network.

Optically isolating either the can or nmea0183 is largely a waste of time as on a boat where all the devices are sharing the same power and ground sources , robust input protection is needed but isolation isn’t

In most situations can bus needs a common ground to ensure the rather restricted relative voltage levels are maintained , again isolated can bus is possible but unnecessary

Be aware that nmea 2000 is effectively a closed protocol , only parts of it have been reversed engineered

I have full pcb cad , and surface mount oven etc , if I can be of help let me know, I’m not in the US but that hardly matters. I do have access to the full component supply chain etc.

[akopac]

Check this out. https://www.gedad.de/shop/gecos-wire...ct-15562399022

[pfaguiar]

Originally Posted by goboatingnow

I am currently building a few 2K projects for my boat as I use a LIN network to collect current /voltage data from around the boat and I’m going to send selective PGNs to the 2K network.

I am struggling with a LIN bus on my boat, and perhaps you have any pointers for me.

I have a Scheiber module 7 multiplexer that received analog inputs from fuel, water and batteries, and was trying to inject that data into NMEA 2000 bus.

Do you by any chance had seen any gateway or device that would allow me to do that?

Thanks in advance for your help!

[belizesailor]

Take a look at YakBitz, they have a bunch of variations on their products. Low cost. Good support too.

http://www.yakbitz.com/

[JTeixeiraPOR]

Originally Posted by WhiteHill

Me too. Please include me in any future advances. Thanks.

Me too! Please let me know as soon as you "put your hands on the project"!

[Ruiner]

Nice thread, i just stumbled on it.

I am too building IoT gateway for my yacht. I had old Brookhouse NMEA/Seatalk USB multiplexer lying around and I have CanBUS interface on Rasberry Gasblender HAT that I use so I just pieced it together from those. Just started working on it so It is very much work in progress. I plan to switch to Beagleboard Green as soon I get around to it. Raspberry sucks a lot of energy and can not sleep so even in idle it draws "huge" amount of electricity. As I want to run purely on solar, that is not optimal. Raspberry draws 3-4W even with zero load and Beagleboard should do maybe 1/10th of that. Making dedicated carrier board for that with NMEA0183 as well would be elegant. I have also two Victron MPPT chargers there connected with VE.Direct cables to Raspi.

Software side I make simple NMEA0183/seatalk listener that converts messages to MQTT. Only tested it with old tridata unit so it is still just a template implementation. I will change that so that it will push data directly to Fiware Context broker via IoT Agent. Data is then available to be visualised with Grafana. My vision is to make 11"-13" E-Ink plotter/display for helm based on OpenCPN where that data can be used.

Here is a simple serial reader for NMEA multiplexer I pieced together if that is of any use to anyone. It currently only understands two sentence indentifiers but as soon as I get to my yacht I will add more:
https://github.com/AbyssCoreInc/NMEA_Adapter