Transmit NMEA data to shore

[swabie]

Hi all, I know there are several devices/apps etc that can pick up NMEA/Seatalk data via WiFi and display it on an iOS/Android device on the boat, but I am looking for something a bit different....

I would like to be able to transmit boat instrumentation data to a location OFF the boat (via 4G connection, etc) where it could be remotely viewed via PC, etc.

Primary usage would be for regatta telemetry for the public.

Has anyone head of any solutions like this? Or any regatta telemetry solutions for that matter (other than basic GPS/SoG tracking apps)?

Ideally it would just be an app that is run on an Android phone as a re-transmitter, but I'm up for all ideas! (Smaller the footprint/power requirement the better)

Thanks

[CaptTom]

Sounds like you're looking for an underway internet connection.

Simple; cell network near shore, satellite offshore. Not really any other options right now.

Maybe the hams have some data link options, but my guess is the bandwidth will be too low for NMEA data. Likewise, cell and especially satellite data costs are going to be pretty high.

[sveinung]

Nmea 2000 is just 250 kbit/s, and with compression you're probably looking at a fraction of that so not that much of a challenge for a mobile connection. If you only forward the nmea sentences you care about the data could be negligible.
Could've been an interesting to look at if you did the hardware part for nmea connector to micro USB on a phone!

[swabie]

Thanks for the replies. Not (too) concerned about bandwith currently due to proximity to cell service, but compression is always good!

Mostly interested in seeing if there is any off the shelf application or open source project we could work off that would have the basic framework for taking the NMEA data and sending it as a data stream off the boat, and software for receiving/displaying said data over TCP/UDP

NMEA data -> android/linux/pc transmitter software -> PC receiver software (via TCP/UDP) -> graphic rendering

[sveinung]

I didn't find anything for off the shelf, but I got a bit interested so I ordered a CAN bus USB dongle. I'm an Android software engineer so figured it could be a fun thing to look at. Seems pretty straight forward, but I wonder what's the cheapest way I can set up a live NMEA2000/SeatalkNG network at home that I can test on.
Buy a cheap used GPS and make a minimal nmea network powered by a 12V DC source?
What sentences/data are you most interested in? Wind speed info or speed/position/course?

[swabie]

Originally Posted by sveinung

I didn't find anything for off the shelf, but I got a bit interested so I ordered a CAN bus USB dongle. I'm an Android software engineer so figured it could be a fun thing to look at. Seems pretty straight forward, but I wonder what's the cheapest way I can set up a live NMEA2000/SeatalkNG network at home that I can test on.
Buy a cheap used GPS and make a minimal nmea network powered by a 12V DC source?
What sentences/data are you most interested in? Wind speed info or speed/position/course?

Very cool. Instead of hardware, maybe there is an NMEA emulator that could used for testing? Quick google search showed this: https://chrome.google.com/webstore/d...knlipcll?hl=en


Yes, re:data mostly wind speed/direction, boat speed/CoG, but I would be interested in seeing what data we could pull and make useful. (Rudder angle?) GPS position would likely be plotted via race tracker software like Kattack for now, but could foresee integrating it down the road. Interval wouldn't need to be realtime either, maybe .5 to 1 sec?

Would love to hear what your results are if you get something set up! I have no android development background myself, but happy to test, give feedback, etc.

[smac999]

moxa makes some interesting stuff. like some serial data to Ethernet stuff. maybe a moxa box on each end. would simply convert from serial over the net and the other side would convert back to serial? or maybe it only does across local network, not sure.

feed nmea 183 data on boat side to ethernet converter, then home end gets ethernet and converts back to serial, and feed that serial data (nmea 183) to a PC

https://manuauto.com/moxastore/index...ain_page=index

maybe contact them and ask about sending serial data across the internet.
I wouldn't bother brining up boats. that might just confuse them... if they can do it with basic serial data, it should work with nmea 183 data.

[continuouswave]

I can't offer any first-hand experience, but I think you could use a CELLULAR DATA MODEM on the vessel and another one on land.

The two cellular data modems would each need their own cellular service account. One modem would dial up the other. They would establish a connection, and data would be sent between them.

One manufacturer of cellular data modems is Muti-Tech Systems. They were a big player in the old wired-line data modem business. They now make cellular modems. See

https://www.digikey.com/en/product-h...ellular-modems

Their products look like they'd need a lot of integration. Here is a better integrated product:

This is an accessory kit for integration of the modem; cost $99.
https://nimbelink.com/Documentation/..._Datasheet.pdf

Then you need the actual modem; cost about $75.
https://nimbelink.com/Documentation/..._Datasheet.pdf

Or, just put LTE Modems on the boats and get an internet provider for them:

https://www.amazon.com/NETGEAR-Modem.../dp/B01MQRHQYT

[teppokurki]

Originally Posted by swabie

Has anyone head of any solutions like this? Or any regatta telemetry solutions for that matter (other than basic GPS/SoG tracking apps)?

A Signal K server setup on each boat can convert NMEA0183 and N2K data to Signal K format. Each server can be configured to send all or a selection of the data to a central cloud server.

Once on the cloud server people can connect to that and see data for all the boats, much like you can see vessels’ data over AIS, except here communications take place over cellular data and Internet.

The cloud server can naturally log all the data and with some additional modules provide data playback.

You can also pull other vessels’ data back to your local server and convert it to AIS formatted data that your plotter can display.

A Raspberry Pi is powerful enough for a local server.

You can also provide remote access to just your own boat’s SK data with for example ZeroTier, no cloud server required.

http://signalk.org/
https://github.com/SignalK/signalk-server-node/
http://slack-invite.signalk.org/

[svmobert]

Originally Posted by sveinung

Nmea 2000 is just 250 kbit/s, and with compression you're probably looking at a fraction of that so not that much of a challenge for a mobile connection. If you only forward the nmea sentences you care about the data could be negligible.
Could've been an interesting to look at if you did the hardware part for nmea connector to micro USB on a phone!

Compression notwithstanding, let's assume for a moment that you are actually streaming 250kbps over cellular to a cloud service or server.. if it's constant, that adds up to 80GB/month.. Even if you get 90% compression, that's 8GB/month. So while the realtime bandwidth is not technically an issue for cellular, the overall consumption could be a problem for you when it comes to billing.

Of course the amount of NMEA data flowing over an NMEA2000 bus is likely less than 250kbps, and possibly compressible, just keep the total amount of data consumption in mind in the planning. Most IOT devices are not transmitting GB's per month, they are almost always in the 10s of MB per month or less, and IOT focused cellular networks are designed with that in mind. You can certainly use T-Mobile, AT&T, Verizon standard plans, but data throughput on those plans will be throttled at some point with that amount of data flowing.

[Pizzazz]

Originally Posted by swabie

I would like to be able to transmit boat instrumentation data to a location OFF the boat (via 4G connection, etc) where it could be remotely viewed via PC, etc.

I am not aware of a solution that transmits nmea data to the internet. The closest solution I can imagine is the Wyze Cam, costs $24.99 on Amazon. You can pair it to a phone via Wifi and then view the video over the web. The bandwidth is variable, around 50 kbits/sec which is reasonable. I can imagine that live video would be more interesting to the public than some speed/wind/position data.

The other way to do it is via these bluetooth/wifi to serial converters. Each boat will need to have one installed, configured and connected to a serial port. This could also include Seatalk 1 data. Then you configure the device as a server and you need to have an app on the phone that takes the data and transmits it over the net, then you need a server on shore that can interpret and display the data. The bandwidth will be very low but it would be custom development, a pain to administer and configure - I would not bother.

Regards,
SV Pizzazz

[sveinung]

For "regatta telemetry" I wouldn't be too concerned about the 24/7 data use. Assuming this is just hours out of the week so should be very manageable.

Any good ideas for the cheapest test bed i could setup for a nmea system at home to develop on? Was thinking of buying a used GPS for instance, but haven't seen anything really cheap on eBay

[muttnik]

kplex might be worth a look.
NMEA-0183->serial-to-usb-converter->raspberry-pi-running-kplex->wifi->mobile phone in tethering mode->Internet endpoint->something running another instance of kplex
Upside: cheap hardware, free software, better control of reconnection and keepalives than most other options
Downside: Doesn't run on windows (but does run on mac). n2k would need to be converted to -0183 first. No security so you'd need to wrap it in something like an ssh tunnel or IPSec.

[muttnik]

Also to add...kplex will do filtering and rate limiting of nmea-0183 so if you only want a subset of your data, or you’ve got a fast heading compass but only want to transmit heading at 1hz, kplex can do that for you to minimise your Internet data usage