Remote position and track plotting.

[MikadoII]

As a complete beginner with OpenCPN I am thinking of using it as a plotter at home to display a boat's position out on the water. The position info could be transferred via the internet or possibly as sms messages on the 4G network. I am an Engineer and Programmer but know nothing of OpenCPN. Has anyone done anything along these lines please?
cheers
Geoff

[Freedom45]

We keep track of buddy boats while underway by dropping a mark then edit it with their position.....

[conachair]

should be many ways to do it without too much programming if you have web access on the boat, node-red might be the quickest, on the boat use node-red to send the nmea sentence as mqtt to a web based mqtt broker then at home more red to get that nmea off the mqtt broker and forward it as as a local udp message which opencpn can see. Haven't tried that though...

[conachair]

Originally Posted by conachair

Haven't tried that though...

Just tried it, it works. a simulator running on a raspbery pi, node red sending to a cloud based mqtt broker, laptop with node red reading the mqtt and sending it to opencpn via udp. All nmea messages getting sent, not just lat & long

This is a free cloud based mqtt broker though anyone can see the data should they be interested

[MikadoII]

Conachair. Thanks for your suggestion and testing. I will add node-red and mqtt to OpenCPN for my study list and see what I can do. Ive also decided that I should know more about Linux so the current isolation is not all that bad a thing at the moment.

[MikadoII]

Originally Posted by conachair

should be many ways to do it without too much programming if you have web access on the boat, node-red might be the quickest, on the boat use node-red to send the nmea sentence as mqtt to a web based mqtt broker then at home more red to get that nmea off the mqtt broker and forward it as as a local udp message which opencpn can see. Haven't tried that though...

Could you please post your node-red diagram.

[conachair]

Originally Posted by MikadoII

Conachair. Thanks for your suggestion and testing. I will add node-red and mqtt to OpenCPN for my study list and see what I can do. Ive also decided that I should know more about Linux so the current isolation is not all that bad a thing at the moment.

Go for signalk, no question! Runs on linux or windows but a raspberry pi is perfect for use on a boat, openplotter has everything you might need.
It's all in there, node-red available as a signalk app and mqtt available as an app and as a node-red node. Little signalk can't do.
Sorry, deleted the flows already but looked ike this >

TCP node reads the data signalk puts out on TCP 10110, which can be basically anything coming in which can be an nmea sentence. This get sent to a cloud mqtt broker. Other end is pretty much the reverse though would be better going mqtt to UDP the set up a signalk connection to the udp port. Then you gain all the benefits of having the data as signalk.


http://signalk.org/
and a stripped down demo>
http://demo.signalk.org/admin/#/dashboard

[Dsanduril]

And if the boat has AIS you could either a)use a receiver if they are in range of your home to get their position; or b)subscribe to an internet AIS provider that provides such data. Both of those cost $, but may be viable depending on what options are available.

If you just want to see position and they have AIS you could always just use MarineTraffic or one of their competitors.

[MikadoII]

Conachair. At the moment I am trying to get on top of OpenCPN, Linux for a RasbPi, Node-red, MQTT etc. Also I am limited by the boat device.

It uploads the lat and long to ThingSpeak on a regular basis. Using node-red I can get this info down as follows:


"{"created_at":"2020-05-30T00:02:29Z","entry_id":3,"latitude":"-38.31","longitude":"145.2043","elevation":null}"


My problem is getting it into OpenCPN. My node-red diagram is below

OpenCPN is set up as below
What am I missing please? Your assistance would be greatly appreciated.
Geoff