Originally Posted by sparticle
Custom NMEA sentence processing.
Is it possible to have OpenCPN process custom NMEA sentences (one we define for our own purposes). We are looking at using low cost, low power
sensors talking to our sensor controller and creating custom NMEA sentences with ship data that we may want to display in OpenCPN as dashboard items and publish on the network.
There certainly are possibilities, which one is usable depends on your particular application.
standard allows extension by vendor custom sentences, although after the decades of it's existence, there are exactly 7 of them we know about (https://github.com/mariokonrad/marna...tence.hpp#L137
For your case you have basically 4 options (ordered by the amount of work involved):
- Abuse an existing sentence you otherwise don't use and OpenCPN can handle (fastest and easiest if you are building a one-of system and all you want is it "somehow" works on OpenCPN /or anything else not offering any customization at all/, but of course very, very, dirty)
- Create your unofficial vendor extension to NMEA0183 and use the NMEAConverter plugin to abuse an existing sentence inside OpenCPN (won't need you to change the sentence once millions will love your gadget and you will certify it with NMEA, otherwise pretty much the same as above)
- Create your unofficial vendor extension to NMEA0183 and implement it in OpenCPN's dashboard.
- Create your unofficial vendor extension to NMEA0183 and implement a universal, configurable, instrument for OpenCPN's dashboard (This sure is by far the most work, but probably the only one where you get any attention from other developers here)
If you want more info, be a bit more specific about what exactly you want to achieve.
And SignalK is the future for this kind of stuff, of course.