Signal K help please

[david_bagshaw]

Just starting with signalk

Have an ikcommunicate box and have wired it up and it all works on network, putting out nmea to open cpn from ais class b from digital yacht, and the signal k gauges app works.


What I would like to do,

have a signal k display that shows the led lights of the AIT 2000, which has the latest firmware.

Any clues as to how I get the presumably proprietary sentences, on to the nmea data stream , & then what to do with them there on.

I suspect, $PSMT,255,get_leds,74,10*1B is the sentence, as there are 4 leds, and 4 Similar sentences ending in B,C,D,E as seen using the set up prog pro ais2 to display raw data.



I did some BASIC programming years ago, along with web pages including CSS, but nothing further.

 

[GHA]

Looks like those sentences are likely coming from a SRT board >
http://yachtelectronics.blogspot.com/2011/02/srt-proprietary-ais-commands.html

But ........ "Unfortunately neither SRT nor any of the vendors publish the protocol."

I suspect, $PSMT,255,get_leds,74,10*1B is the sentence, as there are 4 leds, and 4 Similar sentences ending in B,C,D,E as seen

The "*1B" is a checksum, it's just a check that the data in the actual message isn't corrupted.
But in your example the checksum is wrong or they use a different method to NMEA....

http://www.hhhh.org/wiml/proj/nmeaxor.html



So is your signalk V1.16.0 ?

That version has node-red built in so if you can find some details of the messages then you can pretty much do what you want.

 

[david_bagshaw]

Thanks for the reply, and the most useful links ! Some real gems there.

The i kcommunicate also has its latest firmware, but stupidly haven't checked to see if those sentences arrive on the device, only that they are listed in the ait 2000 out bound. data stream.

will play some more when on board, now I have the info from the links

Ta

 

[GHA]

If you can find the non standard nmea messages then filtering them through node red into signalk deltas shouldn't be that hard. Node red should be in the latest signalk.

 

[laika]

The SMT sentences were from later SRT boards than the ones Kees describes in his blog which GHA references. It's definitely worth pinging Digital Yacht explaining what you plan on doing and the information you need. They've done (imho) a great job of bringing the ikommunicate to maket, they've actively encouraging development ( see https://github.com/digitalyacht/ikommunicate/wiki/iKommunicate-Developer's-Guide-(SDK)) and if their relationship with SRT allows them to give you the info you need I'm sure they'll help. Failing that, try posting on the SignalK google group and your last resort is protocol snooping and reverse engineering the old fashioned way. If proais2 allows you to see raw traffic great. If not let us know: It's doable with a raspberry pi and kplex.

Bear in mind that once you've worked out how this stuff works you'll then need a way of representing it in Signal K as it's possibly not the case that there is a translation from NMEA-0183. DY and the Signal K forum are your go-to references there.

Also I'm wondering if, like the older SRT boards like my AIS, this is a query-response thing. "get_leds" looks very query-esque. What you'll then need is something to do the querying to elicit the response.

Looks like DY intend their ikommunicate apps to be html5-y...

Sounds like an interesting project. Let us know how it goes

 

[david_bagshaw]

Thanks for your help, have e mailed Paul Sumpner, of Digital Yacht, who was extremely helpful in the past & and will keep you posted as to how i get on.

 

[SiteSurfer]

I second that, Paul was most helpful when I realised that I needed an iKonvert not the iKomm device, so much so that I just bought another (ISO) version to go belt and braces on the network.