OpenMarine

hello folks

I'm new here. Just boat my sailboat a month ago, and going the DIY route with the navigation system. I have an old Raymarine installation, consisting of a St30 bidata speedo / depth , an anemometer, and a autohelm st4000 pilot.

My goal is to feed all of them in Openplotter. Question is, is it possible to link the seatalk bus to a multiplexer and get all the data correctly in openplotter ? I know this is some really old stuff, but all the instruments are working so why replace them.

Help would be much appreciated

Thanks

https://www.youtube.com/watch?v=XFOGrBmD...ailingBoat
https://openplotter.readthedocs.io/en/la...l#seatalk1

Yes, using OpenPlotter GPIO you can take a feed from your SeaTalk network and bring the data into OpenPlotter. You can't go both ways, just Seatalk -> Openplotter (SignalK). You don't need any sort of multiplexer, just connect to the SeaTalk bus.

It requires a fairly simple signal level converter to bring the 12V Seatalk to the TTL levels that GPIO expects. These work well, but you do have to change a resistor: https://smile.amazon.com/gp/product/B01L1OI1HC/?th=1

You can also use a cheap multiplexer – about 55 Euro – like the Nmea3Wifi or Nmea4Wifi. The first one has SeaTalk 1 bidirectional capabilities and the second one only SeaTalk 1 to NMEA0183 capability, both from, www.vela-navega.com.

Thanks for your answers !

If i got it correctly : if i plug the seatalk wires directly to the Pi's GPIO , i'll get the data but won't be able to send.

But a multiplexer could do bidirectionnal data tranfer.

By bidirectionnal, does it mean i can control the pilot in Openplotter ?

"if i plug the seatalk wires directly to the Pi's GPIO".
dont do that its 12v it will fry your pi.

Yes sorry I was meaning no multiplexer in between. An optocoupler should do the trick to get the signal from the seatalk instruments to PI's GPIO

(2023-01-31, 12:04 PM)Elmumu Wrote: [ -> ]If i got it correctly : 
But a multiplexer could do bidirectionnal data tranfer.

Bidirectional is possible in SOME multiplexers.  Many are only one-way.  Here's a few that are bi-directional:
https://yachtdevicesus.com/products/nmea...828f&_ss=r
https://shipmodul.com/miniplex-3.html
https://digitalyachtamerica.com/product/st-nmea-usb/

What I have done is use an optocoupler to the Pi to receive Seatalk from the gauges and then connected via a USB to RS422 to send data via NMEA0183 to my ST4000 autopilot, that has a NMEA0183 input on the back.