Connect and control ST2000 autopilot

[MigGat]

Hello everyone,

I have an old Autohelm ST2000 (pre-raymarine version, no NMEA, only SeaTalk), that i would like to control from OpenPlotter, to use it with signalk-autopilot. That would be the last step in the current "OpenPloterization" of my boat 

I know this topic is partially covered in this thread but i understand most of the information is obsolete after the release of the GPIO app.

That being said, i have serious issues figuring out:

1) The needed hardware to connect my Raspberry Pi4 + Moitessier HAT to ST2000. Especially if I can achieve it without "crafting" any PCB, cause I don't have the skills (I will learn them if no alternative, of course).

2) How to setup gpio app.

Any help will be greatly appreciated, thanks!

[serh11]

Isn't it that gpio app is only capable of receiving Seatalk 1 stream and transmission is not possible at the moment?
If that is true, then no control with this app is possible for now.
Otherwise there is a signalk module signalk-autopilot which is capable to control Seatalk1 autopilot by sending custom $STALK1 nmea messages. It is supposed to be used with a device which would convert $STALK1 messages to actual Seatalk1 signals, so in order to work with gpio app it would need some development.

[MigGat]

Then i'm certainly confused 

According to this post @Cari20 managed to make it work, i'm just not sure to understand how, or what's the required hardware.

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Alternatively, would it be possible to use the @seandepagnier's motor controller to control this autopilot? Because that would be an option too.

[serh11]

As @Cari20 mentioned:

...
First, a little about the hardware:

I used the bidirectional interface published by Thomas Knauf:

http://www.thomasknauf.de/rap/seatalk3
...

And then RXD signal of this interface is connected to the GPIO used by this new gpio app, while TXD signal is connectd to a TX pin of RPI's UART port, so the data can be sent to the interface.
There is indeed additional hardware involved.

[MigGat]

Thank you for your time @serh11!

This is currently above my skills, but since components are so cheap, i might as well, use it as a learning project when i have a bit more time.

[Sailoog]

openplotter-gpio app can only get data from seatalk 1 devices.

If I am not wrong those ST2000 devices have seatalk 1 in/out but they also have NMEA 0183. If this is true you have just to connect a cheap USB-RS422 converter and configure OpenCPN.

EDIT

Ops sorry I did not read your device does not have NMEA

[MigGat]

Sadly this is the oldest model and it only has SeaTalk1 (triple checked it), and i found no one who sell the PCB already done, so i guess the only choice is make it myself.

Already watching for tutorials on how to get started :S

[Sailoog]

Do you have any device in your seatalk 1 network with NMEA input? maybe a plotter?

Per cert, veig que has completat la traducció de OpenPlotter a català. Moltíssimes gràcies! si vols et puc fer arribar un prototip de el nou MacArthur HAT en la pròxima tirada que suposo que ja estaran a prop de la versió final perquè vagis jugant si et ve de gust.

[MigGat]

Do you have any device in your seatalk 1 network with NMEA input? maybe a plotter?

That one would have been cool, to have another instrument doing the translation job (didn't thought about it), but no, the only other device on board is a Garmin GPSMap520, which only has 2 x NMEA0183 ports.

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Si, lo de la traducció al català ha tingut la seva conya: entre optimot, softcatlà, i un parell de diccionaris nàutics, i encara hi ha coses que em sonen marcianes. Encara li vull fer una altra revisada però, perquè en les primeres traduccions hi havia parts d'aplicacions que no havia tocat 
I si i tant, estaria genial poder trastejar el nou HAT!

[Sailoog]

Then you do not have an easy solution. Seatalk 1 is not friendly electrically (the 9 bits parity issue) and you need special hardware. If there is a reasonable demand it could be included in Signal k, 1 GPIO for input and 1 GPIO for output.

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No pateixis ja la revisarem si cal. Ja et dire quelcom quan arribi el nou lot de HATs. Merçi!