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OpenPlotter and autopilots
#1
I am having some troubles wrapping my mind around all things auto pilot.

What I would like to understand is how to duplicate the +/- 10 degree and +/- 1 degree functionality of the control buttons that are on my Raymarine ST4000+.
It would seem to me that all I need to do is to send some kind of a NMEA 0183 sentence to the E80 display that would then translate the sentence onto it's attached Seatalk bus which then reaches the autopilot and magic happens.
At this point I need a hint as to either what the magic NMEA sentence(s) is/are or a pointer to a URL where I might find documentation that could lead me to that magic sentence.
Somewhat related, currently my AIS feeds data via NMEA 0183 to the E80 chart plotter. I will need to feed that data into openPlotter and from there it needs to go back out to the chartplotter via it's NMEA 0183 input. I can then add the magic autopilot sentences to the stream and presto .... I hope. Has anyone written up how to combine the two streams (AIS and autopilot) ? It would be great if I could find something that shows me how to go about doing this.
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#2
I've heard of people simulating Autohelm control on the Seatalk bus, which can be found in a couple of places on the Internet. There are somewhat detailed instructions on how to turn a low-cost RF remote into an autopilot control (http://berreizeta.blogspot.mx/2016/10/se...oller.html). NMEA APA and APB sentences also have some control functions available (here is a good reference http://www.catb.org/gpsd/NMEA.html#_apa_...sentence_a).

As for multiplexing NMEA streams, Openplotter (using KPLEX) does that very well. Just bring both streams into a separate input, then output them to both your OpenCPN instance and your E80.

Not sure that answers your question - perhaps I misunderstood what you are trying to do.
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#3
Thanks abarrow. The second link to the NMEA sentences is quite interesting. I wasn't able to make any sense out of the other link.
Yes, I am feeding various data into openPlotter and from there I am feeding the data to the chart plotter. I do not need to talk directly to the Seatalk bus because the chart plotter is hopefully translating it's NMEA 0183 input onto the Seatalk bus. The idea is to add a NMEA sentence to the data to cause the autopilot to go up or down in the heading.
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#4
I have the non-ST version and connected a relay board to the wired remote output as discussed here:
http://www.cruisersforum.com/forums/f13/...68163.html

There is some talk there about how it might be approached on an autohelm ST4000. But it does seem to me that the guy in abarrow's first link is way ahead of this.
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#5
Hummm, you got me to thinking. I built a WIFI autohelm remote using an ESP-12 several months ago. The intention was that it would interface with Seatalk and push the right commands into the bus to convince the Autohelm that it was getting commands from a Seatalk Autohelm controller. My design works with the boat's WIFI network (thanks to OpenPlotter) and allows control from a smartphone browser. I could never get it to talk properly to the Seatalk network, so shelved the project for a while while working on other things.

Looking at this, providing a relay output to the existing design would be trivial, and would avoid the issues of emulating SeaTalk. All that would be needed would be to pick up a few GPIOs from the ESP-12.

What would also be interesting is that once on the WiFi network, it would also be fairly trivial to have NodeRED also send commands via REST, as that's how the existing smartphone interface works. So, you would get a certain level of automatic control from OpenPlotter, without getting involved in NMEA-SeaTalk interchanges.
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#6
(2017-06-16, 06:18 PM)abarrow Wrote: Hummm, you got me to thinking. I built a WIFI autohelm remote using an ESP-12 several months ago. The intention was that it would interface with Seatalk and push the right commands into the bus to convince the Autohelm that it was getting commands from a Seatalk Autohelm controller. My design works with the boat's WIFI network (thanks to OpenPlotter) and allows control from a smartphone browser. I could never get it to talk properly to the Seatalk network, so shelved the project for a while while working on other things.

Looking at this, providing a relay output to the existing design would be trivial, and would avoid the issues of emulating SeaTalk. All that would be needed would be to pick up a few GPIOs from the ESP-12.

What would also be interesting is that once on the WiFi network, it would also be fairly trivial to have NodeRED also send commands via REST, as that's how the existing smartphone interface works. So, you would get a certain level of automatic control from OpenPlotter, without getting involved in NMEA-SeaTalk interchanges.

Perhaps it would be easier to push autopilot commands by NMEA2000 ?
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#7
Perhaps, but I have an old Auto Helm that only speaks Seatalk..

Sent from my LG-K580 using Tapatalk
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#8
(2017-07-12, 02:11 PM)abarrow Wrote: Perhaps, but I have an old Auto Helm that only speaks Seatalk..

Sent from my LG-K580 using Tapatalk

Me too, but I have a SeatalkNG(NMEA2000) to Seatalk converter that allows it to be controlled from the newer NMEA2000 heads.
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#9
Which converter are you using?
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#10
(2017-07-13, 01:44 PM)abarrow Wrote: Which converter are you using?

This one:

https://www.thegpsstore.com/Raymarine-Se...P3443.aspx
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