OpenPlotter project

[Alekoy]

The Elm is made for OBD in cars and converts the standard protocols and does a lot of the heavy lifting when it comes to decoding the data.

And N2k is NOT one of the protocols the ELM supports, even if it is canbus...

[Nick_Currawong]

Hi Alekoy,

Is it the protocols that are the issue? Or is it a application software issue?
Just trying to get a better understanding of what to look for that might work because a bi-directional wifi connection into my SeatalkNG network would make life so much easier.

From Wikipedia for both ELM327 and NMEA 2000 , they both support SAE J1939, N2K says it is based on and works in accordance with that protocol. N2K implements a protocol called "NMEA 2000 Fast packet", but it still seems to imply that it falls under the SAE J1939 250kbps protocol.

Thanks

[Alekoy]

Imagine that n2k is in "english"
And the ELM chip is made to translate polish, russian, spanish, french etc to AT-commands that the computer can use to ask what has been said to the ELM-chip.

Sure they are all languages (protocols) based on words (CAN-bus), but as long as the elm does not know the language (protocol), you won't get anything usable out of the other end of the translator.

The €35 N2k to USB converter from the Sailoog store does not translate anything, it just converts CAN to serial data, and then there is software that translates it to something understandable.

The n2k dongle and openplotter should be able to decode seatalkNG to something useful, if not now, sometime in the near future.

[Alekoy]

After some research, it turns out that the ELM329 does support n2k IF you do some setup and stuff, setting it in direct mode.

You will still need to decode the data and so on, and it does only receive..
So the openplotter and n2k adapter will be a quicker, more simple way to reach your goal.

read more:
Elm Electronics - OBD Users

[Arne Henriksen]

Originally Posted by Harry Brown

Could someone recommend a Pi3 / openplotter compatible wireless keyboard and mouse please? Should I go Bluetooth or WiFi?

After some searching I found this BT keyboard, which is kind of smallish and has internal lighting for my night/wintertime uses... :-)

Apart from the ~3-second wakeup delay when it has gone to sleep, it seems to be working very well on my Pi3.

[seandepagnier]

Originally Posted by Alekoy

You can make a Navtex-receiver even cheaper with just a SDR, and let the software do the decoding.

What software can do it?

Originally Posted by petter5

95% of the time ... 2 keys for multimedia functions and you will have to press shift to get access to the F1 to F12 functions, not so convenient when it's a little choppy waves and you try to operate your navigation pc.

The idea is in the near future to make all the keys rebind able in opencpn so each user can optimize what each key does.

Originally Posted by Rich UK

I've been looking can't find one that covers that frequency of 518Khz

I have a ham it up upconverter I think it costs $50

Originally Posted by Vamonos

It appears that your best bet is to use an up converter.

https://www.itead.cc/spyverter.html?...e7dff9f98764da

Yes, so I can in theory recieve 518khz, but there are still noise issues at these low frequencies for me, perhaps I need a different antenna, and analog filter etc...

What is the ideal antena for navtex? Where do I get software that can decode raw audio into navtex?

[Nick_Currawong]

Hi Alekoy or anyone else,

After more reading and hopefully a better understanding of what I want!

We don't need the ELM chip as you say it's doing all the translations, which we don't need.

So I/we would like a very basic setup like a CAN transceiver (MCP2551 chip) to do the reading/writing to the bus without any translation and a wifi module. That way you just get raw data to the RPi and let the software handle it all.

Is that a possibly? Or have I still not got the correct understanding of process?

I have ordered a CAN-USB adapter to get it working.

Thanks

[Alekoy]

Originally Posted by boat_alexandra

What software can do it?

There are some alternatives out there already, google "navtex decoder software" or similar, maybe it is possible to find an open source project and integrate it into openplotter in the far future.

Originally Posted by Nick_Currawong

Is that a possibly? Or have I still not got the correct understanding of process?

You are getting there

-Connect the CAN-dongle to the bus and plug it into the RPi,
-Set it up
-Connect a wifi-dongle to your RPi (not needed if you have a Rpi3)
-??
-Profit!

Keep in mind that it is very early in the N2k-development for openplotter and things are not optimized.

Read more in the manual

[Sailoog]

Our low-cost CAN-USB stick is working perfectly, you won't need anything else, plug and play.

The converter sends raw N2K data to the Raspberry USB port, canboat library is in charge of translating to something more human-readable and finally Signal K translates to Signal K format. By this moment OpenCPN is not able to read Signal K but they are working on it. You will be able to use all the future Signal K apps.

The converter is bi-directional but for security reasons all the PGNs (old NMEA 0183 sentences) are blocked. You have to unblock the desired PGNs by software to transmit. This software will be integrated in OpenPlotter v0.9.0. There will be also an "inspector" to see what is going in and going out of your converter. That means that you will be able to send the connected sensors to your N2K network.

This is the diagram, we still have to decide if sensors will send data directly to the converter or it will be Signal K server.

[NahanniV]

Originally Posted by Sailoog

Our low-cost CAN-USB stick is working perfectly, you won't need anything else, plug and play.

The converter sends raw N2K data to the Raspberry USB port, canboat library is in charge of translating to something more human-readable and finally Signal K translates to Signal K format. By this moment OpenCPN is not able to read Signal K but they are working on it. You will be able to use all the future Signal K apps.

The converter is bi-directional but for security reasons all the PGNs (old NMEA 0183 sentences) are blocked. You have to unblock the desired PGNs by software to transmit. This software will be integrated in OpenPlotter v0.9.0. There will be also an "inspector" to see what is going in and going out of your converter. That means that you will be able to send the connected sensors to your N2K network.

This is the diagram, we still have to decide if sensors will send data directly to the converter or it will be Signal K server.

Will it be possible to Mimic proprietary PGNs like the ones sent by autopilot controllers ?

[Harry Brown]

Originally Posted by Arne Henriksen

After some searching I found this BT keyboard, which is kind of smallish and has internal lighting for my night/wintertime uses... :-)

Apart from the ~3-second wakeup delay when it has gone to sleep, it seems to be working very well on my Pi3.

Thanks very much for that, looks perfect!
Still looking for a Bluetooth mouse if anyone could recommend a good one please?


.

[richarddaneel]

Hi guys, any help appreciated. I have got a GPS running on Bluetooth and the OP on rpi3 which picks it up no problem. However, when I try and connect it keeps telling me - connection failed - no usable services on this device. However, Opencpn runs beautifully with the setup on my PC. thx Richard

[affinite]

I'm having a problem with my Raymarine Seatalk to NMEA converter giving incorrect Apparent Wind angle data (VWR).
The output from the wind sender is OK as it displays OK on my ST60 wind display instrument
I seem to remember someone dealing with this but cant find the thread. Any ideas ?
BTW the data stream for other sentences seems OK and I'm getting water depth and wind speed without corruption so the connection is OK
Any ideas?

[Opie91]

Originally Posted by affinite

I'm having a problem with my Raymarine Seatalk to NMEA converter giving incorrect Apparent Wind angle data (VWR).
The output from the wind sender is OK as it displays OK on my ST60 wind display instrument
I seem to remember someone dealing with this but cant find the thread. Any ideas ?
BTW the data stream for other sentences seems OK and I'm getting water depth and wind speed without corruption so the connection is OK
Any ideas?

I have seen that out of Raymarine stuff before. Did you have to calibrate the needle to to the wind vane when you installed the Raymarine system?

For some reason Raymarine stuff does not output the corrected wind angle on some of there indicators.

[rgleason]

Re seatalk & raymarine inst. Calibration very important. Also use of nmeaconverter_pi might help get you the sentence.