Raspberry Pi as Onboard Computer

[JonathanX]

For this winter I am working at the moment to get ready for next season, as I have few android tablets so I could use them at the elm or carry any place in the boat with OpenCPN to control my ST4000+ or directly control the drive motor if the ST became defective and using all kind of sensors on Arduino board programmed with Visuino software witch you don't need programming language to use this and all of that communication in Wifi or Bluetooth.

[fxykty]

I have a Raspberry Pi 4 and the current release NOOBs OpenPlotter does not install on it. There is a beta thread on the OpenPlotter forum from which you can download a beta NOOBs of OpenPlotter and it sort of works on the Pi 4. Just a matter of time I suppose. So I guess if you already have it working on a Pi 3 wait until the release software is ready for Pi 4.

My difficulty, even after wading through multiple threads and sites about it, is how to connect the boat network to the Pi. I’m not much of a techie and I’m just confused.

I’ve got a mixture of Raymarine chart plotter, pilot, GPS and instrument displays and ICOM radios, GPS and AIS. All connected via Seatalk ng cables and some NMEA 0183 direct wiring from the ICOM components into the Seatalk ng network.

Do I need just one Seatalk to USB converter such as the Actisense NGT-1 https://www.actisense.com/products/ngt-1/ to have two way data from my Seatalk ng network to and from the Pi? Or do I need NMEA 0183 as well? My chart plotter has all the info I want for the Pi, so shouldn’t the Seatalk ng data be enough?

Once i have the connection with the Pi then OpenCPN and PyPilot should be able to read and write back to the plotter and pilot, right? And I assume using SignalK I can send data from the Pi to my iSailor apps on phone and tablet?

[thomm225]

On second thought, there's no way I would be happy with a 7" monitor.

I was just thinking about some of the small chart plotters, etc they have on display at West Marine probably to be mounted at the helm/wheel.

I'll probably stay with at least a 17" monitor like the laptop I use on the boat at times

[conachair]

Originally Posted by fxykty

I have a Raspberry Pi 4 and the current release NOOBs OpenPlotter does not install on it. There is a beta thread on the OpenPlotter forum from which you can download a beta NOOBs of OpenPlotter and it sort of works on the Pi 4. Just a matter of time I suppose. So I guess if you already have it working on a Pi 3 wait until the release software is ready for Pi 4.

The ********.img.zip on here works on a Pi4, at least the december download did. Most if it there now, just a few apps to finish by the looks of it.
OpenPlotter 2 roadmap
Re Network, mine creates an Openplotter wifi network using the inbuilt wifi adaptor and also connects to a network created by a smartphone to get webaccess. set up in the network app.


Don't know much about seatalk ng but that cable has been mentioned as supported.

[Reefmagnet]

Originally Posted by steffan

Fun thread...
...
My difficulty, even after wading through multiple threads and sites about it, is how to connect the boat network to the Pi. I’m not much of a techie and I’m just confused.

I’ve got a mixture of Raymarine chart plotter, pilot, GPS and instrument displays and ICOM radios, GPS and AIS. All connected via Seatalk ng cables and some NMEA 0183 direct wiring from the ICOM components into the Seatalk ng network.

Do I need just one Seatalk to USB converter such as the Actisense NGT-1 https://www.actisense.com/products/ngt-1/ to have two way data from my Seatalk ng network to and from the Pi? Or do I need NMEA 0183 as well? My chart plotter has all the info I want for the Pi, so shouldn’t the Seatalk ng data be enough?

Once i have the connection with the Pi then OpenCPN and PyPilot should be able to read and write back to the plotter and pilot, right? And I assume using SignalK I can send data from the Pi to my iSailor apps on phone and tablet?

IMO, you're better to connect all your N2K stuff up together and then run it to the PI via a single N2k to 0183 gateway. You need to join any 0183 stuff to the pi separately (using USB to RS422 adapters seems to work best). OpenPlotter has KPlex installed which lets you combine input sources into outputs. Usually you'd combine your wired N2K and 0183 inputs and output them on the wifi so tablets and computers can access the data. 0183 AIS can be a bit tricky, because it runs at 32800 baud and some gateway devices wont handle this - check the specs of the gateway device. Bi-directional transmission on the gateway is not a problem (as long as it is bi-directional in the specs) and I suspect most, if not all, will drop any messages they originally TX'd on RX to stop cyclic loops.

[Reefmagnet]

Originally Posted by steffan

Fun thread...

I'll preface my reply with the fact that I have just bought my boat and haven't installed anything on her yet. Agree that this is probably only worth it if you enjoy this sort of messing around.

On my desk at home I have OpenPlotter installed on a Pi 3B+, and made it a Plex server+client for movies at anchor. This model Pi struggles to playback video so I will upgrade to a Pi 4 before installing on the boat. Movies will be stored on a USB 3.0 external SSD.

I have the GX2200 VHF mentioned earlier in the thread as this looked like the cheapest way to inject GPS and AIS data. OpenPlotter makes it pretty easy to watch the NMEA0183 sentences flow through and I've seen the GPS data do that. As far as I can tell the GX2200 doesn't broadcast it's AIS demo data so I have not seen those yet.

Right now the radio is wired into a RS422 USB stick on the Pi. This required reversal of the grey and brown wires to work, for some reason. I plan to add a Yacht Devices multiplexer to bring other data in at some point.

A decent 5.2V, 25W power supply will get soldered to the PI motherboard before installation, and I will be using a case with an integrated fan and heatsinks. I may solder the RS422 daughterboard on there too, and secure the whole works to some plywood.

A likely reason for the need to reverse the wires is that some RS 422 adaptors can have their definitions of "RX" and "TX" interchanged. I purchased a number of adapters from two different sources and even though essentially the same chip sets, the RX and TX was swapped on the terminal labeling between the devices. That just adds to the fun!



Some devices also connect a bit differently than logic would dictate because the NMEA 0183 standard kind of moves between RS232 and RS422 which use unbalanced (3 wire) and balanced (4 wire) transmission respectively, depending on the device it's implemented on.

[thomm225]

What do you folks use to connect to and extend the short NMEA wires on the devices you want to hook up to your Raspberry Pi

[Singularity]

Originally Posted by thomm225

What do you folks use to connect to and extend the short NMEA wires on the devices you want to hook up to your Raspberry Pi

Adapters are shown in this video. I've linked it to start right before the hardware descriptions, but the entire video is 8-9 minutes (starts with an intro to Pi as an onboard computer).
https://youtu.be/U3ucE3Rx7Tw?t=149

The above said, I'm wondering what the max USB wire lead can be between the NMEA-USB adapter and the Pi before voltage/signal is lost...?

[Bill O]

Max length for a usb2.0 cable is 5 meters while a 3.0 is only 3 meters.


Bill O.

[fxykty]

Originally Posted by Reefmagnet

IMO, you're better to connect all your N2K stuff up together and then run it to the PI via a single N2k to 0183 gateway. You need to join any 0183 stuff to the pi separately (using USB to RS422 adapters seems to work best). OpenPlotter has KPlex installed which lets you combine input sources into outputs. Usually you'd combine your wired N2K and 0183 inputs and output them on the wifi so tablets and computers can access the data. 0183 AIS can be a bit tricky, because it runs at 32800 baud and some gateway devices wont handle this - check the specs of the gateway device. Bi-directional transmission on the gateway is not a problem (as long as it is bi-directional in the specs) and I suspect most, if not all, will drop any messages they originally TX'd on RX to stop cyclic loops.

I don’t want to buy a separate gateway - that’s what the Pi is for. My Seatalk ng network gets all the NMEA 0183 data from their sources and sends it to/from the plotter, pilot, radar and instruments. Doesn’t the Seatalk ng network now have all that data as its used to send to and receive from the i70 instrument display and p70 controller so I just have to connect it to the Pi?

Still confused. What exactly is needed to keep things as simple as possible? This is to get the boat instrument/plotter/pilot/radar/AIS/GPS data into and from OpenCPN and PyPilot running on the Pi. Secondary purpose is to use the Pi to send data via WiFi to phones and tablets and other consumers of the data.

[thomm225]

Originally Posted by Singularity

Adapters are shown in this video. I've linked it to start right before the hardware descriptions, but the entire video is 8-9 minutes (starts with an intro to Pi as an onboard computer).
https://youtu.be/U3ucE3Rx7Tw?t=149

The above said, I'm wondering what the max USB wire lead can be between the NMEA-USB adapter and the Pi before voltage/signal is lost...?

Great thanks. Lots of good info on that video.

I guess I may have to go straight to a terminal board or USB adapter to lengthen the wiring.

I've only been on this project for a day or so and thought I had to bring in the 4 NMEA wires directly to an RS 485 top hat, but it looks like I may be able to use usb instead?

[Reefmagnet]

Originally Posted by fxykty

I don’t want to buy a separate gateway - that’s what the Pi is for. My Seatalk ng network gets all the NMEA 0183 data from their sources and sends it to/from the plotter, pilot, radar and instruments. Doesn’t the Seatalk ng network now have all that data as its used to send to and receive from the i70 instrument display and p70 controller so I just have to connect it to the Pi?

Still confused. What exactly is needed to keep things as simple as possible? This is to get the boat instrument/plotter/pilot/radar/AIS/GPS data into and from OpenCPN and PyPilot running on the Pi. Secondary purpose is to use the Pi to send data via WiFi to phones and tablets and other consumers of the data.

N2K is proprietary (which explains the price of gateways) though (I think!) you can do what you're suggesting with a CANBUS adapter on a Pi. Me, I just use a gateway as it's a lot simpler.

[Reefmagnet]

Originally Posted by thomm225

What do you folks use to connect to and extend the short NMEA wires on the devices you want to hook up to your Raspberry Pi

I used offcuts of NMEA 2K cables and the old shielded wire from the original instrument wiring that was still good. Network patch cable can be used for RS 422 connections using a twisted pair for each RX and TX. For short distances, plain wire is fine. You can also use USB extension leads up to, say, 3m as Bill suggested.

[thomm225]

Originally Posted by Reefmagnet

I used offcuts of NMEA 2K cables and the old shielded wire from the original instrument wiring that was still good. Network patch cable can be used for RS 422 connections using a twisted pair for each RX and TX. For short distances, plain wire is fine. You can also use USB extension leads up to, say, 3m as Bill suggested.

Thanks. 3m is plenty of length

[Reefmagnet]

Originally Posted by thomm225

Thanks. 3m is plenty of length

Makes the Pi look neater too, without the dongles hanging off the back of it. My Pi is velcro'd to the top of the VHF so without the extension leads, it would look fugly!