SeaTalk1 to NMEA 0183 converter, DIY

Updated 2024-08-30 ! 

!! Another SW solution is available for RPi 5 here ! using the same HW.

Thanks to Thomas, (the guy with the nice marine interface board), it's now possible to decode, one way, the SeaTalk1(ST1) sentences in a pretty simple way. You just use OpenPlotter(OP) and/or SignalK(SK) and an Optocoupler.

The thing that made it, is that Thomas has released a "how to" and Python source code, that will read the data from a GPIO pin on the Raspberry Pi, (RPi), and format it so the standard parser in SignalK can translate it to SignalK delta format. It is then available as NMEA 0183. It's even possible to send the data in to a NMEA 2000 network, with a proper hardware interface.

Waveshare CAN hat with Signal K & OpenPlotter

Updated 2024-07-08

To get information from the NMEA 2000(N2K) network, to the RPi, I have been using Actisense NGT-1, for a long time, and later also the Yacht Devices YDWG 02 but now it was time for a Raspberry Pi(RPi) CAN hat(CH) from Waveshare(WS). WS have 3 different models but I picked the 2 channel isolated one.

It's recommended to use an isolated one which also is demanded for those interfaces which can be approved by the N2K group.

Signal K charts, offline & online

Updated 2024-05-03 !

In Signal K(SK) there are 2 applications, in SK appstore, that can handle charts

• Freeboard SK(FSK)
• Tuktuk Chart Plotter(TT)

FSK, preinstalled, uses the OpenSeaMap charts(OSC) when you are online. If you want to use offline charts or other chart resources you have to install "@signalk/charts-plugin"(CP)

OpenPlotter V3, install guide

Updated 2024-03-01 !

OpenPlotter(OP), a Boat Navigation application, is really a nice and simple installation of

• OpenPlotter(OP)
• OpenCPN(OC)
• SignalK(SK) 

and other supporting applications for Your boat.

An overall information about the OP package is found here.

Install guide for the new stable OP, version 4, is found here.

Signal K quick install

Updated 2023-12-01 !

I have got some questions installing, just, Signal K(SK) so will do a summary, on a Raspberry Pi, with links.

Signal K is the hub to receive data, from different devices in different data formats, and send it on to different equipment, or databases, in different formats. Most common for standard marine equipment are the old NMEA 0183 and the newer NMEA 2000 protocol which is also handled. 

Besides the SK "hub" function developers have created plugins for different purposes. This is due to that SK is open-source ! Sharing is caring !

In this post you can check the devices I'm using connected to the SK server and also my setup.

NMEA WiFi gateway

Updated 2023-11-06 !

I have searched for a solution transmitting the NMEA data, from the navigation network, via WiFi, to for example iSailor or other Tablet/Phone applications.

Most of these applications just accepts NMEA0183(N1) but many boats are also using SeaTalk 1(ST1) and NMEA2000(N2K).

This post will cover, kept compact, my best findings covering both a DIY and a commercial approach to handle the different protocols.

SignalK, measuring temperature

Updated 2023-11-05 !

An introduction to the SignalK, Marine application, is given here.

A very easy way to measure temperature with Raspberry Pi, RPi, is to connect one wire (1W) DS18B20 (DS)temperature sensors direkt to the RPi GPIO.

Here You find a post where the temperatures are transfered via WiFi

Understand/Install Openplotter/OpenCPN/SignalK, II

Updated 2023-10-16 !

This post is the second post explaining the purpose with, and quick/simple install instructions for, OpenPlotter(OP) and some other applications that can be installed with OP. 

The first post is found here and in this post we will proceed with the install of OpenCPN(OC).

OpenCPN

Install

In OP:s "Application Meny => Other => Settings" app,  mark "OpenCPN Installer" and click on "Install", at the upper right. 

Understand/Install Openplotter/OpenCPN/SignalK, I

Updated 2023-10-15 !

This post, additional posts will follow, will explain the purpose with, and quick/simple install instructions for, OpenPlotter(OP) and some other applications that can be installed with OP. 

• OpenCPN(OC), is the plotter software where You navigate and handle charts 
• SignalK(SK), is the software where all the sensor inputs are handled. Could be NMEA data or SK formated inputs
• OpenPlotter(OP), is the administration shell where all is administrated

As You investigate the different software packages You will see that there are some overlap in the functions.

With OC 5.2 + there was several updates....

Seatalk 1 and NMEA2000 combined

Updated 2023-01-20 !

Our boat was delivered, 2006, with just Raymarine equipment using network Seatalk 1(ST1), and some NMEA0183(N1). Updates and additional equipment will use the newer NMEA2000(N2K). We will keep the two well functioning Raymarine 12”, E120, and the radar. In addition, for Navigation purposes, we use the iPad app iSailor.

The easy way to combine ST1 with N2K is to use the Raymarine Seatalk 1 to Seatalk NG(STNG) converter, Raymarine E22158. STNG and N2K is the same protocol, with some dialectal differences, but have different cabling.

Don't miss this post where I'm presenting additional solutions, including a NMEA WiFi gateway, and add ons.

NMEA 2000 temperature sensor, wet exhaust

In former posts I used the temperatur sensor DS18B20, in several applications, but now it was time for the boats exhaust temperature and checking out YDTC-13 from Yacht Devices(YDTC). (But please note that the YDTC can be used in any temperature application.)

When you are boating, using the engine, it's very important that the cooling water always is present otherwise major damages can follow. In "wet exhaust" systems it's easy to get the temperature which I posted here.

Read and write NMEA files, Openplotter, Signal K

This post is written for those who runs Signal K(SK), or applications that indirect are using SK, and want to write log files that could be read for later use.

Other applications could be Openplotter which includes SK or OpenCPN for example interfacing a NMEA 2000 network via SK.

There are sample files within the SK installation which can be used, for testing purposes, before you have created your own log files from your boat trips. Check here at "Input file/data".

Raymarine AXIOM and NMEA0183

Updated 2021-07-24 !

Many newer MFD:s don't have any NMEA 0183(N1) connector. The  Axiom don't even have any Seatalk NG connector anymore, just the Device Net micro connector for NMEA 2000. Loosing the  N1 info, too for example the old VHF (position data for DSC), could be a problem so how to solve it ?

Some solutions

• Pick N1 data from the AIS
• NMEA 2000, N2 to N1 konverter
• SeaTalk NG, NG to N1 konverter

Volvo Penta NMEA 2000 Gateway

Updated 2021-06-15

It's always nice to have ALL information at the same place, navigator/plotter, when You are out with the boat. 

What could be missing is the engine information/data. If You have a Volvo Penta from 2006 or later it could be pretty easy.

There are some "standard" NMEA 2000 gateways to choose from, for example; 

• Volvo Penta has it's own 22813366, 3889758
• Raymarine ECI-100
• Maretron J2K100
• .....

SignalK switch with NodeRed and WilhelmSK

Updated 2021-03-13 !

Here I'm trying to do the "ultimate" SignalK switch blog post including(no N2K)

• Shelly 1 as the hardware switch
• NodeRed as the function engine
• NodeRed dashboard as input/output interface
• WilhelmSK as input/output, check picture
• A http endpoint as state sensing

The post is ment to be a template where you can pick the parts which are right for your setup.

Raspberry Pi measuring Voltage

I'm always a little confused that as soon as someone wants to get an analog measure to a Raspberry Pi(RPi) they are often taking a detour via an Arduino/ESP or some other microcontroller. 

Why not just take an Arduino peripheral and use it together with a RPi ? 

In my case I needed to measure the voltage across a fresh water tank level sensor in our boat, but i could be any DC voltage. Hints for sending the data to a Signal K(SK) server is found below. 

In this post I will use an ADS 1115(AD), or ADS 1015, as AD converter.

Eniro charts using SignalK & Freeboard

Do you know about the SignalK workspace at Slack ? It's a really nice space where you could meet the developers and also get support.

If you don't are active there you can get an invite filling in your e-mail adress at

http://slack-invite.signalk.org

I'm following the dialog on Slack and for some weeks ago I stumbled over a post from @chris saying that you could get, with internet connection, the online charts from Eniro displayed in Freeboard. As you see in the picture it's just for the Nordic countries.

Another post installing offline charts.

SignalK, stream data changes

Are You searching for a solution where You want to create graphs and gauges from SignalK(SK) data ?

Use NodeRed(NR), installed as a SK plugin, with the standard dashboard and it's easy to create info as seen in the picture. And this is without a database as InfluxDB and tools like Grafana.

You use the WebSocket interface and subscribe to any change of data from the SK server. 

SignalK, measuring temperature II

An introduction to the SignalK(SK), Marine application, is given here.

A very easy way to measure temperatures with SK is to use one wire (1W) DS18B20 (DS)temperature sensors. 

In a former post the DS:s where connected direkt to the RPi GPIO:s, but in this post they are WiFi enabled via the Shelly 1(S1). Alarms are also sent when the temperature exceeds a set value.

If humidity is of interest You can use a  DHT22 sensor instead of a DS sensor.

OpenPlotter V2, NMEA or SignalK data TO file

A newer post on the same subject !!

If You want to capture Your data from a sailing trip there are several ways. Here I will check out these

• SignalK delta, via plugin signalk-data-logger 
• NMEA 0183(N1), via netcat
• NMEA 2000(N2), via actisense-serial

If you then want to use these files as input for OpenPlotter, OpenCPN or SignalK check out this post.