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.

OpenPlotter v4 stable, install guide

Updated 2024-06-30 !

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 

and you can watch the OP v4 progress here.

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.

GRIB files and extracting data, Linux, Raspberry

Updated 2024-02-08

GRIB is a data format, used for meteorology, to store historical and forecast weather data. 

The use case for me was analyzing forecast data, from GRIB files, so an early warning could be rised before a high water level or coming storm appears. This could then be used at our weather site.

There are several applications, also ones that visualizes the data, but this post will handle how to extract data from files using command line.

Forecast without GRIB files ? Check this API for Europe.

AIS reciever for Raspberry Pi, 2 channel

Updated 2024-01-20 !! OK with Bookworm !!

This post covers the setup for a AIS, dual channel, receiver for Raspberry Pi(RPi) with systemd autostart.

I'm using the RTL-SDR dongle V3 with almost zero temperature drift or the even better NooElec NESDR Nano 3

AIS posts with charts/maps

• OpenSeaMap and dispatcher 
• OpenStreetMap and dispatcher

Improve receiving range? Calibrate ! Instructions in this post

The best AIS application ? is found here !

SDR calibrate with kalibrate-rtl

Updated 2023-12-05 !! OK, with Bookworm (32/64 bit) !!

To optimize the reception with SDR:s, Software Defined Radios, it is important to receive on the proper frequency. Due to variations in production there could be deviations.

The calibration could be done against standard GSM transmitters which are providing a stable reference frequency.

Another way is found in the AIS-catcher application and use the information supplied in the graphs "Frequency Shift". 

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.

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....

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.

Exhaust temperature measure, boat

Updated 2022-06-10 !

In other posts I blogged about a way to measure temperature with a Raspberry Pi(RPi), direct connected or via WiFi, together with the marine applikation SignalK(SK). In this post I will follow up with a short brief about the practical solution, measuring exhaust temperature in a boat and sending an alarm if the temperature exceeds a set value .

In "wet exhaust" systems it is very important that the cooling water, injected in the exhaust system, always is present otherwise major damages can follow.

If you wan't to avoid a RPi check this post with approved NMEA 2000 temperature sensors from Yacht Devices 

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".

Victron VE.Direct with Raspberry Pi/Signal K

Updated 2022-01-11 !

During my update of the cables going from the batteries, to the distribution panel and engines, I stumbled over the Victron SmartShunt(VSS). We had a 15 year old Mastervolt battery monitor but it didn't feel "true" and it wasn't at the right place in the boat. So instead of moving the old shunt we bought a VSS. 

AIS dispatcher, stand alone

Updated 2021-07-14 !

The dispatcher "aisdispatcher"(AISD), Linux v1.2, from AISHub.net receives NMEA 0183 VDM/VDO messages, (NAIS) via an UDP/TCP connection, or serial interface, and forwards it to one or several destinations as UDP streams. It works at command line with no GUI.

Please note ! This software is "labeled" deprecated and the AISHub guys recommend you to use this package, with built in GUI, instead. The old version, described in this post, still works, for RPi OS before Bookworm, and is very lightweight.

The best AIS application ? is found here !

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.