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.

Raymarine E120 & E80 backlight failure

Just the other day the backlight for our classic Raymarine E 120, Navigator(MFD), stopped working.

It's from 2006 so I'm not surprised that things happen. You may wonder why we keep it instead of buying a new one but the thing is that we have 2 installed together with a well functioning radar so buying new stuff will be a hefty price tag.

After some Googling I found out that the backlight is produced by a CCFL, a type of neon light, and can give up after some years.

The Googling also gave some tips how to change to a LED backlight. The picture above is showing a test with a short LED light strip to verify the solution, with dimming working, and checking the health of the MFD.

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.

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.

AIS receiver & dispatcher with OpenSeaMap

Updated 2023-11-09 !

The AIS posts on this blog have been very popular so this post will be a follow up which will enable You to show AIS targets, including AtoN:s, on OpenSeaMap, (OSM), together with buoys and beacons.

The application showing the map is SignalK, (SK) a OpenSource project for marine use. 

With the "ais-forwarder" plugin you could send/dispatch the NMEA AIS data to Marinetraffic or Vesselfinder. Another AIS-dispatcher.

The best AIS application ? is found here !

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

AIS for Raspberry with Map, Dispatcher

Updated 2023-11-04, OK with Bookworm 32 bit !

Not Bookworm 64 Bit !

This is a setup, on a Raspberry Pi(RPi), with a software package, AIS Dispatcher, from http://www.aishub.net which includes

• receiving and processing of all standard AIS messages
• streaming raw AIS feeds to multiple destinations
• advanced monitoring of device status, coverage and message statistics
• embedded electronic map with all received vessels

The best AIS application ? is found here !

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....

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

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 !

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.