DMI forecast API for atmosphere, ocean and sea ice, free !

Updated 2025-01-04

DMI is the Danish Meteorological Institute and the Open Data API provides free and open access to DMI’s data.They are covering a pretty big area not just Denmark.

I'm maintaining the weather station for Domstens yacht club and have become really interested in weather "issues".

The actual use case for me is that I have to change the mooring, of our boat, if the water level exceeds 60 cm from normal. For several years I have been searching for a free forecast API so I can get an early warning when the water level rises.

Node-Red is used.

AIS receiver and dispatcher ! The best ?!

Updated 2024-10-25

I found this amazing application, AIS-catcher, just scrolling around on Youtube and it includes "all" you need for an AIS receiver staying ashore or installed on a boat.

It is compatible with a wide range of Software Defined Radios (SDRs). These include RTL-SDR dongles (such as the ShipXplorer AIS dongle and RTL SDR Blog v4), AirSpy (Mini/R2/HF+), HackRF, SDRPlay, SoapySDR, and file/network input (ZMQ/RTL-TCP/SpyServer). 

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.

Bredbandskollen, Internet speed, CLI

Im using NodeRed together with Speedtest by Ookla but just the other day it wasn't showing the right data so it was time for "Bredbandskollen", the command line version.

Bredbandskollen has always been a reliable source when testing internet speed. I'm using their WEB-site and the iPhone app and it have always worked very well.

This post will show how to plot data in a graph according to the picture.

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.

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.

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 !

Raspberry Pi watchdog made simple

Updated 2023-11-08 for Bookworm !

The purpose of a watchdog timer(WD) is very well described here but a more practical answer is;

If your Raspberry Pi(RPi) "freezes", or hangs, it will automagically reboot within a very short time.

This is made with a combination of hardware and software which is all ready available, on the RPi, and just have to be enabled.

After some hours Googling and testing these are my findings !

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....