NMEA2000 for NASA / CLIPPER Duet sonar/log

Fig.: NASA/Clipper Duet Sonar/Log

This article is about how to convert a NASA/Clipper Duet echo sounder/log so that the device outputs NMEA2000 data. This document is based on the DIY project by Sönke and was supplemented with some additional information. The NASA/Clipper Duet echo sounder/log is actually a device without a bus connection and works independently with two separate sensors.… Continue reading

Maritime Data Server (MDS)

Fig.: MDS dashboard

The MDS – Mmaritime Data Server was developed to store and display boat data.

Which data can be saved?

During development, emphasis was placed on having a system that was as flexible as possible. The MDS is currently prepared for temperatures, voltages, GPS values, pressure and humidity, digital values, etc. Further data can be created by defining sensor types in the database.... Continue reading

Create maps for Garmin devices

Garmin GPSmap526 (Garmin)

Garmin is one of the few commercial manufacturers that also allow the use of public free maps on their devices. This makes it possible to also provide older devices with up-to-date map material when support has expired. Garmin offers a variety of navigation devices that can be used on-road for street navigation as well as off-road for tracking.… Continue reading

Create offline maps with MOBAC

Fig.: Mobile Atlas Creator (MOBAC)

mobile A.tlas Creator (MOBAC) is a Java open source program that provides offline maps for various navigation devices. As a source for an offline map, Mobile Atlas Creator can use a large number of different online maps, such as OpenStreetMap-based maps and other online map providers. In addition to pure navigation charts for vehicles on land, charts for watercraft are also offered.… Continue reading

Magnetic compass for SignalK

Fig.: HWT901B-RS232 9-axis sensor

The Chinese company WIT motion sells various sensor modules on the Internet. In addition to 3-axis, 6-axis and 9-axis modules, pure magnetometers are also offered in a wide variety of designs. A large number of interfaces are supported such as:

  • TTL
  • RS232
  • Modbus
  • Bluetooth
  • WiFi

A particularly interesting sensor is the HWT901B-RS232. This is a 9-axis sensor as a military variant with the following properties:

  • 3-axis acceleration sensor
  • 3-axis gyrometer
  • 3-axis magnetometer
  • BMP280 environmental sensor (temperature, air pressure, humidity)
  • 32Bit CPU for 9-axis sensor fusion
  • Accuracy roll, pitch: 0.05°
  • Accuracy heading: approx.
... Continue reading

Sail Instrument Plugin for AVnav

The idea of this AVnav plugin is to display an instrument that contains all the basic information needed for sailing. With the possibility of showing this display directly on the map at the boat position, the sailor has all the information at a glance. The laylines tell you the quickest bearing to a waypoint upwind, and when they are shown on the chart you can follow those lines.… Continue reading

Anchor light automatic with Shelly 1

Fig. Shelly 1

Anyone who anchors is obliged to set an anchor light so that you can be recognized on the open water surface in the dark. Typically, the light is switched on manually at dusk and off again at sunrise. There is no problem switching it on. But often you forget to switch it off and the anchor light is then permanently on and consumes electricity unnecessarily.… Continue reading

Lilygo T-Watch 2020 with connection to SignalK

Fig. Lilygo T-Watch 2020 (Lilygo)


Jan Dytrych has started a software project to be able to display data from SignalK and receive alarms with a smart watch. Not just any common clock under Android is used as a smart watch. He uses the smart watch Liligo T Watch 2020. The special feature of this clock is that it has an ESP32 installed as a processor and can be controlled via the Arduino IDE or… Continue reading

Magnetix - a digital compass with NMEA2000


I've always found the idea of not only showing the course on my plotter when the boat is moving, but also when it's bobbing along quietly, I've always found it exciting.

After searching the I-Net for different manufacturers, it quickly became clear that I might not need an e-compass on board at current prices.… Continue reading

qtVlm navigation and weather routing software

Where the name qtVlm for the navigation and weather routing software comes from is not known. In any case, qtVlm is worth a look for those who are looking for a freeware navigation software with basic functions. Depending on further wishes, the software can be expanded with add-ons that are subject to a fee. If you need it, you can also book telephone or email support for a fee.… Continue reading