Finally I had time to complete the wind vane system on my sail boat. As I’ve mentioned in previous projects I am using a Peet Bros marine grade anemometer at the top of the mast. I managed to mount the new anemometer in the old existing ‘Signet’ brand frame, which turned out to be an excellent fit after cutting it down slightly.
The wind vane sends signals down the mast to an Arduino. The Arduino outputs the wind speed and direction via the NMEA 0183 protocol, which can be connected to programs like OpenCPN or to the iSailor app via WiFi.
The Arduino can then also be used to output signals to a B&G Network Wind display in the cockpit, giving a readout to the helmsman. This particular B&G display is an older model, and thus can sometimes be found reasonably cheap on eBay. I have also been informed by a reader that the Simrad IS15 wind display can read NMEA signals directly, providing an even easier option.
The system has been up and running a week now with no problems. The Arduino contains error checking and filters the direction output to smooth out quick variations. The direction offset and filter rates can be easily changed in the Arduino code.
The main costs:
So if anyone is replacing or adding a wind instrument to their boat, consider making one yourself! UPDATE: I have designed a small circuit board for this project which is available to buy on tindie. Alternatively for a small donation I can provide my code if you’d like to build one yourself.
Using the Peet Bros anemometer is not totally foolproof however. As I described at the end of this post, you may need to look into the signals it generates if it doesn’t work out of the box.