sean d'epagnier edited this page Nov 29, 2017 · 7 revisions

nmea0183 weather sensors are supported. A variety of sensors should work provided that they output $xxMWV

nmea0183 MWV messages encode both wind speed and direction used by the autopilot

I have a simple arduino-based nmea0183 receiver. It integrates bmp280 data over i2c with anenometer (davis vantage anenometer) This anenometer uses 4 wires:

  1. red - gnd
  2. yellow - 5 volts
  3. green - wind direction (potentiometer from 6 to 354 degrees) There is typically a 13 degree "deadband" directly into the wind with a single-brush potentiometer.
  4. black - wind speed (momentary switch closes and opens for each rotation of cups)

It would be possible to use any anenometer which is based on a potentiometer to measure wind direction using this sketch.

Pictured above, the arduino-based weather sensor.

Pictured above, the weather sensors in OpenCPN Pictured above, the anenometer unit mounted to the back of my boat.

The above weather sensors read analog direction from a potentiometer and wind speed from a pulse generated from a magnet passing a magnetic reed switch. The resulting wind speed and direction is displayed on the screen as well as transmitted over the serial port.

A short video demonstrating the lcd display:

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