anemometer venturi-effect pitot-tube windspeed airspeed-velocity airspeed ias mlab mlab-module measuring sensor


Differential pressure wind speed sensor with magnetometer.


This is an open-source hardware design, one of the modules from the MLAB labolatory system.

WINDGAUGE03A - Venturi tube-based anemometer

High-endurance venturi anemometer with minimum moving parts. Automatic estimation of direction to magnetic north.



  • Minimised number of moving parts results in increased durability
  • The Venturi effect allows accurate measurement in a wide range of speeds and is especially sensitive for common low airspeeds

Function principle

The measuring tube consists of an orifice, which increases airflow in the tube. The different speeds generate differential pressure, measured by an electronic differential pressure sensor. The same principle was used at the beginning of aircraft airspeed measurement. It is advantageous due to better sensitivity at low speeds than pitot-static tube.

The anemometer consists of the IMU sensor ICM-20948 which contains a magnetometer, gyroscopes, and accelerometers. The IMU allows sophisticated data acquisition for failure detection and gust wind analysis.

WINDGAUGE03A schematics

Main parameters

  • Absolute azimuth accuracy 1° (to magnetic north)
  • Wind speed measurement range 0-120 km/h
  • Maximum mechanically safe wind speed 150 km/h
  • Communication interfaces:
    • USB
    • I²C
  • Operational temperature range -20/+45 °C
  • Maximum hail diameter 2 cm

Software installation

The anemometer uses pymlab software toolkit to interface with a station computer. The toolkit also contains an example which allows basic calibration and data recording of anemometer data.



The anemometer should be calibrated before the first use. That ensures, the calibration of magnetometer parameters. To correctly determine the wind direction by using an internal magnetometer.

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