A pitot tube is a device that is typically found on aeroplanes and measures air speed, but as they can also be used to measure airflow within air ducts, they could have applications in HVAC systems, explains Hackaday.
Pitot tubes work by measuring the difference in pressure between an opening in the front of the tube and a side opening, but to do this accurately requires a microelectromechanical systems (MEMS) pressure sensor, along with knowledge of air temperature and absolute pressure, explains Frenk Kopač in a tutorial.
Kopač has made the design open source and available on GitHub, specifying the materials and microcontroller, and his tutorial also covers the best way to position the tube.
