Measuring air flow in an HVAC duct can be a tricky business ... The principle behind the sensor [ItMightBeWorse] is working on is nothing new. He discovered a paper from 2015 that describes ...

Take your time removing the sensor. Parts are plastic. They become brittle over time and can break. Slid out of the duct.

His experiments in air duct flow measurements, which previously delved into ultrasonic flow measurement, led him to try mechanical means. That calls for some kind of turbine producing a signal ...