Archive for the ‘The Doppler Effect’ Category

The Doppler Effect

Wednesday, July 18th, 2012

So you thought “The Doppler Effect “was only a throwaway term used in The Big bang TV series

 The Big Bang

High frequency occupancy sensors uses ultrahigh-frequency radio waves, also known as “microwaves” and the principle of the Doppler Effect to detect motion. 

The sensor sends out radio waves that bounce off of nearby surfaces and return to the sensor. Motion in the area changes the speed of the waves returning to the sensor. The sensor detects the change and interprets it as occupancy. This causes the sensor to turn ON the load.