I've been looking for this video to show you for a long time, and I finally found it, it's an episode of MythBusters that I saw some time ago, in which one of the myths to be hunted caught my attention, and it was the one of the myths of the ultrasonic motion sensors. Watch the video and you will see why it caught my attention:
As easy as you can see, with a simple sheet.
English 
Spanish
You have to sit on the edge of the seat, trying to put as little weight on the seat as possible. My father is a tachero and we used to travel that way everywhere. Good luck!
hola soy enmanuel y me gusta mucho inventar necesito un plano de un sensor de movimiento
hello i want to know how to mock a taxi sensor that marks the trip when a passenger gets in that are laser.