I use to use the old "Breathalyzer" as a lie detector. When you turned it on the system had to be purged of old air and new air sample was tested.

DUI suspect was told to blow in the tube until the rods on top rose out of the machine and it buzzed. This happened every time no matter what.

A well known but stubborn burglary suspect was told this is a lie detector. I'll ask you a question and you answer. Then you blow in the tube.. If the rods rise it indicates you are lying and if it is a bad lie the machine will shock you when the rods reach the top.

Suspect blows, rods rise, suspects eyes get big, Keep blowing!! Rods continue to rise, eyes get bigger and machine buzzes. Suspect jumps back and throws the tube away.

See, we know you're lying, now let's get to the truth. Pick up the tube..... interview continued and stolen property was recovered.