Does the knife under the door trick work?

Question

where you put the edge under the door to look and see who is coming, does it work? my doors are too low, it doesnt work for me.

Answer 1

Yes,...very well actually. CDs work a little better, because there is more area to work with, though.

We used it in a house we rented for a week to see what they hid in the doors they locked...good times :]

Answer 2

reflection is reflection :) of course it works. You can also get  some Fibreoptic cams and heartbeat sensors. Those really work, and dont leave you laying on the floor. The knife has the added ability to skew the door, specially on the non hinge side.

Answer 3

Yes it can work as long as the knife is shiny enough to reflect images and you can get a good angle with the knife under the door. Watch "Signs".... or "scary movie 3" you will see the knife under the door trick.