posted on Feb, 22 2009 @ 02:07 PM
I can think of a couple of very rudimentary techniques that I suppose could have a chance of working.
1) Sprinkle talcum powder or flour or some other such powder all over your floor before you sleep at night. Any motion across it would disturb it and
hopefully leave footprints. (As you mentioned, this one wouldn't work if you had pets, or maybe even other people in your house)
2) The old tie a thin piece of thread across the doorway trick. Except maybe do it around your bed, a few feet outside of the perimeter? Then, when
you make up in the morning, if it's broken, you know something has been there.