To create a "pet alley" with the motion
detector, simply mount it up-side-down. The
viewing area of the MS is like headlights on
a car, they see straight out at the top and
downward at a 40 degree angle at the
bottom. If you mount the MS about 4 feet
off the ground, up-side-down, then it will
give you a 4 foot "clear zone" along the
ground for a dog, but will still pick up a
human walking thru. Be careful however of
smaller dogs or any dogs that may jump up on
furniture, like the back of a counch for
example, they will still trigger the MS.