"Don Y" wrote in message
...
IME, the photocells aren't worth their cost. They really only detect
things
that are ON the garage floor IN the path of the beam.

E.g., a kids wagon or bicycle typically won't trip the detector (the light
shines under or through). The same is true of vehicles (unless their
front
or rear axles are in the path.


I mounted my photocells about 2 feet off the floor. That way if I don't get
the truck all the way in it may see it. The garage is only about 2 feet
longer than the truck and I have to pull almost top the wall if I want to
get the door shut and maybe walk around the truck with the garage door
closed.

I usually have a push broom hanging on a peg board and drive the truck so I
just bump it to let me know when I am far enough in.