"Mike Ryan" wrote in message
...
On 21 Jan 2007 05:57:40 -0800, "cavedweller"
wrote:


Mike Ryan wrote:
Is it normal for falling snow to make a motion sensor turn the light
on, or do I just have a crappy sensor? It stayed on almost all night
from the falling snow until I finally shut it off completely. I just
bought and installed this unit a few weeks ago, so it's going back to
the store if it's just this particular brand or model. I bought this
thing to save electricity, not waste more.


Does it have a sensitivity adjustment?
If so, adjust it.
If not, you could get one that does.

There are 2 adjustments. Distance and Time.
I know the time only affects how long it stays on.

I dont believe the distance one would be considered sensitivity, but I
will try changing it. The manual is not very useful or detailed.


Distance = sensitivity.

The snow may not be causing the light to come on. Motion detectors work by
detecting a change in heat, and since snow is the same temperature as the
air, or very nearly so, something else is causing the light to go on. Maybe
gusts of wind are picking up warm(er) air from near a window or door, or the
sensor can "see" across the street and it is picking up cars. As someone
else stated, motion sensors are much more sensitive in the winter than the
summer. In the summer it may appear that it is not working at all, if you
want to detect a person. (the body temperature being close to that of the
ambient air)

Keep in mind too, that motion sensors are most sensitive when the motion
they're looking for is -across- their field of view. If the motion is
towards or away from the detector, it isn't nearly as sensitive.