On Tue, 23 Aug 2005 14:40:45 -0400, "Percival P. Cassidy"
wrote:

Here's one for the electrical/electronics gurus.

Our new Wayne-Dalton iDrive garage door opener operates its associated
light fitting via an IR beam: the opener proper installs right above the
door, while the light fitting can be mounted to any convenient outlet
within "view" of the opener.

The light operated correctly when it was first installed, but then would
sometimes switch on but not be able to be switched off except by killing
the power to that circuit -- and even then the light would sometimes
switch on and stay on as soon as power was restored.

I called Wayne-Dalton Customer Service. The rep. asked whether we had
fluorescent lights in the garage. I replied that we did but that the
problem existed even when the fluorescents (CF) were turned off. The
rep. then said, "We have found that fluorescent lights can interfere
with infra-red sensors even when the lights are turned off." I told her
I couldn't see how that could be, but there was no point in arguing,
because she was only reciting her official spiel.

They are going to send a new light unit and a new motor-control board
(mine is an older revision, it appears), but . . .

Please tell me that there's no way a switched-off fluorescent can
interfere with IR circuits.

Okay, there's no way a switched off flourescent can interfere with
anything. Switched on of course is a whole nuther ball game,
particularly if the fixture uses an electronic ballast.

But in this brave new world where every doodad manufactured includes a
microprocessor, a switch-mode power supply and a wireless link, the
other possibilities are endless.

Someday everything will just come to a dead stop because the
electromagnetic spectrum will be nothing but hash.