On Mon, 16 Jun 2008 12:08:42 -0500, with neither quill nor qualm,
Randy quickly quoth:

My shop has no windows so on nice days I like to keep the overhead
door open. Well some kid watched me welding for awhile then decided
it was safe - snuck in and stole my laptop computer that was connected
to my CNC mill.

Got him on video, filed a police report.

Excellent!


I need some kind of photocell and beam across the doorway to alert me
if anyone walks in. Can garage door safety beams be used? I have a
couple of friends that can wire up or build me a circuit to make them
work, I just don't know how the work, is there a NO or NC output on
those? I was told you cannot just jumper them out, so I'm thinking
it's more like a signal output rather than a switch closure output.

That could work, but it could be easily sidestepped by lifting your
legs over it.

I have these X-10 systems for my entryway:
http://www.x10.com/security/sc546a_s.html Scroll down to the set,
consisting of the chime, EagleEye IR detector, and RF transmitter.
$45 + s/h. (less on eBay)

And I saw this $20 special in the recent HF ad:
http://www.harborfreight.com/cpi/cta...emnumber=93068

Put 2 strips of tape over the right and left edges of the IR detector
to limit it to a narrower area of detection. It will cover the full
height of the garage door automatically.

--
The only way not to think about money is to have a great deal of it.
-- Edith Wharton