Hi all,

I want to make a simple, cheap, quick, reliable (no one dare say you can
only pick only x) garage door open detector that will light up an LED in th=
e
house/beep a speaker if the garage door is open. I know all it takes is a
mechanical switch, but I'd rather not use any moving parts. I'm thinking a
very bright infrared LED and IR transistor with a piece of foil mounted on
the inside of the garage door. If the door is closed, a series of LED pulse=
s
will hit the aluminum foil reflector and bounce back to the IR transistor
and signal the device that the door is closed. Will this work? I've never
done any IR work, so I don't really know what power LED is required, what
the distances are, etc.

As for the micro controller unit, I can make it wireless and signal the
indoor unit via something like this
http://www.sparkfun.com/products/10534but I'd have to impliment
encryption on the micro controller itself. It
would also interfere with other units in the same band, which is very very
undesirable. How hard is it to implement simple encryption?

Xbee is cool, but it will add $40 at least to the cost of the project.

Any other ideas?
--=20
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