At 05.16 2011.10.12, you wrote:
>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 t=
he
>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 puls=
es
>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?

I was faced with the same problem too: after investigating and trying many
solutions, I went with a magnetic solution. Attaching a magnet on the garag=
e
door was easy (as it's ferrous).

In my case it calls me on the phone..

Regards,
Mario

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