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My neighbour left their garage door open overnight and lost some valuables in the process. I was thinking there must be a cheap circuit I can build that could detect when the garage door is open and illuminate a small LED in the house.

Besides constantly opening the garage to check it's closed, I was thinking I could build a small ciruit with the following items:
* Reed switch ( security window switch)
*12V DV power ( old cell phone charger)
*LED lights
*wire (18 gauge?)
*Resistors ( attached in series to the LED's)

I want to mount the LED light inside the house. Anytime the garage door is open, the LED would illuminate. The Reed switch would be mounted on the edge of the door and the other side would be mounted on a piece of angle iron. When they are in contact, the light would illuminate indicating the door is open.


Has anyone assembled something like this for their home? I'm not sure how to calculate the size of the resistor for the LED. Any help would be appreciated. I think I can make this for under $10.
 

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Sorry I can't help but that's something I sure could use.

EDIT: Just checked Home Depot and they sell one for $27. I think I might buy one!
 

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Sorry Plasma1, should not have taken your thread off-topic.

Back on topic please.
 

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Plasma1,

I think i found a post on instucables of someone creating almost like what you want.
Here is a quote of his supplies:

Ever left your garage door open overnight? In addition to being a terrible energy waster, all the tools, bikes, and other stuff are available to thieves - who might even enter your home via the door from your garage to your living quarters.

Install a simple indicator which will alert you if you've left the garage door open. Total cost is less than $30-$40, and you can determine exactly where the indicator will be located.

What you'll need:

Components:
-A 24 volt doorbell transformer
-1 push button "normally open/momentarily closed" switch
-1 red LED - 2.8 volts
-1 4.7k-Ohm resistor (specific part numbers for the electrical components are provided in Step 2)
-2 strand bell wire
-Electrical tape and/or heat shrink tubing

Tools:
-Wire strippers
-Soldering iron + solder
-Electric drill
-Misc. hand tools - wrenches, etc. - depending upon the specifics of your installation
http://www.instructables.com/id/How-to-install-a-quotgarage-door-openquot-indi/?ALLSTEPS

All instructions are on the link
 

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I'm a fanatic about the closing the the garage door, and watching it close completely, after a theft at my brother's place. The doors will often reverse if any obstruction, snow or animal or if someone else uses it after you leave. I also unplug when I'm going to be away for any length of time.

One problem with the indicator light is if you are not there to see it, you still don't know if your door is closed or not. Maybe something like this that would close the door if anyone leaves it open would be a better solution?
 

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Use a standard 560 ohm resistor (http://led.linear1.org/1led.wiz)

A couple of thoughts. 18 AWG wire is overkill. 22AWG telephone wire is adequate.

Consider using a proper overhead door contact since that will typically gave both the large gap specification and the offset mounting bracket at you will need.

Remember you'll need a Form C contact to get the normally open cct. Otherwise you're LED will only light when the door is closed.

Finally, if you're going through all the trouble, run a second pair of wires so that you can also have a switch to operate the door opener,
 

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I would get a ready made LED marker light (the kind made for trailers). Go to Princess Auto to get one or more.

You would have a flatted lever microswitch mounted to the opener track or door track, in a way the lever is depressed when the door is closed.

Use the NC contact on the switch. Use two wire thermostat wire. That at least is in-wall rated.
 
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