We have just moved into a new house with an attached garage. It’s been nice weather so we have been leaving the door open. However we have forgotten to close it when we go to bed at night. We live in a fairly safe neighborhood. We should just check to see if its closed each night but I thought I could do something to indicate that the door is open. Any ideas about how to wirer a sensor to the garage door that would turn on a light when it is open and turn off when it is closed. Someone suggested wiring it to the light that comes on when the door opens however it turns off after a short time.

There are a number of ways you can do this but it depends on your knowledge of electronics and wiring. A simple magnetic switch at the garage door could be used. Using a magnetic sensor that is OPEN when the two magnets are aligned means no signal will pass through until the door is lifted and the magnets are no longer lined up. At that point your signal would run from through the contact and back to your device.

Essentially you can take a small low power light and run the ground line down to the magnet switch and then back up again to the light. When the door is closed the ground does not make contact and the light does not come on but when you open the door the circuit is closed and the light goes on.

If you were to make something yourself it would be done somewhat like this but there are products you can buy to do this also.

Look at this link:
http://www.smarthome.com/7311gd.html

I have seen garage door open indicators at either Depot or Lowe's. They ar probably very similar to what the night owl suggests.

Just did a quick Google and found several links to just what you are looking for (as well as a link to this question! )

Dan

You might check what voltages are present at the switch that signals the door to stop when it is clear up. You could wire it through a resistor to an LED somewhere in the house.

I have mercury tilt switches connected to the latches of my fence gates. They are wired to a red and green Led by the back door. If the gate is open, a red LEd flashes. It both gates are closed, a green one is on.

If you want to do something like that, I can help you with the details.

How do I wire a garage door with a becon to come when door is open