I admit it, I’ve left my garage door open all night… a few times. Doing so leaves all of my precious spare parts exposed for the taking! And maybe more importantly, provides access to the inside of my house…. not a good situation. I’ve been thinking about making some sort of indicator (inside the main house) for when the garage door is open. This would alert the home owner (me) that the garage is open.

After thinking about it for a while, I believe I came up with the simplest way to do this….

When the garage door is open, the door trips a normally-open momentary switch, which then completes and AC circuit to a 4.5vdc wall wart. That wall wart powers a bank of LEDs that are installed in the house. Occupants of the house are then told if the door is open or closed.

Here’s a diagram:

Everything but the LEDs are mounted inside a project box that is zip-tied to the garage door guide track. The metal tab on the switch was bent in a u-shape so that it flexes, allowing for some forgiveness in positioning the unit on the door track. I decided to keep the switch on the AC-side of the wall wart so that the wall wart wasn’t always consuming power when the door is closed (which it is most of the time).

The LED light is placed on top of my kitchen cabinet and is not visible when it is not illuminated. However, it is very visible when it is on. You can’t miss it during the day or at night.

All parts were available in the parts bin at CTH or in my basement…. so total cost = $0. Time… maybe 2 hours.