DIY: Garage door open indicator

One morning a few weeks ago I got quite a surprise when I opened the door leading from our mud room into the garage.  The garage door was wide open, and had been that way all night long.

Never mind the tools, bikes, golf clubs, portable generator and all manner of  stuff that could have been stolen -  someone could have just walked into the house as we slept, as we don’t normally lock the door from the garage to the mud room.

I hate to say it, but this isn’t the first time this has happened.  It’s by no means a regular occurrence, but it has happened three or four times over the last few years.  So I began thinking of options for somehow being alerted if the door is left open.

There are battery powered wireless systems on the market, but the ones I found would signal that the door was open even if you left it open just a few inches for ventilation. 

I wanted a system that would alert me if we’d just plain forgotten that the door was in the fully raised position.  Also, if possible, I wanted the indicator to be as discreet as possible. We don’t need any more electronic gizmos sitting around the house… and certainly not in the master bedroom, where my wife even objects to the (fairly small) ooma Scout on her night stand.

I did find an article on a DIY system – I’ll link to it a bit later in this post – but the type of garage door in that article was different from mine.  The article did give me a wiring schematic that I could work from, so with that in mind I began inspecting my garage door for options for a switch of some sort.

What I discovered was that the top edge of the door, when in the fully open position, was right near the angle iron that supports the rails for the door.  As a bonus, there was a bolt that I could mount a simple bracket from.  So I headed to the local Radio Shack and bought $6 worth of components, stopped at the home center and picked up a doorbell transformer, 120 feet of two strand bell wire, and a couple of “L” or corner brackets, and was set.  My total outlay was about $40.

I started by reaming out a couple of the mounting holes on the larger of the two L brackets, installed a “normally open/momentary on” push button switch on the side facing the top of the door, and bolted the bracket to the angle iron support.  Here’s the installed switch, with the door stopped just short of being fully open:

When the door is fully opened, the switch is depressed, closing the circuit.  The bracket can be bent to ensure that the switch is fully depressed.  Here’s the door fully opened, and the switch is closed:

A bit later on, and the switch has been wired; I used some heat shrink tubing I had on hand to make sure everything around the switch terminals was sealed as well as could be:

Next I wired the 24 volt transformer directly to a grounded plug and located it right above a power strip near my workbench.  The heat shrink tubing (directly beneath the transformer) covers a 4.7k-Ohm resistor which was soldered in place:

Before we go any further, here’s a simple wiring diagram for the system.  The transformer I used was wired to produce 24 volts AC; the 4.7k-Ohm resistor knocks the voltage down to the point where a 2.8 volt LED can be used (you can click on this for a close-up):

I ran the wire up the wall, across the ceiling, and into the attic.  Doing this on a day when the outside temp was about 80°F did not turn out to be particularly brilliant, but once I had it in my head to do this, there was no turning back.

I originally thought I’d just put the LED on the wall of the mud room, but then realized that if I’d remember to check the LED, I’d could just open the door of the mud room and look at the garage door itself.  No, I needed something foolproof, preferably something in the master closet or master bedroom. And I couldn’t get away with drilling a hole in the wall of the master for a red LED; if I did that, I’d be posting this from a hospital bed. She Who Must Be Obeyed would not be amused.

Looking around the room, I thought that perhaps I could put the LED inside the frosted glass on the ceiling fixture.  After thinking about it a bit more, I thought that idea inelegant; after all, every time that light was on, you’d see a shadow of the wiring and the LED.  It was then that I hit on the idea that I ended up going with.

I drilled a relatively small hole through the decorative trim on the light, orienting that point on the light toward the headboard of our bed. Anyone coming into our room would never even see the light, even if it were on, unless they walked over near the head of the bed.  And……  if you got in bed at night and had forgotten to close the garage door, there is NO way you wouldn’t notice the illuminated LED.  I was happy with this solution:  it meets my criteria and was, if I must say so myself, clever.

Here’s what it looks like (photographed during the day, of course):

The only mod I might make at this point would be to add another LED to the wiring in the garage – just I could glance at it once in a while as a check that the pushbutton switch is still being fully depressed.  (Of course, I can also look up at the switch after I drive into the garage, so I may not bother with this additional LED.)

Here’s the link to the original DIY article, written by Bill Grundmann:  Garage Door Indicator.

I hope you enjoyed this post; please comment if you have questions or have worked on similar projects.