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:

Pushbutton switch - open position

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:

Pushbutton switch - closed position

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:

Switch in place, wired

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:

Transformer in place (wired to 24 volt setting)

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):

Wiring Diagram

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):

LED installed in trim on ceiling light in BR

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.

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14 Comments on DIY: Garage door open indicator

  1. Kevin M says:

    Very cool, we have a similar set up as you do – mud room door to the garage that we don’t lock – so this might be something worth installing. My only issue would be our master bedroom is on the 2nd floor and would be hard to run the LED all the way up there.

    I was actually thinking about this issue the other night b/c there is no way to see our garage door from inside the house without opening the mud room door and looking into the garage. A solution I thought of was putting a rear-view mirror on our front porch that would allow us to look out the front window and see the garage door’s position from the comfort of inside the house (either our front living room or foyer next to the stairs leading to the 2nd floor).


  2. Bill says:

    You can also do this, and reduce the amount of wire, via X10. Use a normally open magnetic alarm sensor (difficult to find, but out there) and a x10 universal dry contact module in the garage, and a X10 light module in the house. When the door is open, whatever is plugged into the light module lights up.


    Kevin Reply:

    Bill: Thanks. As I see it, X10 = ease of installation at greater cost; bell wire = PITA installation, lower cost. I’ve seen the X10 stuff and it looks neat. Thanks for commenting!



  3. Alan says:

    I like this solution. I have installed the wireless variety, but when the battery in the transmitter gets weak, it is a pain to get a new one and replace it.

    I am not skilled with creating circuits, so I ahve one question. We have two garage doors. I’d like to install two LEDs. I think I figure out how to use the same transformer, but I want to confim that this is possible.


    Kevin Reply:

    Alan, Thanks for commenting! It’s no doubt possible, but I’m not certain how draw the schematic. Simpler would be one LED, with two swtiches wired in parallel – one on each door, of course – this way the LED would illuminate if either door was open (or if they both were open). If that solution wouldn’t work for you, please consider posting your question over at Instructables; I’m sure someone would be able to address it. kc


  4. Alan says:

    That is a great idea, Kevin. It would work perfectly. Now I just have to figure out how to run that wire from the garage to the bedroom. Thanks for the great instructable.


  5. Fred says:

    This might not be for everyone but I will throw it out there. First thanks for the great write up. I plan on doing the install this week with a few twists and turns. I plan (as mentioned) to add the second garage door to the circuit. Also will use the Genie switches that send the open and close signals. I just buy two from Home depot. They never die. I will also use LED’s in two locations. One in our kitchen(which is off the mud room) and also above the front door. The the reason is two fold. If we are not in the area of the first light then we have to walk past the front door to go up stairs. It is in plain site when lite. The second reason is in case one of led’s blows out. I know they last a lifetime(blah blah). I have had many a led stop working in my car and why take a chance. I will have to wire them up in series (I think) to make sure that if one led does die the other will work. We leave our garage open most of the day so that little light will be on most of the time. Your thoughts on how to wire the two would be helpful.. Last comment is bringing the led up stairs. Many of us no longer use “house phones” land lines anymore. I have disconnected my phone and also the wires from phone company box. I have since used these wires (which are very nicely color coded) to run speakers through out the house. If you are the type that knows this type of wiring, I think you could find the correct wires near your garage and have have your wire issue to upstairs resolved. It would require you to connect those wires together at each phone jack,but that is no big deal compared to running wire upstairs.. Just a thought.


  6. Neat trick. I like it. I wish for a way to have the alarm rigged so that when the garage door is opened the parked car’s lights turn on and it’s horns blare and a copy of that video Macaulay Culkin uses to scare of the wet bandits in Home Alone plays in the background :)


  7. Richie says:

    I love this design and used your plan as the general idea for my indicator. I used the same transformer, but ran it at 8v (9.4 actual). I used 2 LEDs (one near the door, and the other wired like yours to the bedroom) and a normally closed micro switch with a roller on it. Attached to the top of the door itself is some bent aluminum bar stock that will depress the switch only when the garage door is fully closed. It works great! I have the parts, etc. that I used if anyone requests them, though they’re not handing at the moment. Thanks for the great idea!


  8. Errol says:

    Thanks for posting. I have a similar setup at home. I used magnetic alarm switches on the door jamb with a magnet attached to the door. I ran my wires inside the walls (I had to cut sheetrock and do some drilling) from the garage to the attic where the power supply is mounted. From the attic the wiring goes to the header over the master bedroom door directly below. I have two LEDs, one on each side of the header. I see the light on the way upstairs and if by chance I miss that, it will be in my view when I get in bed.
    I am currently working on a switch to warn me whenever I forget to put on the deadbolts on my front or back doors (which I have done a few times).


  9. Garrian says:

    I would suggest a Sentrol 2202A-L or equivalent Overhead Door Contact. Search Amazon for a “Sentrol overhead contact.” They even make one that will mount to the track for the door. It is a magnetic wide gap contact made for garage doors. If you can, connect it to a burglar alarm so that it cannot be armed before the door is closed. This is my preferred configuration as I will arm the burglar alarm system before I go to bed. If the door is open, a fault will be present and prevent the system from arming.


  10. Leon says:

    I like Ritchie’s idea better. I want to know if the door is only partly open. I used a magnet on the side of the door and a reed switch on the door frame next to it. I used a 6V Adapter and a 1K resistor for the LED and a transistor to invert the N.C. relay to a N.O. when the door is closed. Also my LED is a blinking LED.


  11. Leon says:

    P.S. the blinking LED doesn’t need a resistor. NTE 3030 2.36 ea.
    Polarity sensitive. Flat side negative.


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