garage intruder, ghost, or lighting malfunction?

[SUPERFORD]

My detached garage has one deadbolted personnel door and two metal garage doors. All doors are within view of my house.

About 4 months after walking into our kitchen at night, my wife came and told me, "Someone is in your garage, I just saw the inside lights on and then go out!"

I don't have anything of value in the garage, but I don't much relish the prospect of an intruder in there either.

I get a gun and a flashlight and go outside to investigate. First shining light through the windows on the garage doors, then entering and turning on all of the lights.

I carefully checked the entire garage, under work benches, in the bathroom, and even in the attic.

Nothing.

I wrote it off to my wife either being crazy, or her seeing a reflection from the lights on the back of the house in the garage windows.

Until... a few nights ago I was standing at my kitchen sink looking out into the darkness and noticed that the lights inside my garage were on! And as I was looking I saw them go out!

Knowing that I've got a motion sensor in the garage, I sat and waited to see if whatever had turned the lights on, would move and turn them on again.

Nothing.

So my question is this... "What the heck is causing my lights to come on in the garage when nobody is out there".

I have Liftmaster door openers with this type of wall mounted controller:

they have a motion sensor that turns on the lights as soon as I enter the garage. But in both cases, the door was deadbolted and there was nobody in the garage. No animal, nothing.

Could one of these sensors be malfunctioning, or could something as small as a bug trigger these sensors?

I should note that at night the screens on these controllers are illuminated in a kind of "indi-glo" blue backlighting on the display screen.

I guess my only theory is that this faint light could attract bugs to the motion sensors (which are mounted right below the display screen)?

any other ideas or suggestions?

Thanks,
chris

 

[chrism0107]

rats?
just a thought.

 

[2manytoyz]

Power bump. My garage door opener also has a motion detector. If I walk into the garage, the light on the opener comes on. Great feature. No fumbling for the main light switch in the dark.

The downside is this circuit is VERY sensitive to any fluctuations in power. The lights in the utility room inside the house, but on the same circuit as the garage, will sometimes trigger the garage light if they are switched on/off.

It's really not that big of a deal, and doesn't occur all the time. It took a while for the planets to align and figure out why this was happening. Saw it happen on a security camera, and have been able to repeat it.

I'd be willing to bet it's the same deal for you. A overly sensitive lighting circuit.

 

[Blk88GT]

Mouse?

 

[JakeKohl]

Most of these motion sensors actually detect a change in the heat variation within it's sight - they're not actually just seeing "motion". For instance, when you walk within range of the motion detector, it sees the contrast between your warm body and the surroundings and sees your warm spot move through it's field of vision. It then triggers whatever system it is connected to when it sees the heat field change. Rapid temperature changes on stationary objects can also trigger the sensor.

Is it possible you have something warm in the garage that is cooling or heating rapidly or vice-a-versa? A heater or air conditioner within it's field of vision perhaps? (most of these garage door motion sensor designers don't anticipate a heated/cooled garage).

Second idea is the aforementioned rodent.


PS - a neat trick is to take a flannel blanket that's normalized to the ambient temperature. Hold it in the air so the "motion" sensor can't see any of your body. You can walk by the sensor all day and night long and not trip it because it can't see your body heat through the blanket.

 

[Falcon67]

Possible defective motion sensor. I've tossed one exterior motion light because of this out of 4 installed just last year. Last night, I accidentally switched off the outside lights. I waited about 2 minutes and switched them back on. All but one when through it's startup routine like normal. The one came on, went off, stayed off one minute, came on, switched off, stayed off one minute, repeat. Shut them down, let them sit about 30 minutes, turned on - after about 5 minutes that light started the BS again. I shut them off overnight and turned them on this morning in the light, so we'll see what it does tonight. I expect I'll be buying a sensor.

 

[nehog]

Is that motion sensor wireless or wired? If wireless then any radio interference may cause the lights to come on for a short period of time. I've a similar setup in the house (where I can turn off a lamp in the living room with a device that looks like a remote car fob) and that light about once a week will blink on by itself.

 

[happy2rv]

I have the same control panel on a Liftmaster 3800. I just installed it and am still getting to know the features, but I was working on the overhead lights not connected to the opener last night so I had the breaker for them off and used the lights from the 3800 to see what I was doing. Unfortunately, they would go off every couple of minutes and I would have to climb down the ladder and move in front of the sensor to activate them again.

I came inside afterwards and looked at the manual. The controller is programmable to disable the motion sensor, or set various on times up to 4 1/2 minutes. I believe it said you disable the motion sensor by holding down the work light switch for 10 seconds. You might try disabling it and see if they still do it.

If your opener is the 3800, the lights are wireless remote controlled. So, they could be set off by other interference as well. However, the motion sensor is the most likely culprit.

 

[Gary S]

Mouse?

Yep. Motion sensors aren't very reliable, but mice are.

Mice have no electronics so they work better.