I don't know

So, thinking I'd have an earlier night than usual, I went to bed.

I wasn't asleep yet when I heard beeping. Like an alarm. At first I thought, "wait, I just emptied the dehumidifier" but then I realized it had to be something else. I got up and at first thought maybe it was the CO2 alarm, but no. I realized (directional hearing) that it was the smoke detector.

It wasn't the "feed me new batteries" chirp, it was the alarm. I stood there for a moment, looking around: there was no smoke, there was no smell of burning. I haven't put the furnace on for the fall yet so the only "combusting" appliance going is the hot water heater, and that seems fine. No evidence of an electrical fire (that is a big worry of mine...I try not to overload the circuits).

I took the thing down and pulled the batteries. A malfunction, maybe? I didn't know what to do.

Of course, by now, I was fully awake again.

I put the batteries back in and tested it. It seemed to be okay, and I stood and stared at it for a few minutes to watch the "one blink a minute" of the LED that says "it's functional and everything is okay).

At first I was just going to set it on the bathroom counter rather than trying to reach up and screw it back in to its mounting, but then I thought (late-night thoughts): what if there really were a fire tonight? You wouldn't be alerted to the smoke until it's really bad. So I reached up (I was NOT getting the stepladder out at that hour) and managed finally to fumble it back into place (It is about 6 1/2 feet off the floor, maybe a bit more, the absolute limit of my reach)

Then I took it back down. What if it went off again? What if something really WAS wrong? I know you're supposed to clean these regularly but I don't keep canned air on hand (you can blow the dust out of them). I sort of shook it gently.

At that point, a tiny (like 1/8") wasp-like insect fell out of it. I didn't think much of it then, but later wondered if THAT could be the cause of the alarm triggering - obviously, it was nothing, because my house is still intact and fine this morning, and the alarm didn't go back off in the night.

And I remember, shortly before they moved away from the house in Ohio, my parents had a problem with the (hard-wired) alarm system - they spent one night trading off time in the basement, where the control panel was. The fire alarm would periodically go off and it was LOUD - in fact, it was audible outside the house (it was set up to automatically call the fire department, but I guess the idea was an alarm going off might alert the neighbors that help was needed?) They knew nothing was burning in the house, but the alarm kept going off....and then my mom figured out if you sat near the control panel, you heard a tiny "click" right before the alarm went off, and you could hit the "reset" button and stop it - so, as I said, they spent the night (and part of the next morning, until the tech got there) doing that. (Apparently my suggestion of "tape down the reset button" didn't work)

Anyway, when the tech got there, he was like, "Yeah, we see this from time to time" and took the housing of the sensor off, cleaned out a spider and its web, and left a bill. The spider moving around in there somehow made the thing sense "smoke" and go off. So I'm wondering if the tiny wasp in mine did the same thing.

I will say - I should change the batteries when the time changes. Even though mine does a chirp when the batteries are out it's probably good to change them once a year anyway. (And I need to get a new one for in my bedroom; the one in there is over 10 years old and I don't even know if it would go off, and with all the white-noise machines I run, if I were hard asleep, I might not hear the one out in the hall)

But it took me a while to relax again and go to sleep.