Mastodawn

Checking for DC on the signal line, I get functionally nothing. 20ma DC at most, and even that's something I'm picking up out of noise floor shift rather than direct measurement.

My _thought_ was that if the signal line was somehow floating in whole number volts (for whatever reason) than maybe somehow the right RF noise could kick it over.

The problem with _that_ is that I can now _also_ confirm that non-detecting units go off _exactly as long_ as a detecting device keeps saying it's detecting by putting voltage on the signal line. If that voltage goes away, so do the satellite alarms - and immediately.

And that's not what happens. We have to manually intervene and shut the alarms off ourselves.

(2/n)

The reason I paid meaningfully more than baseline for this particular set is that they report exactly which detector went off and why. That way, if it were the signal line somehow triggering the alarms, none of them would claim to be the originating unit; they'd all report it came from the signal backbone.

But they don't. There's always a unit claiming to be the active detector and it's always smoke (and there is *never* actually smoke), and none of them shut up until we shut off that unit, which sometimes seems to require removing it from power.

So today's afternoon check was basically just another way of confirming what we already knew, and I guess I've done that now, but...

(3/n)

All _that_ does is get us right back to where we started, which is, "we have alarm after alarm after alarm of different makes, methods (ionisation, photodetector), and models which just in this house are determined to go off randomly, usually but not always at night, for absolutely no detectable fucking reason, and then pass self-test just fine afterwards."

And no, regular cleaning - even weekly cleaning - does not help. I do _all the things_. None of it stops the problem.

(4/?)

If you're new to this adventure, I have heard this exact same story from _many other people_ at this point - though nobody I've talked to has said they've literally taken metres to the signal wires to verify that way.

Regardless, I know it is not just us.

What I've been told from others who deal with this is to RMA individual units that trigger randomly one at a time until you end up with a set that doesn't. And I guess that's what I'm gonna do, but

holy shit, team

holy shit

(5/6)

this is the opposite of fire safety

this is the opposite of how anything like this should ever work, I mean

what if all the RMAs are getting you are a set that won't go off even when they should?

but whelp

guess i'm gonna find out

'cause this sure ain't workin'.

(6/6 fin)

Andy L.5d ago

@moira Why not ditch the fancy smart system and get a bunch of battery powered smoke detectors?

Then whatever is haunted about your wiring won't be an issue?

They make 'em now with ten-year batteries. Which is the replacement cycle for smoke detectors anyway.

@apLundell I don't know that anything is haunted about our wiring. I do know that the whole _building_ is haunted by RF, and that's not just wiring. It's ambient.

Andy L.4d ago

@moira

Isn't that all the more reason NOT to be relying on long runs of low-voltage wiring?

4d ago

@apLundell Only if the RF is doing something actually directly to the circuit board through the low-voltage line which is making an individual unit think it is optically detecting smoke.

Which, I mean, I can't rule out, but... these are going to be built to expect that, right? And mains power is going to bring in more... though I guess mains do go through a rectifier and that's literally designed to convert AC to pure DC, so.

(Also potentially relevant - and something I've looked at a lot - is that it started with the large-scale switch from leaded to unleaded solder. At first, I absolutely thought problems with that process were the cause. But those problems got solved and units from 2024 are still doing it.)

Andy L.4d ago

@moira If it was the solder, it'd be a large-scale systemic issue and not just your building.

Most people are certainly not replacing smoke detectors on the regular.

(Except in the sense that they expire every 10 years and we replace them then. In theory.)

4d ago

@apLundell Again, as per the thread, I have talked with _many other people seeing the same issues_. There are replies _on this thread_ from other people who have seen the same thing.

It is

NOT

just this building.

The advice I've received from building managers (plural) who have run into this has been, "RMA units that go off until you have a stable set." And that's what I'm starting to do.

(1/2)