#murknorth — Public Fediverse posts

(smoke detectors) Okay, let’s write this down to think it though

The latest smoke detector to howl pointlessly into the night sends out 11.3V DC onto the signal pin when triggered but running off batteries. I suspect that’s 12V nominal, and it probably delivers 12V when operating on AC power.

Most importantly, it’s not like… 500mv. Or AC. Or complicated. It’s plain, simple DC.

When acting as a non-reporting satellite node, it triggers when receiving 4V DC on the signal pin (4.0 exactly), and that voltage is polarity sensitive. -4V doesn’t trigger the alarm.

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.

(Yes, I checked for AC as well. Still functionally nothing.)

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.

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…

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.

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

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’.

blinked out on me like a double-striped peppermint stick

Had a very surprising moment as I was going down the front stairs today to go out biking and two of the stairs disappeared out from underneath me, blinking out of existence like a double-striped peppermint stick

Of course they had not actually disappeared, it just turned out the fuckers who installed them used framing nails in an outdoor application and guess what they’ve been rotting out from the inside allllll along

(To be clear, the nails have been rotting out, the wood seems to be fine.)

Fortunately it was me and not any of the delivery people, my reflexes are pretty good and I just ended up sitting on the next surviving stair going “wha happen?!”

Pics at Mastodon if you’re into it

[link] #HomeEc #HomeEc #murknorth

northshore bike map release candidate 1

This is a link to my new Greater Northshore bike connector map, built to link the long-maintained Seattle and new Eastside 2 Line Rail connector bike maps. Since we haven’t had one and nobody else is going to connect the dots, I decided I would.

The partially-covered white map at the bottom left is Seattle’s; and the lower-down equivalent on the bottom right is the very top of the 2 Line Rail Eastside map. Everything else is this map.

If printed at 300dpi actual, the map is 24″x10.4″ or 608x264mm in size. It should fold down nicely if you’re into that sort of thing.

NEW IN RC1:

• Steepness markings, measured using Google Maps data and trigonometry, with the single- and double-chevron steepness indicators pointing uphill and scaled as per the 2 Line Eastside map.
• A couple of very small corrections

What’s not listed: trails on private property and some completely isolated islands of quasi-bike-lanes that go nowhere.

Corrections desired.

Finally, thanks to the other contributors to this map:

• Erik H on Facebook (Bothell additions)
• @[email protected] (Shoreline additions)

#BikeTooter #BikeMap #maps #Shoreline #LakeForestPark #Kenmore #Bothell #Woodinville

[link] #art #biking #BikeMap #BikeTooter #Bothell #Kenmore #LakeForestPark #maps #murknorth #northshore #seattle #Shoreline #Woodinville #worldData

surprise spring parts

Anna and I were getting ready to bike first to exercise then to go to the grocery and I noticed this metal ring on the floor of the garage and looked at it and thought, “uh, that looks automotive,” which was bad given it was next to Housemate Paul’s car.

Right where Bilbo left it

So I looked at it and looked at his car and […]

[link] #diary #homeec

Prototype 3.2: I never did write up a final report on the dryer heat recovery system, did I?

I never did write up a final followup report on the clothes dryer heat recovery system, did I? A writeup on Version 3.2, which I promised over a year ago when writing up Version 3.1.

Well: it works! It works really well, honestly. The house is more comfortable with a little more retained humidity in the winter but never gets at at all damp – […]

[link] #3dprinting #homeec #maker

the last paid project before layoffs

With Anna getting laid off/facing contract expiration, we’re pulling back hard on projects we’d hoped to do this year. But we did go ahead and order this last one, since it had been in the queue and was also not the sort of thing you want to leave forever.

So. The original owners some 20+ years ago built a smallish patio when they built the rest of the […]

[link] #diary #economics #homeec

100% live data

100% live data, folks. Got the new controller hooked up to the actual, real air-exchange system and we’re up and running. 😀

Semi-passive/air-exchange HVAC assistance system running against live data on real hardware. We’re in summer mode and it’s warmer outside than in – building composite temperature 22.0°C, outdoor 22.5°C – so the […]

[link] #electronics #maker #tech

goddammit printers

BEST THING: when your networked ancient but non-DRM laserprinter has been crashing on certain PDFs for months so you think there must be something new in PDFs and maybe it’s replacement time BUT

you discover your printer has room for RAM expansion so you check and it’s at minimum configuration so maybe it’s just running out of RAM […]

[link] #tech