[HN Gopher] Whatever happened to IoT smoke alarms?
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Whatever happened to IoT smoke alarms?
Author : edent
Score : 10 points
Date : 2021-04-10 11:38 UTC (11 hours ago)
(HTM) web link (shkspr.mobi)
(TXT) w3m dump (shkspr.mobi)
| brudgers wrote:
| They were and are a really fucking dumb idea.
|
| A smoke detector has exactly one function.
|
| Make really irritating noise whenever something is wrong.
|
| And exactly two definitions of wrong: smoke and low power.
|
| The incorporation of convenience features entirely defeated the
| purpose of smoke detectors. It made them less likely to save
| lives.
|
| There are still IOT smoke detectors in the commercial space for
| air ducts. And instead of noise, they signal a monitored central
| station in facilities in working relationships with the local
| fire service. Hospitals for example.
|
| That's not your house.
|
| The limited life expectancy of smoke detectors created an
| attractive recurring purchase model for Nest. It over-ruled life
| safety effectiveness. I suspect, but have no evidence beyond
| circumstantial, that lawyers, regulators, and insurers all said
| things that made financial accountants remodel projections.
| heisenzombie wrote:
| I dunno, I don't see a problem with progressive enhancement of
| a dumb device: Clearly, don't control the screecher with a web-
| connected microcontroller. But if it's a totally standard dumb
| fire alarm that also outputs a voltage to a microcontroller
| that sends an alert to your smart home platform of choice? I
| don't see the downside. And if it has a 90% chance of alerting
| you that your fire alarm has gone off when you're out of
| earshot of the irritating noise? Why not?
| seized wrote:
| I disagree. My dumb detectors started false positives after
| just a few years. Their mute/silence buttons didn't work so
| burnt toast meant two minutes of screeching. No options for
| remote alerts (without external smart hardware). Batteries
| would only fail at night even after a few years. Or dust? Or
| carbon monoxide? Never knew, because the beeps were a terrible
| form of communication.
|
| Smoke detectors SHOULD have some safe, reliable smart
| technology. All my Protects have outlasted the simple Kiddes.
| nojokes wrote:
| I like the second kind of wrong. My smoke sensors start to make
| random short bleeps. I have about 10 of them in our house.
| Usually it will take at least annoying 15 minutes to locate the
| culprit.
| [deleted]
| seized wrote:
| Nest Protects are still around and are amazing. So much better
| than the garbage Kiddes I had before (a working mute/silence
| button? What a concept!). The self tests and green Ok light at
| night are comfort boosters. And the voice announcement of the
| alarm level and location are great features.
| LatteLazy wrote:
| This is what I came here to post. So easy, so much function,
| even with rechargeable batteries.
| lights0123 wrote:
| https://www.consumerreports.org/cro/news/2014/04/when-to-rep...
|
| > The life expectancy of smoke alarms is generally 10 years,
| after which point their sensors can begin to lose sensitivity.
|
| Every website says they should be replaced every 7-10 years
| anyways, regardless of their smart-ness.
| toomuchtodo wrote:
| They have a very small amount of radioactive material (~1.0
| microcurie of the radioactive element americium-241) that is
| used as part of the detector, and it does what you'd expect it
| to do: it decays.
|
| Consumer Reports can and should do better being a bit more
| verbose for correctness.
| Crosseye_Jack wrote:
| A lot of them these days are photoelectric. They have a
| "light sealed" chamber (basically vented in such a way that
| ambient light doesn't have a path into the chamber but
| "smoke" does (well smoke, dust and other airborne particulate
| that is carried in the air)). Instead in the chamber you have
| a light source and detector. Light is emitted from the
| source, reflects of the side of the detector and onto the
| detector. (Actually, thinking about it, I'm sure that they
| can also work "the other way round", so instead of
| particulate blocking the light, lowering the detection
| levels, they can configured so the light source isn't
| pointing at the detector and use the reflectivity of "smoke"
| to relect light onto the detector. But you get the idea. It's
| been far too long since I've taken one apart, time to order
| another for fun. Anyways back to the post)
|
| Dedicated ICs for this purpose can detect the slight lowering
| of light detected over time by the receiver as dust
| accumulates instead the chamber and adjust its trigger levels
| accordingly.
|
| Removes the need for need for the scary radiation source
| warning label, removes the issue with the radiation source
| decaying over time and I'm sure comes with that lovely side
| effect of lowering the BOM cost.
|
| Even though LEDs also decay, as it's duty cycle is no where
| need 100% and is completely controlled by the IC I would
| expect the components in a photoelectric smoke detector to
| last much much longer than 10, but mine still came with
| (iirc) a 10 year expiry date on them. I would say because
| it's a safety device, an abundance of caution is applied so
| other things ageing out have to be considered too (like the
| power supply caps)
|
| Big Clive has taken these apart many a time. If this one
| doesn't cover the operation of them, just search for smoke
| alarm on his channel and I'm sure it won't take long before
| find one where he "tears down" the smoke detection chamber of
| an photoelectric version. https://youtu.be/uzKAZCKjpU8
|
| No idea off the top of my head on how heat detectors (best
| near your kitchen so your toast doesn't trigger them) work as
| personally I've never taken one of them apart (yet).
| [deleted]
| yftsui wrote:
| Zigbee smoke alarms cost is okay, but still a few bucks more and
| it add up if you have 10 of them.
|
| I just enable Alexa to listen for smoke alarms and send me a
| notification when I am away.
| dustinmoris wrote:
| > Could I build my own out of a Pi and some scavenged components?
| Sure - but I can't be bothered
|
| More importantly, no insurance company will cover costs from a
| fire if they find out that you had a self built smoke detector
| which didn't pass standard quality checks. I think in the UK
| landlords must do a yearly smoke detector check as part of home
| owner regulation so a self built device might have failed at that
| point as well.
| yetihehe wrote:
| Does it have to be wifi? My company makes GSM smoke detectors, no
| wifi required (and sim card with connection included in price).
|
| https://ferguson-digital.eu/produkt/gsm-smoke-detector-fs2sd...
| the_only_law wrote:
| I've read about all sorts of alarms (I don't think smoke, but
| fire and other emergency alarms) running on things like ISDN
| before the term IoT ever existed
| toomuchtodo wrote:
| Will this work in the US with a US SIM card?
| yetihehe wrote:
| We didn't test it yet, but probably not. In UK (where the
| author of article resides) yes. Sim card is soldered in.
| toomuchtodo wrote:
| Please consider the US market for future iterations (and a
| SIM socket if it's a reasonable price on the BOM). I
| believe Twilio even offers a global SIM with reasonable IoT
| data rate pricing.
| yetihehe wrote:
| It was more about space, it's small module inserted into
| that big detector. We would probably just make different
| module for US. Worldwide module is in planning stage
| after nb-iot takes off more widely.
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