Stupid design decisions

Yes, that's a real problem that I have also experienced. The very short chirp of a smoke detector, when it echoes off a bare wall or floor (I still have acoustical "oatmeal" ceilings in my house), can be harder to locate than you might imagine.

I used to have only one smoke detector in the whole house. It was easy then. When we remodeled two bathrooms, the city's code inspector came through and made us add a LOT of detectors. Including the carbon monoxide sensor, now I have nine of them!

What they need is a latching elctromechanical like I have on some RCD outlets, where by you have a small hole/window through which you can view something solid which has two colour labels like Red and Green so you can inspect if necessary with a torch.

That way even if the battery has died completely it can be SEEN if battery is OK or not on that unit.

You still inspect the however many but you

Don't have to wait for chirrup

CAn see if battery is completely dead

Can regularly inspect status

If clever enough can show battery fault because someone has removed the battery to satisfy inspection regimes.

Still have chirrup to say battery going but quicker to find the actual one.

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Paul Carpenter          | paul@pcserviceselectronics.co.uk 
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I think this would be a great application for a spot of eInk if they can make it cheaply enough. That stuff takes a bit of power to change, but holds its state for a long time with no power. It would only need a quarter inch square or maybe a simple logo showing the battery dead. A battery with the slashed circle over it would do I suppose.

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Rick C

There are also a number of smoke detectors that are (or can be) Internet connected. Many of those also avoid the need for wires to interconnect multiple detectors in a house.

That's gotta jack up the price. Isn't a smoke detector still in the $20 ballpark? I guess they can put a raspberry pi zero in for only $5.

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Rick C

The combination smoke+CO alarms seem to be more in the $40-60 range. The Nest Protect (smoke+CO+WiFi) is $99.

One of complaints about the whole IoT thing is not that I disbelieve people are going to put WiFi (or something) ports on the back of billions of items (I'm certain they are), it's that they'll be able to charge big markups for something like that. I'm pretty sure I won't pay $99 for a smoke/CO2 detector. So I suspect that we will have billions of IoT devices, but the average BOM for the "IoT" bit is going to be well under a dollar.

Hasn't Google essentially savaged Nest already? I just read a thing about it a year or so back and wrote the entire line off.

Yeauuuugh....

In quantity, there's no reason to think the prices wound diverge that much. It's just that the deployment case for IoT devices isn't that clear because you have to then have other infrastructure in place. Just putting the SSID on all the lightbulbs in the house sounds exhausting.

I know that for remote light switches, the IoT version is twice or more the price of just a non-IoT version, and you have to use a phone to run 'em. I have a few of the non-IoT remote light switches, and they are at disposable price levels.

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Les Cargill

The real issue there is the insistence that every IoT device MUST be Wifi !

I see enough issues with Wifi in houses not working or because three people are streaming they get buffering (partly due to low broadband speed). Often the heat efficient houses have foil backed dry wwalling (plasterboard), making each room into its own Faraday cage. Let alone the ones with stone walls a foot or more thick.

If you have a MAINS connected device don't use Wifi use the Mains wiring you already have to talk yo your base station.

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Paul Carpenter          | paul@pcserviceselectronics.co.uk 
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Because, what could go wrong?

They should, at least, continue to function as singleton smoke detectors even if all the connectivity is bollixed. Is that good enough? That's an interesting question.

When my house was built, the local building code required interconnected smoke detectors on each floor. They did *not* require battery power for the detectors. IOW, don't have a fire when the power is out.

IFAIK, the current code requires interconnected detectors, powered off both mains and a battery.

Now interconnected detectors were pretty new on the market at the time, and ones powered off both mains and a battery were rarer still. The real question is was that the best trade-off for the time? Interconnection is certainly a good thing, and mains powered smoke detectors are likely powered and function far more of the time than battery (only) powered ones.

If you get something like a Nest Protect, and put it in an existing house, and it gets connected, with less than perfect reliability, via WiFi, to other smoke detectors in the house (where no such thing existed before), is that not at least a step in the right direction? Or should be either demand that older buildings be retrofitted with interconnect wiring, or not have interconnected alarms at all?

In any event, when I figured out that the wired detectors in my house had no batteries, I simply installed an inexpensive battery operated stand-alone detector a few feet from the detector on the main floor. Which deals with most of the issue.

Start with the company going broke and its servers being turned off! Then consider technical issues.

Stunning mis-design from a very well known and well publicised high tech company, Tesla.

Although none of that should really be required for those to run as singleton smoke detectors.

Yet another case of something designed as a backup system becoming the primary system, without meeting all the requirement of the primary system. The obvious solution is to allow the car to use a Bluetooth connection to authenticate the driver's phone. OTOH, that introduces a new security issue - your phone can then always unlock the car, even if it's been stolen and the account disabled.

I can't believe (?) that a smoke detector has to contact the manufacturer's server before it can contact its *peer* smoke detector in the next room! (?)

I also don't see the need for a real 802.11 stack just to chat with another smoke detector WITHOUT RUNNING WIRES in the home.

This sounds like a case for "shoot the engineer"...

Actually, people regularly rely on assumptions that are baseless. When you quiz them ("And what if there is no cell phone coverage?") you can almost see the clutch drop out of their thought process as they then stumble to reengage it: "Huh?"

We call these colossal FAILS *bugs* (, latent).

Well, yes.

I remember a ong-running advert for a car, where every feature was marked "No", e.g. water-cooled engine: no except for central door locking: yes[1] [1]all doors can be reached from the drivers seat

On a clear night, the sky temperature in the thermal infrared can be that low. In the atmospheric windows it can be 100K, and of course in microwaves it's basically just the temperature of the CMB, ~ 2 kelvins.

Cheers

Phil Hobbs

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