(Topic at hand was just building an emergency alert system into smoke detectors rather than try to come up with some complex internet-oriented design.) On January 14, 2021 at 03:56 jra@baylink.com (Jay R. Ashworth) wrote:
Last time I looked, consumer residential smoke detectors were still running off 9V alkaline batteries, which are expected to run the device for 6 months of 1/99 duty cycle (or less, probably *way* less).
Look again, as I said in the OP most consumer smoke detectors today are sealed ten year, can't replace the battery (well, not without surgery.) I've no idea off-hand what they're using inside tho it's probably not difficult to find out, $10 and a hammer if nothing else.
An Energizer 9v is rated for 8.4VDC in the very general vicinity of 500mAh.
How does that compare to other factors like ambient temperature which also affects battery life but we mostly consider "in the noise"?
A lot. Increasing the alert count from the 1 or 2 it probably is on most smoke alarms to 2 or 3 a *week*, with LOUD analog speaker alert playback is going to change that duty cycle, probably, to something like 10/90. [ All numbers pulled out of my butt for illustration, but probably within half an order of magnitude. ]
I don't understand what you're designing but all I was suggesting was a smoke detector with a built in RF switch which upon hearing the magic signal started squawking "EMERGENCY ALERT!" or similar, perhaps with a coded word or two like "EMERGENCY TORNADO ALERT!" or perhaps a brief suggestion to consult your favorite emergency medium immediately (TV, radio, phone, religious text, etc.) Or perhaps that would be understood if it ever starts squawking "EMERGENCY ALERT!" or similar. Some of them now just start barking "EMERGENCY! EMERGENCY! FIRE! FIRE! GET OUT OF THE HOUSE" over and over. I hear them go off nearby fairly regularly so that rings in my head I'm not making it up.
Could we make the battery just a little more powerful? How much power would a bit of circuitry waiting for a "turn on! there's a new message coming in!" need?
Well, parsing for EAS on the receiver is going to make its drain non-trivial, too, I think.
But there are "increasing the battery replacement frequency" problems *and* "increasing the battery capacity and hence price, not to mention general availability" problems balancing that out.
Any way you play it, it has to be an optional model, not a general takeover of the field, I suspect, or the "well we just won't bother anymore" factor takes over.
But none of these power problems etc applies to any of the other proposed solutions? Phones etc? Or internet connections in general? Meh, I'd like to hear the thoughts of a smoke detector product engineer. My WAG is the only major objection would be that they're already neck deep in regulatory compliance and OMG this would add another layer of that, new orgs to answer to, new paperwork, etc. But so what else is new, ask marketing if it'd be worthwhile anyhow.
Cheers, -- jra -- Jay R. Ashworth Baylink jra@baylink.com Designer The Things I Think RFC 2100 Ashworth & Associates http://www.bcp38.info 2000 Land Rover DII St Petersburg FL USA BCP38: Ask For It By Name! +1 727 647 1274
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