Re: Help with 7 Circuit Project?

["Robert L Bass" <robertlbass@xxxxxxxxxxx>]

> Of course, human activity is what alarms
> are looking for in the first place, so
> whenever you start limiting the system,
> you're increasing the chances that a true
> alarm WON'T be reported.

In this case it's the activity of humans who live at the protected premises
that causes most problems.  I try to set systems up so that the homeowner is
unlikely to accidentally trip an alarm.  That usually means deactivating
("shunting") interior motion detectors and glass break detectors when the
family is home until they retire for the night.

>> The IntelliSense (now part of Honeywell)
>> detectors I use only occasionally false if
>> the storm is intense and directly overhead.
>> With a panel like the ELK M1Gold there's
>> a way you could configure the glass breaks
>> to be "lightning proof".  When thunder
>> triggers glass breaks it usually trips several
>> of them.
>
> Usually, but not always in my experience.

If only one triggers the alarm signal is sent.  Only if multiple detectors
trip in rapid sequence do you want to ignore glass breaks.

> The trick here is to figure out what the
> weather conditions are independently
> of the intrusion sensors and then bias
> their reports accordingly.  Now I'm not
> sure this means a using a lightning
> detector of some sort, or monitoring the
> NWS via the net (or better yet, by radio)
> or what, but clearly an "ultra smart"
> alarm system would take the weather
> into account.

To effectively decide when to ignore a condition based on weather you would
need a panel that simply does not yet exist.  It's good to dream of ways to
improve things in the future, but we have to deal with the present, using
technology that is available today.

> We have a large apartment house nearby
> with a large, outside parking lot.  It's
> bordered by open parkland and is the
> only structure above 10 stories for a
> radius of 10 miles.  When there's a severe
> storm, a building hit will set off anywhere
> from 1 to 5 different car alarms...

I don't really deal with car alarms.  Most are useless junk.

>> Have the glass break zones start a timer.
>> If any glass break zone is tripped wait 10
>> seconds before triggering an alarm.  If a
>> second glass break activates within that
>> time frame, take no action.
>
> That's certainly one approach.  It's based on
> a burglar only smashing one window, which
> is probably a pretty good assumption.

Not one window -- one window within range of a single detector.  Glass
breaks are not designed to protect multiple rooms.  Typically, there is one
detector per room and each is (or really ought to be) on a separate zone
(sensing circuit).  I've yet to see a situation where the thief broke
windows in separate rooms within a 10-second interval.

> As a Floridian, you must be aware of
> what happened after Andrew.  There
> were a *lot* of burglars smashing a
> *lot* of windows!

TTBOMK, noone was smashing lots of windows in different rooms of a single
home in rapid succession.  However, after Andrew hit there were large
numbers of homes without power for weeks.  None of their security systems
were working.  Also, phone lines were down so many alarms weren't able to
call the central station.

You can't really build a commercially successful alarm or automation control
that will handle earthquakes, hurricanes, forest fires or riots.  It's also
highly unlikely that we'll see an affordable HA system that makes processing
decisions based on lightning proximity any time soon.  For now, the best we
can do is use the tools that are currently available, mix in a bit of
ingenuity and experience and come up with something that minimizes problems
while affording a reasonable degree of comfort and security.

--

Regards,
Robert L Bass

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