QuestionHi-
Thanks for your ever so quick response. The reason I am asking these weird questions is
that I am doing some accuracy research for a film in which car alarms play a prominent part.
I am still a little unclear about how the alarms work, but perhaps it would be easier to ask
how would you describe the mechanism, specifically how it works, to a layman? Right now it
is described thus: "most of them operate on a tong-and-ring like the tilt mechanism of a
pinball machine.. they can be set off by someone breaking into a vehicle, or bumping into it,
or for that matter by other alarms..." Does the description of how it works seem accurate, or
is that at least one way that it can work? How would you word it?
Also, when you say that the good ones are mounted up in the underdash where the wiring is
located, do you mean the wiring to the power source or to the ignition, electrical system,
etc. I am sorry these questions are so remedial but I know less to nothing about cars.
Can't a car thief simply break a window, pop the hood and sever the connection cable from
the alarm to the battery without disengaging the battery from the car? In my mind this
seems so simple that I know it must not be true, but that is the scenario proposed in this
film, so I am asking the obvious. Thanks again in advance for your advice!
Best,
Nina
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Followup To
Question -
1. Are there any car alarms that run solely on their own power source, or do they all draw
power first from the car battery and then sometimes from a backup battery? I am looking
for a model that only operates independently of the car's battery.
2. How does a car alarm work? Are they triggered by a tilt of the car, like the tilt mechanism
of a pinball machine? Or tong and ring? Can you explain the mechanics?
3. Where are car alarms physically installed in the car in relation to the engine? Near the
manifold? Or where?
4. Can you shut them off merely by disconnecting the battery cable, if that is their only
power source?
Thanks.
Answer -
Ok, one by one....
1. Are there any car alarms that run solely on their own power source, or do they all draw
power first from the car battery and then sometimes from a backup battery? I am looking for
a model that only operates independently of the car's battery.
Car alarms do not come with a self contained power
source. Some can be set up with it's own external supply
for different applications (see my site at www.securetrailer.com) and I can suggest how
this can be done for a car/truck, but I don't
share that with non customers for security reasons.
2. How does a car alarm work? Are they triggered by a tilt of the car, like the tilt mechanism
of a pinball machine? Or tong and ring? Can you explain the mechanics?
Car alarms are set up in several ways. Some geared
to detect dome light on or off. Some detect battery
drain on any given wire and will set off that way,
some have external or internal shock/impact,
motion, sound/glassbreak and mercury(tilt) switches
or modules. There is a lot to choose from.
You can also add video cameras that detect movement
and will turn on as soon as someone enters the car.
But th short answer is the alarm is a device
that detects changes in it's monitoring capabilities,
and then reports it through light flashing, siren,
horn honking, or 2 way paging.
3. Where are car alarms physically installed in the car in relation to the engine? Near the
manifold? Or where?
Most (good ones) are installed high up in the
underdash area, where most of the wiring required
are located. Some "selfcontained" system (cheapo)
would be mounted as the sire is under the hood in
a location that allows for loud sound and system
saftey like a fender well. You want a good one
for safet. The cheapos are only noise generators
and are not much of a deterent.
4. Can you shut them off merely by disconnecting the battery cable, if that is their only
power source?
Unfortunately, yes. Without a backup supply,
when you remove the battery it will be dead.
But so will the car. Still can't steal it
and if starter kill is part pf this mix,
then it's a catch 22 for the thief. He would
then need to remove the alarm wiring, and then
re attatch the car's wiring back to "original" pre
alarm condition before he could steal it.
Bottom line, car alarms are meant to be deterents.
When doing yours, protect it accordingly.
Thanks.
You are welcome,
be well.
ALARMTEK
visit www.MRINSTALL.com
and www.12VOLTPLANET.com
for some more idea and explainations.
AnswerThe "hollywood" solution, is a bit simplistic,
but remember, severing the battery will simply
kill everything in the car, alarm included.
That does not help. Can steal it without power.
The sensor device that is described is
essentially accurate.
A standard 2 stage shock/impact sensor is
what is found in most alarms, and depends
on vibration.
A "tilt" sensor is a mercury switch, (older alarm)
and is like a carpenters level.
If the car is hooked by a tow truck and is
angled at 20% either way, would set off the alarm.
The things not apparent here, are the extras.
The starter disable relay, the remote paging etc...
All of these veriables make the "film" inaccurate
to a point. The gray areas are not addressed here.
As I said, it's a quick hollywood fantasy.
If you look at "gone in 60 seconds", they take
many artistic licences to tell the story. These
"super smart" electronic devices they used are
also a bit of sci fi. If it was that easy, then
I might be on the other side of this business!
Of course there are easy cars to steal and nearly impossible to steal cars too, but in actuallity,
when a thief looks to steal a vehicle, they look
for vehicles that can be stolen, or moreover,
ones that have no apparent alarm in it.
Alarms make the theft too dangerous in most cases
(unknown veriables here are your proximity and
reaction time) making it unwise to steal.
The normal thief will usually move on to the next car.
As you can see, too many unknown veriables to
make the car a good target.
Lastly, the reason we do car alarms up under the dash
area is to make it harder to take the vehicle.
If a backup battery is installed (how would
the would be thief know that by the way?)
then you would need to put it up on a truck
and tow it out.
Also keep in mind that before they car
cut the battery power, the siren is sounding,
and if installed, the pager has already notified
you that it was breeched. This let's you
jump up and get involved immediately.
No it's a movie. In a "perfect" world and all that.
Best advice here is yes, question the validity
of the film to a point, but to allow the maker
the flexability to "fudge" a bit on the truth.
He is using his artistic licence to tell the
story, but not revealing the total picture about
car theft.
I hope this helped.
ALARMTEK
CARALARMZ.COM
Make fo a more enjoyable day at the movies.
