From: jreiser@scott.skidmore.edu (Jason Reiser... Asleep)
Subject: Re: CAR ALARMS!
Organization: Skidmore College, Saratoga Springs NY
Date: Sat, 21 Nov 1992 11:33:01 GMT

v523d85n@ubvmsb.cc.buffalo.edu (Robert C Maggio) writes:
>  
> a quick question and answer and info session:
> 
> since we are on the topic, exactly how should one set the alarm sensitivity?
> mr Runkle just said that slapping the bumper  wasnt a good enough test.
> i know that my car has to be smacked pretty hard in order to set off the alarm.
> 
> oh yeah, hey, mr Runkle, did you test that glass breakage sensor by shattering
> one of your back windows?  just kidding.  i do wonder how all these people
> set their shock sensor sensitivities though.  i used the smack the bumper method
> and i mean a good smack.  i also parked it by an air force runway with jets
> flying with full afterburners and in a place where trucks go by(in a small town 
> while i was on vacation-a safe place)

Testing shock sensors can be done in a number of ways.  I wouldn't
highly recommend slapping or otherwise abusing the body panels as
damage may result.  Instead, the best methods I've found are to hit
the center of the windshield with either the ball of the hand (where
hand meets wrist) or with a closed fist.  Other useful methods are
kicking the tires with the ball of the foot (NOT the toe... that's
painful).  And of course, one could result to such real world testing
as suggested above (aircraft, Harleys, trucks, etc.)

Testing glass breakage sensors is easy IMHO.  Simply adjust the sensor
until it is just barely able to sense the following...  Go around the
car and wrap on the glass with an automobile key.  (Of course, other
keys will do, but I'd suggest a fairly smooth one, so as not to
scratch anything or cut yourself in the process.)  You will basically
stab at the glass with the key and turn the sensor to it's least
sensitive triggered response.  Here to you could try the real world
testing... Harley's will sometimes vibrate the car just enough to set
these off, even if it seems properly adjusted... and a slightly
insensitive one is OK... a thief will hit the window much harder to
break it, and will shatter the glass... leading to a noisier and more
easily detected break in.

> my personal suggestions:
> 
> two shock sensors, one sensor for both front and back is NOT enough.  no
>  	sensor can cover the whole car alone

I strongly disagree with this statement.  If one sensor will not cover
the entire vehicle properly, and with very similar sensitivities... it
is either poorly installed or of inferior quality.  Note that some
vehicles may present an exception to this... such as overly large
ones.  

> set them independently, i.e. smack both bumpers soundly until the alarm no
> 	longer triggers.

This holds true for any group of sensors... always disconnect the
other sensors when working on setting another.  Otherwise, you may
have more than one triggering from your attack on the vehicle.
 
> a glass breakage sensor is another must

I don't know that it is a must.  These are great to stop breakins that
may foil a shock sensor (such as bending a window until it breaks...
though I've never actually seen it done and still think it may trip
the shock sensor.)  Such devices are more useful in fair weather
states.  In the north east where hail, sleet, snow, cold, etc. are the
norm in the winter, I will often turn my glass breakage sensor off.
Hail is the sensor's worst enemy, and ice on the window can be almost
as bad (compression and relaxation of the glass... or cracking ice)


I think that all the recent talk on the subject of alarms... from all
different standpoints really proves the necessity of an alarm group.
There is so much to discuss... so lets get to it already.

Looking forward to an official rec.autos.security call for votes,

				- Jason




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\ Jason A. Reiser  \ Send E-Mail to jreiser@scott.skidmore.edu \
 \ Skidmore College \ Saratoga Springs, NY 12866 \ 518-581-6580 \  
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Newsgroups: rec.audio.car