Re: Car alarm that goes off when in a certain distance

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On Sun, 26 Feb 2006 08:03:09 GMT, Frank Olson
<Use_the_email_links@xxxxxxxxxxxxxxxxxxxxxx> wrote:

>Karl Magnus wrote:
>>
>>>>>  Hi,
>>>>> Hope someone can help with this.
>>>>> I would like to be able to set up a alarm on a car. It would only go
>>>>> off if the car got in certain distance of some point, say 100 feet.
>>>>>
>>>>> In other words if the car drove up to where I work my alarm would
>>>>> sound that the car is nearby.
>>
>>
>> I have done this. I used a ITI transmitter (long life) and a Mercury
>> switch attached to the input terminals. Dip the transmitter (once
>> programmed in to your system) in that stuff they sell to coat your tool
>> handles for protection. Then mount it on the "ledge" underneath the
>> front t bumper or somewhere else. As a call pulls up and slows
>> down/parks, the mercury will shift back and forth causing the
>> transmitter to transmit. On the ITI stuff, you can put it in group 25
>> (older panels) and it should be "non-supervised". This will cause the
>> alarm to chime anytime the car pulls up withing range.
>>
>> KM
>
>
>Excellent solution, Karl.  I didn't realize they still sold mercury
>switches (what with the environmental concerns and all).  I suppose any
>good movement detection switch would work (and automotive types would be
>weather-proof too).  While I'm thinking about this we should also warn
>the OP that you can't guarantee the range on the transmitter will always
>be optimal.  I'm not sure what to suggest about that as I've often found
>the position of the transmitter can affect the signal strength/range.

Ok thanks for some of the suggestions, I looked up ITI transmitters
and didn't see what I was looking for, I will have to dig a bit
deeper.

I really thought that there was some type of simple device out there
that had a long life battery in it that I could just slap under the
car. Then set up the reciever/dection sensor inside, and be done with
it.