Alarm went off at 2.00am this morning. (1 Viewer)

[GWAYGWAY]

The alarm on my van went off and when I got out there noting was seen to be tampered or open, I reset it and went back to bed. This afternoon I checked and found that if I pulled hard at the front nearside bonnet flap ( a Hymer A class) where it is against the headlight The microswitch set the alarm off. Why should anyone do that? They can't get anything in there or is the alarm just a bit sensitive. I am just a bit paranoid as it is the only new thing I have ever had and the dearest. The only other thing is my neighbour has a long drive over the fence and his Mercedes car has a very deep exhaust note not noisy but very low frequency, can that set the ultrasound sensors in the hab area off?

 

[sdc77]

I'm pretty sure a spider set our alarm off .. Oh yeah and the mouse deterrent thingy sets it off too

 

[Dazzlin]

[QUOTE="GWAYGWAY, post: 1960324, member: ]This afternoon I checked and found that if I pulled hard at the front nearside bonnet flap [/QUOTE]

How many flaps did you need to pull to set her off?

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[wigster]

Wouldn't have thought exhaust note would set it off .

 

[DuxDeluxe]

How many flaps did you need to pull to set her off?

Here is your coat........there is the door !

 

[MR. FUSION]

The alarm on my van went off and when I got out there noting was seen to be tampered or open, I reset it and went back to bed. This afternoon I checked and found that if I pulled hard at the front nearside bonnet flap ( a Hymer A class) where it is against the headlight The microswitch set the alarm off. Why should anyone do that? They can't get anything in there or is the alarm just a bit sensitive. I am just a bit paranoid as it is the only new thing I have ever had and the dearest. The only other thing is my neighbour has a long drive over the fence and his Mercedes car has a very deep exhaust note not noisy but very low frequency, can that set the ultrasound sensors in the hab area off?

Used to be a Standard crim trick, keep setting off the alarm until the owner deactivates it......then nick the vehicle!! Or maybe break in ?

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[Minxy]

Reminds me of a former work colleague who had problems with her house alarm - she'd set it for the downstairs when going up to bed and it kept going off every now and then overnight ... they eventually found out it was a massive spider that kept swinging in front of the hall sensor!

She didn't know whether to be happy that they'd found the reason for it going off, or scared to death at the size of the spider!

 

[DuxDeluxe]

Reminds me of a former work colleague who had problems with her house alarm - she'd set it for the downstairs when going up to bed and it kept going off every now and then overnight ... they eventually found out it was a massive spider that kept swinging in front of the hall sensor!

She didn't know whether to be happy that they'd found the reason for it going off, or scared to death at the size of the spider!

One of our false alarms a few years ago was a spider actually in the unit. How it got there, nobody knows..........

The only issue we had with our Strikeback alarm was a "dry joint" with the bike loop. Got a waterproof automotive connector and no issues since then

 

[tonyidle]

I can confirm that a passing radio amateur, chatting with his friends, will set off many house and car alarms.

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[pyro]

Frequently

 

[wigster]

A phrase ive never heard , a passing radio amateur . You live and learn

 

[icantremember]

I can confirm that a passing radio amateur, chatting with his friends, will set off many house and car alarms.

.......so can police car radios!

We had an alarm system on our business premises which called us when activated. On a couple of occasions I arrived in the scarey wee dark hours only to find cop cars already in attendance only to find they had been parked up close by having a nap break and used their radios.

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[Robert Clark]

How do you know it was the bonnet sensor that set the alarm off?

 

[Minxy]

How do you know it was the bonnet sensor that set the alarm off?

Obviously doesn't like its front being fondled ...

 

[Lenny HB]

Alarms can be a bit techy at times, if you think it is the bonnet switch just adjust it they are mounted with a long thread you can loosen off the locknut and wind it out a bit to make better contact then hopefully it won't go off again.
We have had our alarm go off on occasions, leaving a rooflight open in windy conditions trips the internal sensors & leaving the heating on does it, I must remember to turn off internal sensors when leaving roof lights open or heating on.

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[hilldweller]

very deep exhaust note not noisy but very low frequency, can that set the ultrasound sensors in the hab area off?

We were at the Southport Air-show and when the jets came past they were greeted by a whole load of alarms in the car park going off. So yes, it is possible.

One reason for ultrasonics being replaced by PIR in building alarms, they can be triggered by non attack events.

 

[Wagoneer]

The engine bay is a very aggressive environment for an alarm bonnet switch. If the OP has a plunger type switch then take it off and give it a good clean to get rid of any oily residue or condensation that could cause a short circuit.

My Hymer had a reed switch (contained in a white plastic elongated box thingy). My alarm kept going off at odd times. I found that the terminals had corroded where the 2 wires connect. These were cleaned and solved the problem. The reed switches can become a little temperamental over time but you can easily test them to check if they are opening and closing properly (bench test using a multimeter).

If you are replacing a reed switch just be aware that there are two types - NO (normally open) and NC (normally closed). The NO one is the more common but mine was the NC variety.

 

[Clarky]

We were at the Southport Air-show and when the jets came past they were greeted by a whole load of alarms in the car park going off. So yes, it is possible.

One reason for ultrasonics being replaced by PIR in building alarms, they can be triggered by non attack events.

Our Vulcan always set off loads of car alarms, much to our amusement.
A couple of years ago at Shoreham it managed to crack the windscreen of one car. Fortunately the owner was a Vulcan fan and he was dead chuffed when he came over to tell us.

Richard.

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