What are these for?

[AlexD333]

Been meaning to ask for a while, (might get banned for too many posts) :augie

Any ideas? Doesn't seem to emit a sound :nenau

 

[geoffdown]

Been meaning to ask for a while, (might get banned for too many posts) :augie

Any ideas? Doesn't seem to emit a sound :nenau

Interior alarm.

 

[Lazy-Ferret]

Thats the ultra sonic alarm parts, that get disabled if you press the alarm switch on the dashboard.

 

[Sweety]

As Clive has said it's the alarms ultra sonic's:thumbs

 

[Blocky10]

Yep. They look better with the cover taken off and posted to me! :-D

Sent from my C1905 using Tapatalk

 

[AlexD333]

Thanks for the replies guys, I missed this post all together somehow :nenau

So what, it emits a siren inside if someone is breaking in?

 

[kitchenman]

I think it senses a change in air pressure or motion and set off the alarm
I had on in my Citroen, passing lorries when I was parked set it off, the slipstream reduced the pressure inside the car, alarm thought the door was opened, even passing cars set it off if a window was slightly open on the road side PITA:doh

 

[solarman216]

no one is a transmitter the other is a receiver all the time they communicate without interference every thing is good but broken window or other disturbance = alarm, Rick

 

[AlexD333]

no one is a transmitter the other is a receiver all the time they communicate without interference every thing is good but broken window or other disturbance = alarm, Rick

Ah there we go, thanks. And thanks kitchen :thumb2

 

[Lazy-Ferret]

They are very clever, I built one when I worked at Kent & Canterbury University, They work on the Doppler Effect, which is what you hear when a car passes. As it comes towards you, it sounds like someone has turned the Treble up, and you hear a higher frequency, then as it passes, the treble gets turned down, and the base turned up, and you hear a lower frequency, but in reality, the car made the same noise all the way along.

Basically, one side is a transmitter, which fills the car with ultra sonic sound waves, and the other side listens out for the reflected waves coming back at the same frequency. If something in the car moves, the reflected waves will either increase or decrease in frequency, depending on which way the item is moving in relation to the transmitter. If this increase or decrease falls within specific parameters, it sets the alarm off.

The great thing is, air movement should not normally set it off, but if the air movement blows something hanging in the car, such as an air freshener hanging from the rear view mirror, or a passing lorry shakes the car and makes something move, then it will be set of erroneously. If a window is open, then the sound will not be reflected back until it hits something outside the car.

 

[John B]

It's nothing to do with the clutch damper pipe :lol :lol

 

[AlexD333]

It's nothing to do with the clutch damper pipe :lol :lol

Hey who knows, nissan are nuts, it could well be related :naughty