help with my siren wires

[speed__demond]

ok i was thinking of getting a different horn as a second to the one i have but, i do have an old alarm set in the shed and it has a siren with it i know the black is ground and the red is 12v but how do i connect it to a switch with the last wire i think it activates when the last wire touches ground also but im not sure and havent got time to mess around with it yet

can anyone confirm if im right so when i do get to it i know what im doing

 

[Benboy]

Fitting siren to anything other than Emergency Veihicle is illegal (for on-road use).

 

[ImAHoon!]

it probably has a back up battery

 

[speed__demond]

its not illegal because its from a car alarm not a police or ambo siren if you had of took time to read it. i just wanna do it at work when people walk past so they panic and think they set my alarm off lol

 

[kopper69]

Hey speed__demond,

Can you just explain a little more about how you want to control the horn? So the horn will go off when the alarm goes off, but only when a switch is on (so that you can control when its on or off?) If you have another circuit controlling it (as in an alarm) you would use a relay. Is this what you want to do?

 

[speed__demond]

no i already have an alarm on the car, this is a spare battery backup one from another set but i only want the siren not the whole alarm installed. i want to activate it when im in the car so people think the alarm went off lol

it has 4 wires the diagram says one to ground one to 12v one doesnt do anything i assume its for a control to add on or somthing and the last wire which is the one i wanna know goes to the alarm and central locking thing which controls it and sets it off but i wanna set it off by a button how can i do this

 

[vlv8vic]

ground the one that says ground. then hit the other ones against the positive until it makes the siren ah i mean 'alarm' operate. Once you know which one makes it buzz put a switch on that wire.

I don't understand why you have the time/need/strange urge to 'trick' people into thinking your car has an alarm when it already has an alarm but that is your personal fantasy i guess, though i do suggest that you put a relay in that disables it when you are driving you aren't tempted to be a dick and give it a burst while you are driving.

 

[speed__demond]

lol just a bit of fun because its there doing nothing anyway

 

[alien]

OK, the 4 wires are like this:

Black will be ground
Red will be constant 12v

Then from memory the other two should be green and purple.

One is for the bonnet open switch so if the bonnet opens it sets the alarm off, the other is for the siren trigger. The trigger must recieve a positive signal (not sure how many volts, depends).

 

[speed__demond]

ok so the trigger connects to 12v with a switch inbetween?