Printer Friendly Forum Posts - How do I install a 2nd siren?

I just installed a COMMANDO alarm in my car. I mounted the siren under the dash as to give any thief a massive headache if he tried to mess with it. But now I can barely hear the siren from outside the car :(

Does anyone know of a way I can hook up a second siren under the hood? If I hook it up in series, then cutting any wire from the siren under the hood will kill both sirens. But if I hook it up in parralel, I'm afraid the amp draw might be more than the alarm system can handle.

I have no experience with these things. Any advice would be much appriciated.

Hey Reepicheep,

The sirens should always be wired in parallel. If unsure about amp draw use a relay to drive the sirens giving you up to 40 amps. posted_image

-------------
Prepare your future. It wasn't the lack of stones that killed the stone age.

Thanks Big Dog. I'll try hooking them up parrallel and if a fuse blows, I'll buy a relay. Cross your fingers for me.

I did speak with Tech support from Commando Alarm earlier. He mentioned something about placing a 1 amp diode facing the first siren. I'm assuming he ment that I should hook them up in series, otherwise it just doesn't make sense. He was a bit grumpy so I decided not to ask for more details.

Reep

Thanks Big Dog. I'll try hooking them up parrallel and if a fuse blows, I'll buy a relay. Cross your fingers for me.

I did speak with Tech support from Commando Alarm earlier. He mentioned something about placing a 1 amp diode facing the first siren. I'm assuming he ment that I should hook them up in series, otherwise it just doesn't make sense. He seemed a bit grumpy so I decided not to ask for more details.

Reep

Hey Reep,

Thank God for tech support huh? posted_image

When he said diode he probably meant to diode isole them so that one doesn't feed back into another this doesn't make any sense at all....

Assuming your siren is driven with a neg trigger connect the siren output from your alarm brain to pin 85 of a relay, 86 and 30 goes to a positive thru a fuse and 87 splits two ways to the sirens. Then its ASTA LA VISTA, BABY!

-------------
Prepare your future. It wasn't the lack of stones that killed the stone age.

STOP THE MADNESS!!!

I just did a quick search through the archives, and I now have 3 conflicting methods of hooking up a second alarm!!!

Big Dog wrote: Assuming your siren is driven with a pos trigger connect the siren output from your alarm brain to pin 85 of a relay, 86 and 30 goes to a positive thru a fuse and 87 splits two ways to the sirens.

the12volt on March 21 wrote: connect a lead to your alarm's siren output. if your alarm's siren output is (+) connect it to termianl #85 and connect #86 to ground. Connect terminal #87 to constant 12V+ (fused) and connect terminal #30 to the positive leads of the other sirens you are adding.

hot_shot_guy123 on March 21wrote: PIN 86 = trigger wire from siren output from brain (pos or neg depending on your alarm) PIN 85 = Ground PIN 87 = Constant 12V (make sure to fuse this wire) PIN 30 = Hook up sirens to this pin

All three are correct. Terminals 85 and 86 are for the coil. It doesn't matter which one gets positive so long as the other sees negative when you wish to energize the coil. Terminals 30 and 87 are normally open, they become closed when the coil is energized, so long as one has 12V+ the other can be connected to the positive lead of the sirens.

-------------
~wirewise~ Verify all wiring with your meter before making any connections!

Hey Reep,

I goofed ( doh! )

Should of said Assuming your siren is driven with a neg trigger connect ......bla,bla,bla posted_image

Big Dog have Big Tail between Big Legs! posted_image

The greatest sign of humility is to fes-up to your mistakes then post it for all to point and laugh posted_image

O.K. guys ! That's enough ! Stop rolling on the floor ! Just wait....... posted_image

-------------
Prepare your future. It wasn't the lack of stones that killed the stone age.

"Bad Doggy! Bad!"

Reepicheep have positive alarm output.

Bah! I read Big Dog's initial description too quickly, since he clarified using a negative output from alarm, his is now correct, but since you have a positive output from your alarm, use the12volt's description. It will work correctly with your alarm.

-------------
~wirewise~ Verify all wiring with your meter before making any connections!

Ahhhh, nothing like the process of peer review to get to the bottom of things

posted_image

Well, I'm going to try just hooking it up parallel first without any relays,,,,,, unless,,, anyone has any more afterthoughts posted_image

Reep

Out of habit, I'd play it safe and use the relay...it's not like they cost an arm and a leg.

-------------
~wirewise~ Verify all wiring with your meter before making any connections!

I'll take your wise advise "Wirewise".

But here is one more idea. How about I just splice into my horn instead. It might not sound as pretty, but who cares. The only problem is if I don't use a relay, my alrm may sound off every time I honk my horn,,,,unless,,,,,I use a diode.

Hmmmm, or maybe I should just leave the wiring to the profesionals posted_image

Reep

Reep, why not just add the relay and mount the siren inside the vehicle to do what you wanted to do in the first place? Connecting it with the horn is possible, but why would you want to do that?

-------------
~wirewise~ Verify all wiring with your meter before making any connections!

Well the whole idea is just to make some noise outside of the car. It would be easier to use the horn (no mounting, and the wiring is already in place) and cheaper: I would have to purchase the siren and relay online ($20.00 with shipping/handling).

Reep

you should have a siren outside to attract attention. I have 5 sirens in total on my car now. I have 1 hidden in the front of the car and 1 hidden towards the rear bumper. The other three sirens are in my vents, they are mini piezo sirens (pain generators). I would definetly use a relay. If you wire up 2 normal size sirens in parallel you risk blowing the siren output of your alarm. There's no fuse there unless you add one. With a relay you could probably add 20 sirens with no problem. Be safe and add a relay.

You are only as good as your worst install!!

5 sirens in your car sounds like overkill. Do they all have seperate power supplies? Because, all a thief has to do is pop the hood and yank the battery cable to dissable all the sirens you put in. And if it's too loud, a car thief can actually sue you for damaging his eardrums - this happened in California.

Well, I tried to hook my horn up along with my interior siren. It didn't work. The horn made a little whimpering noise, and the siren sounded at half volume. So I guess I'll go with the relay and siren.

Also, I'm relocating my hood release to prevent the situation I first mentioned. Just call me parinoid. (and I have a cheap car, too :)

Reepicheep

I do have a seperate battery for my alarm, I figured that they would snip the cable to try to shut it off. I have a dry cell, deep cycle batt for my alarm. It is small so I hid it between the panels. This battery has enough juice to start a camaro with a 350 in it. It holds the charge very well. Your hood release, are you talking about the one from inside or the one you have to move after you pop it from inside? If you look from the front of the car can you see the cable(thru the grill) that goes to the hood lock? I'd hide that too cause if you yank on that hard enough your hood will open.

hot shot
does having the mini-sirens in the vents take away from your A/C or heat? i.e., hardly any air blowing? i was thinking about doing the same since i have my dash taken apart but i don't want to take away from the a/c( i can barely feel it as it is). and would you need a relay to add just one piezo? how about the battery powered back-up siren from DEI?
only in Cali can someone who broke into YOUR car sue you for damaging his or her hearing.

Hi Bud

It all depends how you mount the piezo sirens. My piezo sirens come through the internal ducts. I had to cut a rectangular hole the size of the piezo so that it just barely enters the vent ducts on the inside. I then sealed the area around the piezo. It keeps the airflow flowing at its max. If your adding 1 piezo then you don't need a relay. The piezo uses about 1/ 3 the power of a normal siren. About the DEI siren, are you thinking about having that one inside? If you add that one you will have to have a relay. The siren output is made really for only one (normal size) siren. It's good to add a relay cause if down the road you want to add more sirens you can. If you need any help with any of the siren set-up's just ask, I'll try to get back to you as soon as possible.

hot_shot_guy123

hot shot
i want to add the piezo in the vents like you did and a battery powered siren under the hood. i already found a place to put it, it requires some removing of parts but this should make it harder for a thief to get at. i'm thinking about using metal conduit to protect the wire from being cut. about the battery who makes it and how small is it? the size of a VHS cassette? a pack of cards?

Hi bud

The battery is a little bit bigger than a video cassette and the brand is "Odyssey" I came across it at a local starter and alternator shop.

Hey Hotshot - I just posted a question yesterday with a PS about piezio "pain generators," and now, here's someone who has used them! Where did you find them? I'm adding a horn honk and something like a piezio in my cab. I want as much attention on my truck as possible when it goes off!

-------------
/NyxBass

Hi NyxBass - I purchased the piezo's from a shop in Canada called The Speed Of Sound. If you go to any stereo shop that does alarms, they should be able to get you some. There are a few different brands of piezos on the market. Make sure you get the ones made by DEI. You will notice that if you install 1 piezo inside your truck that it is barable. I had one in mine then I decided to add 2 more. Now you feel it big time in your ear. They have a wierd tone that makes you cringe like when someone scratches a chalk board. You can check online here https://www.autopreservers.com/security/acc/513t.htm they sell them. Any more questions about them jusk ask posted_image

Have you thought about getting an air horn for your alarm instead of using your factory horn? They are louder than any siren.

hot_shot_guy123

I've thought about an air horn, the problem being that 1) they are big, and take lotsa power. Meaning, a backup battery's not going to last too long with it goign off. Also, most air horns work off of a tank, and when that tank's pressure get low, they kinda just sound... "deflated"...as you can imagine. Not very scary or impressive, or even attention getting. I have thought about an electronic air horn, but I'm not to the point of needing that much security or spending that much $. Thanks for the piezio info though!

-------------
/NyxBass

two piezos it is then, i wouldn't need a relay would I since they only use about 1/3 the power of a regular siren.

Well since your using more than one piezo, you might get away without using a relay. I didn't use a relay at first when I had 1 external siren and 1 piezo. When I got my other piezo's and my other external siren, that's when I wired up a relay. I tried to keep away from using a relay at first cause I was afraid to hook up one wrong, but after asking questions on here, I put one in. Easier to do then I first thought and it gives you piece of mind knowing that you won't blow your siren output due to excessive current draw. Just to be on the safe side, I'd put one in. If you want I can try to send you a diagram of how my sirens are hooked up. Just leave your e-mail

hot_shot_guy123