DIY car alarm ??s [update]

[terminaldegree]

Howdy folks,

Any words of advice before I jump into a project like this? I have installed multiple stereos and amps before, but never one of these.

-my car has manual locks/windows, and the trunk release button under the dash
-I was thinking of a "modular" approach: shock sensor first, then maybe starter kill/power locks/trunk release later on as I have time/money to install them
-I am intrigued by the radar-type perimeter sensors. Any input on those? Where to mount it? Do they work? I was thinking of putting one on my sub box on the back deck-- good line of sight to the rest of the windows.

Of course, suggestions on brands [please nothing expensive] are welcome.

Thanks,
Owen

[ September 12, 2004, 11:27 PM: Message edited by: terminaldegree ]

[nda0602v6]

The 'starter kill' feature isn't something you'll want to install down the road. Most (not all) alarm systems already come with a separate Relay that's used for the starter kill feature. (Even if a Relay isn't included, they only cost a couple bucks). It's just easier to wire up the starter kill feature while you're installing the alarm itself.

Another thing I would suggest doing now instead of waiting down the road would be to wire up the power trunk release as well. All that's needed is another inexpensive Relay. You can add power door lock actuators later on.

If you feel comfortable working with automotive wiring and you can install amps & stereos, you can install alarms. I just strongly advise that you take your time and make 100% sure you know which factory wires you are tapping into. This sites Modification Encyclopedia gives detailed information on which wires you'll need to use when installing an alarm. Please don't hesitate to post questions while installing the alarm, there are many people here who will help you.

Also, do you have some sort of price range you want to stay in? Here's an inexpensive alarm made by Prestige. just an idea, they get more expensive.

[terminaldegree]

Thanks nda,

I can certainly afford the one you linked. I was thinking about keeping the whole thing under $130 [including everything needed to install] if I could.

I appreciate your advice and offer of help. Couple more ???s for you then--

-Are relays universal, i.e. not brand specific?
-Are all brands in the lower price range basically the same?
-Any opinion on the perimeter alarm option?

The only reason I come back to the last one is because my amp and sub are rather exposed through the back window, and I was interested in providing a "deterrent" to those who put their nose up against the window to take a peek.

-Owen

[nda0602v6]

Any 12volt (SPDT) 30/40 amp automotive Relay can be used with any car alarm, regardless of who makes the alarm. If you need to get some extra Relays, I'd also recommend getting the 'sockets' for them as well.

12volt 30amp Relay - Bosch brand
12volt 30 amp Relay - Generic brand
Relay Socket

I can't really say if "all brands" in the lower price range are all the same or not. There's definitely some junk out there. I'd stay away from those alarms that have the brain built into the siren or only have very minimum wiring, i.e. those "two wire hook-up" alarms where all that's needed is a positive and ground hook up. lol no good there. Names like Prestige and Crimestopper have been around for quite some time and offer decent low price security systems. Maybe someone else here can suggest a specific name brand for you.

Things like shock sensors and 'perimeter' sensers can be very effective IF they are calibrated correctly. You obviously don't want the sensitivity set so high that if someone simply walked by (like in a parket lot) the alarm would sound off. Again, how well an alarm works (low cost or even expensive alarms) depends on how well they've been installed and calibrated.


Also...here's an inexpensive power door lock actuator kit, it even comes with the Relays
Door lock kit

Or you can piece it together.
Door Lock Actuator
Then just add two Relays.

[ August 31, 2004, 11:52 AM: Message edited by: nda0602v6 ]

[terminaldegree]

Alright. I'm ready to go out and buy stuff to do this.
Why? Looks like someone unsuccessfully tried to get into my car using a hangar last night, scratching up my driver's side tint a little. [thank goodness for the extended warranty on the tint!]

I have a final couple of questions for the board-

Does a "voltage sensing" alarm go off if you open the door before it is disarmed [when the dome light is triggered]? That would have helped if they actually gained entry to the car.

I'm having a hard time delineating between the various models and their features. The shock sensor is fine, but I want something more that would have helped if someone got into the car using a "slim jim" or something like that.

I'm trying to stay around $100 or less, and I will install it myself. All other relevant info about the car is posted above.

THANKS FOR ANY HELP. THIS EPISODE SPOOKED ME, AND I REALLY WANT TO GET GOING ON THIS PROJECT.

[nda0602v6]

Sorry to hear about what happened.

A 'voltage sensing' alarm means exactly what it says. Once armed, if the alarm senses a spike (or sudden change) in the vehicles voltage, it will trigger off the alarm. Something like a dome light turning on would trigger the alarm. You also have the option of 'hard wiring' an alarm to the pin switches to detect if the hatch or doors were opened. I personally don't like relying on just voltage sensing alone to detect if something was opened. Some alarms give you the option between voltage sensing or hard wiring. I'd go with hardwiring if I were you. (only requires hooking up a couple more wires).

Yeah a shock sensor isn't really going to do you any good if someone is using slimjims or coat hangers. You need something like one of those 'radar' type sensors, which would detect movement in and outside the car. If you adjust them right, the alarm will give out a 'warning' chirp from the siren if someone gets too close to the car (close meaning if someone puts there face right up to the glass trying to look in). The alarm will fully sound if the sensor senses something inside the car (like a coat hanger or someone's hand moving around).

Example of an inexpensive radar motion sensor...
radar sensor

hope this info helps

[terminaldegree]

Thanks again Nick,

I went ahead and bought a Crimestopper alarm and the radar sensor through that particular ebay vendor. I'll let everyone know how it goes, just in case anyone else is curious about doing this yourselves.

[nikon]

I got a proximity sensor on my car...works exactly like its supposed too...this isnt a good thing all the time...in order for it to watch over my stereo in the trunk I have to turn it up so high that if you walk within 2-3 feet of my car it will give a warning chirp..if you stand there for about 3-4 seconds it will sound off...and for the rear you have to almost be touching the car to get it to chirp...shock sensors I dont really like...they work but if you have them set to sensitive loud exhaust will set it off...too low and someone could smash your window and your alarm would never go off...its all about placement....I but my proximity sensor in my glovebox taped to the top of it...works great there...the shock sensor is mounted to the steering column, you'll find most people put them there...if you are able to find an alarm that gives you the option of a "full" arm of "half" arm so to speak...such as only arming your shock sensor and voltage sensor that would be the way to go...because you dont always want that prox sensor...