Looking for ideas for a cheap DIY car alarm
 

Dont want or need a real car alarm

Just something something simple that makes noise when they open the door
(and/or move something)


I was thinking about a personal protection siren rigged to the door
so when they open the door past 6 inches it would go off
(they wouldnt be looking for the string at night + I could reach in and disarm it)
although id have to sprint to the parking lot as the thing is LOUD


but Im curious to hear your boobytrap ideas


http://www.anvstore.com/media/catalo.../image(82).jpg

...how bout a relay, a switch and some wiring for being cheap...

tap into the interior lighting somewhere, run a wire out to somewhere on the exterior you could hide a switch to enable/disable, edge of the hood or under the front bumper or something. then from that switch to a relay, from the relay to the existing car horn.

interior lights come on = car horn

i was thinking something external or low voltage

(since I frequently unhook the battery as a deterrant)

car alarm decals on all windows near door handles

if only decals made noise when you opened a door

An air horn rigged to activate seconds after a smaller alarm which is activated as soon as a door is opened without disabling it first.

I think I found it

Motion Alarm

now to find a cheap one

(and when I say cheap, I mean free)

http://www.comparestoreprices.co.uk/...alarm-plus.jpg

Gun, string.

Mount gun on dash, pointing at driver's window. Attach string to trigger, other end to door.

Make sure gun is loaded, and string is just long enough that you can't get into the car, but you can open the door about 5 inches without it going off, so you can disarm it if you know it's there.

Frankly, I believe that car alarms are like door locks. They keep honest people honest.

I think Ill stick with the motion alarm

LOL, Well, I can't say I blame you.

When I park in a seedy neighborhood, I toss my #15 fuse (ignition coil) in the glove box. Go to crank the engine, and the engine will turn but will not fire. Car makes noise, doesn't go anywhere, people look, crook gets nervous and walks away. Or he steals my $10 stereo and $5 in coins out of the ashtray.

Car alarms are a nuisance.

yah, homemade deterrents are usually effective, random crook doesn't usually have time to troubleshoot random circuit mods.

honestly im not really worried about theft

im worried about people who just want to flatten my tires, break or steal small parts, pour paint in or on the car, etc

just general vandal stuff


my car is about 100ft away in the parking lot
i can barely see it but i can hear stuff happening in that area

Something like this comes to mind.

Don't click the link if you're against cartoon violence, or if you like the color green.

lol

something like that