Killswitch: Car security on the cheap. by Mother Natures Son
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I am hopelessly absent-minded. Coupled with the fact that I usually get to school early and often sit in my parking space listening to the radio and mucking about on my computer for a while before going in to class, I often leave the key in the ignition and/or the door unlocked.

Clearly, rather than just trying to remember, I had to find an unnecessarily complex and technology-oriented solution.

Even if you aren't as much of a scatterbrain as I am, car theft is a problem. Alarms are universally annoying and universally ignored. On Star and Low Jack are expensive. How do you avoid coming out to your parking space to find a bit of broken glass and nothing else? Make starting it a complex and arcane ritual beyond the comprehension of the uninitiated.

 
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Step 1: Figuring out the circuit

I puzzled over this problem for some time. One option I've heard is wiring a toggle switch into the fuel injection computer. This would likely confound any thieves attempting to steal the car, as it wouldn't immediately suggest the use of a traditional killswitch. The danger, of course, is that if the switch were accidentally turned off in the course of driving, the engine would die. In my car, a 2002 Toyota Celica, I realized that there was a switch under the dash which prevented the ignition from engaging when the clutch wasn't depressed fully. By interrupting this circuit, I could prevent anyone who didn't know about that switch from starting the car.
technosasquatch says: Jul 25, 2011. 11:33 PM
I might have to try something like this, some tried to steal my car tonight
Ranie-K says: May 1, 2010. 9:05 AM
Just had an idea: You could put a magnet switch under the dashboard, making it impossible to drive the car if you don't put a magnet on a "secret location" on top of the dashboard! This magnet could be hidden in just about anything you'd naturally find in a car. It would have to be "non skid", so it wouldn't fly off when braking or accelerating.
Mother Natures Son (author) says: May 1, 2010. 9:15 PM
Very clever. I like it--I could see disguising the 'key' as a pack of gum,
Ranie-K says: Nov 16, 2010. 2:14 AM
Found an even cooler thing you could install on ebay. I'd hope that this keyfob reader should be able to read your keyfob even if installed under the dashboard:

Becayse of the spam-filer, I can't post a direct link. Just go to ebay and enter this item number in the search field: 170544127916
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DallasDeckard says: Nov 5, 2010. 1:27 AM
Help me understand this better. I know that the switch next to the window switch is a dummy (a stealth switch, as you call it), but what are the other two switches for? I thought you had it hooked up so that if you push the window switch, the car starts, but you switch it again and it doesn't (or you have to hit it each time you start). Can you give me a description of the way this works? Thanks.
twocvbloke says: Aug 16, 2010. 10:52 AM
My dad used to put in secret ignition switches in his cars, one even actually stopped some thieves stealing an old car he had back when he was young, they tried to push start it too, but to no avail. Hidden switches are a good idea, could be anything from a simple SPST switch on the ignition-on wire in the glove box, to a reed switch behind the dash and relay setup with a magnet on your keys, it can save your car from being taken by scrotes who think they can take what they want... :)
lobo_pal says: Apr 29, 2010. 10:24 PM
Also useful if your wife or kid wants to drive your car.
yo man says: Apr 29, 2010. 2:24 PM
crazy cool man! when i leave my old truck in a car park  i pull the
mane spark wire from coil .
crapflinger says: Apr 29, 2010. 10:08 AM
i've seen some pretty complex versions of this idea. my favorite was one that required you to have the left turn signal on, the dome light, and your rear window defroster on at the same time or the car wouldn't start. with creative enough wiring you can make a car REALLY hard to start
Mother Natures Son (author) says: Apr 29, 2010. 12:49 PM
Wow. That is complex...my one worry is that if you stall out, it would take some time to restart. Even with my setup it's a little nerve-wracking in that respect. 
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