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car anti-theft device idea

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doubleM

New Member
i have an idea for anti-theft and carjacking. i want to make a timer circuit to cut off the fuel pump. no fuel=no start. i think this would be the best way. and it doesnt hurt anything.
now i would kill anybody who messed with my stuff. i drive a muscle car ive put alot of work into and im not about to let some scumbag take it from me without a fight. but in some situations, youre not able to fight or disarm the person. the best thing to do is give them what they want and let it go.

hypothetical situation:
your in your car stopped...guy comes up to the window wielding a gun, (keeping his distance...he knows what hes doing) and tells you to get out of the car. you have no choice but to give him the car or die. but before you get out you flip the secret switch, activating the timer switch. the thief drives off but then the car quits because of the fuel pump cutoff.

this puts distance and time between you and the thief so he cant get mad and shoot you. you have time to call the cops. when he cant get it started he will just panic and leave the car.
this would also work if someone tried to hot wire it. each time you leave the car you flip the fuel pump swtich, turning it off....no start. only other way to steal the car would be to put it on a roll back truck.


so how would i build a circuit that would control this? i keep thinking timer relay of some sort but i dont know anything about them. i could tie it in with the fuel pump relay circuit. can somebody give me an idea on how to build this?
 

Externet

Active Member
Hi.
A company did build a gadget like that, but mechanical. I believe it is MulTlock. It looks like a high/low beam floor switch, it is meant to be placed under the carpet by the driver feet. When forced to exit, stepping on it latches the fuel closed. Can be unlatched only with a key. The fuel lines under the floor pan, and the car has fuel enough in the bowl to starve at the next corner. Was commercialized before fuel injection.

I had six or seven gadgets against crooks in my car, to protect windows, wheels, ignition, shifterlock, door siren, round key, even a sound activated CB beacon.

Another way to do your timer is to wear a magnet in a backpocket and a sensor under the upholstery. When your butt is not there, fuel shuts off in 30 seconds. Sometimes you have no time to think/react on a carjack.

Miguel
 

kpatz

New Member
I'd go longer than 10-15 seconds, probably a minute or three. 10-15 seconds, the car may stall before the carjacker leaves your sight, and is still in shooting range.

You'll want to make the cutoff semi-permanent too. You don't want it resetting if the thief turns the ignition off/back on, which a simple timer would do. Maybe wire it so it blows the fuel pump fuse when it triggers.

There could be safety issues as well, such as if the car stalls in an intersection. I don't care much about the welfare of the scumbag that stole the car but the car itself could end up wrecked... maybe a better solution is to have the hidden switch trigger a circuit that kills the fuel pump after the car is shut off. Thus, the jacker gets away, stops for a beer (or whatever), then they get back in and the car won't start. Maybe combine that with a timer... fuel gets cut off next time the car is shut off, or after 5 minutes, in case they just keep driving.

I've often had ideas for things like this too. If I were to do it, I'd have a little fun with it (using a microcontroller). Perhaps I'd give a warning by stalling the engine but allow it to be restarted once or twice before it dies completely. Or even modulate the pump so that the car starts or runs like an old jalopy. Or have it gradually kill the engine by cycling the pump on and off, with the off intervals increasing in time, so the car sputters, coughs, and dies. Make the carjacker think he got a POS and he leaves it on the side of the road.

Or for some real fun: after the car stalls and the thief tries to restart it, have the lights start flashing and the horn blowing. That should get some attention.
 
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doubleM

New Member
great ideas thanks. i just guessed 15 seconds....because my car would be gone in 60 lol...if they really stomped it. i dont want them to get too far away...
 

robo_boy

New Member
great ideas thanks. I just guessed 15 seconds....because my car would be gone in 60 lol...if they really stomped it. I dont want them to get too far away...
hey!

Man i have designed a such thing, why dont u just put out some kind of circuit material along with a wireless circuit, which takes signal from ur transmitter and actualy switches off the engine and closes the side glasses on ur transmission message....

Instead a mobile circuit is also a good idea!
 

kpatz

New Member
actually, the ultimate carjacking deterrent is to rig the airbags so they deploy once the carjacker starts driving off in the car... ;)
 

mneary

New Member
actually, the ultimate carjacking deterrent is to rig the airbags so they deploy once the carjacker starts driving off in the car... ;)
Have you purchased replacement airbags recently? :eek:

Not to mention the legal/liability implications of injuring the poor innocent-until-proven-guilty, my-son-would-never-do-this carjacker? :confused:
 

mneary

New Member
Think this one through, kids. You just escaped with your life. You want to put your life back in danger for the car?

Must be a nice car to be willing to die for.
 

kpatz

New Member
Have you purchased replacement airbags recently? :eek:
They're cheaper than replacing the entire car. ;)
Not to mention the legal/liability implications of injuring the poor innocent-until-proven-guilty, my-son-would-never-do-this carjacker? :confused:
Ok, a disclaimer sticker on the window ought to do it: "Owner assumes no responsibility for any injury or death resulting from attempting to steal this vehicle". That goes for injuries given by the car's owner (hope the carjacker doesn't plan on reproducing afterward...) or by countermeasures installed in the car.

Anyone who carjacks deserves any "injury" they get... and if your son does it, guess what, you just discovered that he's a scumbag! ;)
Think this one through, kids. You just escaped with your life. You want to put your life back in danger for the car?

Must be a nice car to be willing to die for.
If you're a carjacker, would you rather have grand theft auto on your record, or murder? With a few minutes delay before the car stalls or whatever, you'll likely have long since left the area and called the police.

That said, I don't have any anti-carjacking countermeasures installed in my car. But I like to discuss hypothetical ways to torture the scum of the planet.
 
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doubleM

New Member
well i dont think the airbags deploy idea would work for me...too much trouble. it would be f'n hilarious though. messing with airbag wiring is risky too.

yeah i would be all for sadistic ways to torture thieves lol. like electric shock, fire, hidden gun pointed at driver, my pit bull in the back seat....etc.
 

mneary

New Member
In the spirit of fantasy....

Yeah, locking the doors, rolling up the windows and cutting off the fuel pump sound like fun. I would wire all this to the 'panic' button on my remote control but oops that's the first thing the carjacker would have taken.

Maybe re-wire the car so it won't start unless the 'panic' button *is* pressed first.

A friend reprogrammed his ECU so he had to tap a code into the gas pedal before it would start. It had a "valet mode" with a really low speed limit. A bunch of really smart people reverse engineered the ECU. Not a project for just anybody.
 

Mr RB

Well-Known Member
Nah if it's fantasy... A couple of sticks of TNT under the driver's seat, and a well insured car. :D

Part of the problem with the world today is they lock all the scumbags up in "federal scumbag school" instead of executing them.
 

shokjok

Member
What good is airbag deployment when the car is still driveable after airbag deflation? You may want to install two timers, one triggered by a magnetic switch, and the other time-delayed to kill the starter and activate the horn and lights.
 

tcmtech

Banned
Most Helpful Member
actually, the ultimate carjacking deterrent is to rig the airbags so they deploy once the carjacker starts driving off in the car...
Nope the best deterrent is to drive something that absolutely no one else would want for any reason. :p
 

cowboybob

Well-Known Member
Most Helpful Member
With ya there, tcmtech.

I tell people, rude enough to notice, that the dirt on the car is protecting the wax...
 
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