A wireless automotive kill switch?

October 5, 2006 5:57 AM

I'm planning on installing a kill switch in my car, and thinking about wireless options.

Rather than installing a mechanical switch, I was wondering if there is any sort of system where, for example, a keytag worn on the belt would disable the kill switch when it got within range.

So, I get out of the car, walk away, the car is immobilised. I get into the car, and bingo, the ignition works. Is this doable? I've done a bit of searching but I'm not entirely sure what search terms I need to find such a thing.

I read about this being a function of some newer cars, perhaps the Prius?

I don't want a standard remote clicker thing, but something that takes nothing more than my presence to activate.

posted by tomble to Travel & Transportation (16 answers total)

My father had one of these. It was annoying as hell. The car would always take approximately five seconds longer to recognize his presence than he would like.

A mechanical switch has its advantages.
posted by BackwardsCity at 6:07 AM on October 5, 2006

Seems like kind of dangerous idea. One dead battery in your remote key and you're dead on the freeway. That would kill your motor and your power steering.
posted by doctor_negative at 6:07 AM on October 5, 2006

One dead battery in your remote key and you're dead on the freeway. That would kill your motor and your power steering.

Presumably you'd kill the starter with the switch.
posted by mendel at 6:10 AM on October 5, 2006

Mendel is right, but still, you can get trapped on the wrong end of a trip. I think that happened to my father once, too.
posted by BackwardsCity at 6:42 AM on October 5, 2006

that's why you should try to use passive rfid instead.
posted by noloveforned at 6:46 AM on October 5, 2006

Response by poster: Passive RFID is the idea. Didn't someone get implants to open doors when they got near? That's the sort of thing I had in mind.

"That would kill your motor and your power steering."

We don't need no steenking power steering! (The car in question is 40 years old, but I like the idea of a touch of hi tech in it).
posted by tomble at 6:51 AM on October 5, 2006

Don't most modern cars do this already with RFID or somesuch in the keys themselves?
posted by antifuse at 6:56 AM on October 5, 2006

Best answer: In newer cars this is done with passive RFID chips in the keyfob, which don't require batteries (they generate power from the radio signal sent by the sensor).

Any wireless key introduces additional privacy and security risks compared to physical keys. This isn't just theoretical; RFID immobilizers used in millions of cars have been cracked, and thieves are apparently stealing cars by eavesdropping on RFID signals.
posted by mbrubeck at 6:57 AM on October 5, 2006

Simple is always better in my book. Wireless doodads and whatnot just complicate the situation, adding more points of failure.

Consider one of these. It’s essentially a dongle. Each one is randomized, and supposedly there is no skeleton key. Several important wires run through the unit, such that the car will not start without the dongle in place.
posted by clord at 7:26 AM on October 5, 2006 [1 favorite]

Best answer: I have a mechanical killswitch, and sometimes something goes wrong with them (which can result in a dramatic appearance of engine failure in the middle of an intersection, for instance). I would personally want to minimize the chances of this, and a mechanical killswitch is much more simple than this wireless thing.

Presumably you'd kill the starter with the switch.

At least some (mine) are wired so they would kill the engine.
posted by advil at 9:18 AM on October 5, 2006

Consider one of these. It’s essentially a dongle.

Piggyback: do insurance companies recognize the claims made by Ravelco? Will getting one of these installed lower your insurance as much as getting an alarm system, window etching, lo jack, etc.? More? Less?
posted by PinkStainlessTail at 9:47 AM on October 5, 2006

I suggest only using a kill switch if you're tracking the car. The wireless idea is foolish (will lead to electrical problems etc)...

Kill switches can be a hassle, but they can also save your life...
posted by stratastar at 11:10 AM on October 5, 2006

Seconding Clord on the Ravelco install. I have one too and feel pretty comfortable with it, having had one car stolen before. The proof is in the pudding, though - no one has TRIED to steal my car since getting it installed. That said, car thieves are smart. A kill switch is not going to slow them down much, RFID or no. All they have to do is find it and close the circuit around it.
posted by autojack at 11:39 AM on October 5, 2006

Best answer: "The World's Best DIY Immobilizer"

Hidden, magnetic. Can be used to disable a number of circuits, the article has brief commentary/ideas for which circuits to disable.
posted by RikiTikiTavi at 12:25 PM on October 5, 2006

I read an article the other day which I can't find about this. A woman had a car with one of these, and her dog swallowed it. In order to start the car, she had to put the dog in the front seat with her.
posted by MrZero at 2:41 PM on October 5, 2006 [1 favorite]

I rented a '06 Corvette a couple weeks ago that had exactly this. The doors wouldn't unlock, nor would the starter activate, until the keyfob was in range.

Ironically enough, something near the rental lot consistently interfered with the radio signal; I had to wave the fob all over the place, waiting for the starter button to turn green so I could start the car. More trouble than it was worth.

In addition, I read recently (possibly on the green?) that if your car has one of these and gets stolen anyway, your insurance company will accuse you of collusion and not pay because of the supposedly infallible nature of the device, despite the fact that third parties claim to be able to crack them relatively easily.
posted by ikkyu2 at 6:30 PM on October 5, 2006