OT: Electronic coded car locks

[Michael Kennedy]

"Ron" <ron@lunevalleyaudio.com> wrote in message
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N_Cook wrote:
Ron <ron@lunevalleyaudio.com> wrote in message
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N_Cook wrote:
Ron <ron@lunevalleyaudio.com> wrote in message
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William Sommerwerck wrote:
It works, I`ve tried it.
Okay. Please name the car model, the cell phone model, and the remote
control you used.


Vauxhall Zafira and Vauxhall Astra. My mobile was a Nokia, can`t
remember the model, I haven't got it anymore, 3210 sound about right?
I
don't know what my sons mobile was. We tried it several times at
various
distances up to several hundred yards, well out of range of the cars
keyfob which was indoors anyway. The 'remote control' as you put it
was
obviously the ones which came with the cars!

The same set up also resets the alarm of wife's Volvo 945 (has central
locking but not remote, the keyfob justs disables the alarm)

I don't know how it works, but in some cases it does.

Ron(UK)

So let me get this straight. Someone somewhere else in the world uses a
mobile phone to phone you. He uses a keyfob (to a car of the same make
as
yours) near his phone, in conversation mode, and you place your cell
phone
close to your car.


No, it has to be the correct keyfob for the car - the spare one.

I don't know what maximum distance it works over - I doubt country to
country but certainly for us it worked over maybe 250 yards - no reason
it shouldn't be further unless repeaters affect it. We were on two
different networks, so maybe not.

Ron


So what happens if you try a totally unmodified IR remote control near a
cell/mobile? any break through. Nothing I should think but you never
know.
They sometimes break through into an AM radio if very nearby.
I'm thinking of the situation of those non-so-called universal remotes ,
someone somewhere has an original maker's one and you have a learning
mode
one.

I don't see why it should work, but strange things happen. the simple
answer is, try it. Don't some mobiles have infra red data ports?

Ron

What does infra red have to do with anything here?
We're talking about RF not IR.

Anyway, If this were a gamble, I'd put a large sum of money against this
working unless its just using the
cell phone as an antenna for the key fob. Still not going to get more range
than a few meters. Certainally not going to work across the city.

Mike


-Mike

 

[Adrian C]

Michael Kennedy wrote:

Anyway, If this were a gamble, I'd put a large sum of money against this
working unless its just using the
cell phone as an antenna for the key fob.

That could be it. Folks trying this trick are standing close enough to
the car such that the mobile phone with the car remote has its PA stage
energised which by some loose coupling boosts the coverage of that
remote. The mobile held close to the car is probably doing nothing to
aid this.

--
Adrian C

 

[William R. Walsh]

Hi!

One thing that might make this possible (or at least drastically
improve your odds) is the way the receiver handles an "out of
synchronization" situation.

Normally, remotes have to be paired with a given vehicle so that the
rolling codes can be synchronized. However, if precise synchronization
was required, the owner of the car would be very unhappy if they ever
pressed a transmitter button while out of range.

So the receiver will actually accept a code "out of sequence" up to a
certain point. I read somewhere that this is between 128 and 256 codes
out from the current one. I don't know how true that is for sure.

It's not implausible to believe that two vehicles with keyless entry
systems could be "close enough" in terms of how many codes have been
generated and used that a neighboring code from a remote belonging to
a different vehicle could be accepted.

William