In article , dennis@home
scribeth thus
On 25/07/2018 22:12, tony sayer wrote:
In article , Andy Burns
scribeth thus
The Natural Philosopher wrote:

The ONLY thing that actaully has made sense is the system whereby
someone stands betwen the car owner and the car, and relays at a
strength high enough to unlock the car, and presumably to drive for 50
yards before they lose signal and the car detects there is none and stops.

Once the car starts, it stays running, even if loses contact with the
key ... don't you think it might be a bit dangerous if it shut the
engine off in lane3 of the M1 when the fob's battery voltage dropped
below some threshold?


I suppose if the fob was purely passive inductive that bit wouldn't be a
problem then?..


Unless you put it next to a rfid blocking wallet, or the keys move into
the wrong place and mask the signal, or the handbag falls over and the
seat frame blocks the signal or ...

All of which could affect the one with batteries too.


FWIW a friend has a Renault which has a flat key fob thats a bit bigger
than a credit card it does open the car by radio frequency but to start
the car it goes in a slot on the dashboard then a conventional starter
button is used ..

--
Tony Sayer