motco said:
Here in UK we have a spate of keyless thefts of cars by the use of cloning devices. If your key is accessible from outside your property (in radio terms) it can be read, cloned, and the device used to open and run your car - BMW, Audi, Nissan, whatever brand. The advice is to keep your key(s) in a Faraday cage to render it inaccessible from anywhere outside the 'cage'. Such a 'cage' might be something as simple as a small metal container such as available here to pack and sell larger packs of loose tobacco for pipes or self-rolled cigarettes. Any metallic container (may need to be ferrous, I don't know) with a lid will suffice. This should 'blind' the Leaf key to the proximity of the car.
My key is kept overnight on my bedside table which is upstairs and about 30 - 50 feet from where the car stands on the drive. I am able to lock and unlock the car from there, so I assume that jjeff's advice that the key may be chattering away with the car all night holds true? I'm off to my workshop now to find a suitable container...
Boy that's really sad, the extent to which people will go to avoid real work
and for whatever reason, the UK seems to be a vision of the future of what might happen in other places. Probably because the UK is close enough to countries where they come up with such things but are prosperous enough to have nice cars. I know the UK was where I first read of catalytic converter thefts, several years before the cats were ripped out of our '07 Prius :evil: apparently the #1 car for such thefts due to it having 2 cats and very high quality at that. Now a week doesn't go by when I don't read or hear of someone else getting their cat taken, outside homes while people sleep, in shopping areas while people shop, while people park at work, etc. Not on our street but our suburb or for sure our city, it's gotten out of control!
Anyway back to the question at hand. I just did some tests of the FOB of my '12, '13 Leafs and '07 Prius.
The Prius is easiest to block the sensor, now I'm only going to talk about the proximity sensor as that's what they use to clone, the buttons you push are radio waves and different than the prox system and not what they use to clone your FOB or what communicates with the car, causing the battery to wear down prematurely.
Prius was easiest to shield, a small Altoids tin successfully blocked all prox functions on both front doors and hatch. It did take 2 layers of AU foil to block it, it went through just 1 layer of decent(not ultra-thin) foil.
My '13 Leaf was the next easiest to block the FOB although if you held the Altoids box right next to the door handle and in a certain way, the car would lock/unlock even through the closed Altoids tin. Two layers of AU foil did block the prox though.
My '12 Leaf was the hardest to block, although some of that may have to do with the brand new battery I just put in the FOB a few days ago. The fobs prox easily went through the Altoids tin but it took 3 layers of AU foil to stop it.
Long story short, while an Altoids tin is probably good enough to keep someone from cloning your FOB, unless they were literally inches from it, it doesn't totally stop the prox from getting through. Three layers of decent AU foil does seem to do the trick but would probably be inconvenient to use over and over. I'm guessing if all your trying to do is stop your FOB battery from wearing out too soon an Altoids tin(or a similar metal box with a metal cover) would be fine if you kept it several feet from your car. They probably also sell boxes or even metal-lined small bags? that might even work better than a simple Altoids tin. From the fact the AU foil blocked the FOB and quite well at that, tells me it doesn't matter if the metal is ferrous or not. I do seem to remember reading copper might be good at blocking radio waves and lead blocks things like X-rays but I'm not sure how either these metals would block prox functions.