Keyless entry remote fob anti theft Idea

[guest8810]

As the criminal fraternity find keyless entry a gift from heaven, or should I say from car manufacturers .
I wondered if it is possible to simply turn the pesky thing off, this would certainly upset the applecart so to speak, but as I am not an electrical genius and other than removing the battery, I thought that the combined mental might of this excellent forum could come up with a good idea.??
Heres hoping.

[peteo48]

I am no expert either but I suspect the system is so wired in to everything on the car, including the starter button, that it would not be possible.

The article I quoted on another thread indicated that it was a good idea to keep your keys in some sort of container which would help block the signal when you were indoors and in bed. A safe perhaps? That said the problem with thieves cloning keys by "talking" to them from outside seemed to apply to upmarket cars like Range Rovers.

[guest8810]

I am no expert either but I suspect the system is so wired in to everything on the car, including the starter button, that it would not be possible.

The article I quoted on another thread indicated that it was a good idea to keep your keys in some sort of container which would help block the signal when you were indoors and in bed. A safe perhaps? That said the problem with thieves cloning keys by "talking" to them from outside seemed to apply to upmarket cars like Range Rovers.

I store mine in the microwave ,but it  is very very heavy to carry around.

[Jocko]

I store mine in the microwave ,but it  is very very heavy to carry around.

Do you have a long extension cable?

[sparky Paul]

I store mine in the microwave ,but it  is very very heavy to carry around.

Seriously though, I've seen this tip before, and I guess it would be effective... but it wouldn't be the first time I had turned the microwave on by mistake, before putting something in it. A second or two would surely be enough to blitz the pcb in the key fob.

[ColinS]

I am no expert either but I suspect the system is so wired in to everything on the car, including the starter button, that it would not be possible.

No doubt it would be possible to isolate the circuit with a hidden switch that you toggled once inside the car.  But what about the alarm?  That is indubitably interconnected.

[Jocko]

A microwave is just an earthed metal box. All you need is a metal box (Golden Virginia tin springs to mind), solder or bolt a wire to it, a single core green/yellow would be ideal, and wire the other end to the earth terminal of a 13A plug top. You plug it in (no need even to switch the socket on), and put your fob in the box.
I made a similar thing but with a crocodile clip instead of a box. When I play my guitar through my laptop (not earthed), I connect it to the metal sheath of the jack plug and that earths the guitar and cuts out spurious noise.

[culzean]

Seriously though, I've seen this tip before, and I guess it would be effective... but it wouldn't be the first time I had turned the microwave on by mistake, before putting something in it. A second or two would surely be enough to blitz the pcb in the key fob.

I would measure the FOB survival time in milliseconds -----------


I guess the car thefts at home are because a lot of people either throw the car keys / FOB on the hall table or in their pocket hanging up near front door,  just take the FOB upstairs as far away from car / driveway as possible.  Apparently if the car is within range of the FOB when parked strange things can happen including flattening the car battery - some hybrids have started themselves up when they sensed car battery getting low..  Seriously when car is within range of FOB on some vehicles the car is 'awake',  but some don't try to talk to FOB until a door handle is touched..

[sparky Paul]

Seriously though, I've seen this tip before, and I guess it would be effective... but it wouldn't be the first time I had turned the microwave on by mistake, before putting something in it. A second or two would surely be enough to blitz the pcb in the key fob.

I would measure the FOB survival time in milliseconds -----------

Indeed, but I wouldn't be able to turn the microwave back off that quick, it would take a second or two for the the brain cells to react.

[guest8810]

Seriously though, I've seen this tip before, and I guess it would be effective... but it wouldn't be the first time I had turned the microwave on by mistake, before putting something in it. A second or two would surely be enough to blitz the pcb in the key fob.

I would measure the FOB survival time in milliseconds -----------

Indeed, but I wouldn't be able to turn the microwave back off that quick, it would take a second or two for the the brain cells to react.

In my earlier post I said that I store my Fobs in the Microwave,I omitted to say at Night whilst tucked up etc, also that Always prior to placing Fobs into Microwave I Turn it Off at wall and UNPLUG IT the lead and plug is then placed behind Microwave to ensure that it is not Turned on etc hope that this explains the situation the logic behind using MICROWAVE is that if it shields the user from any harm of escaping Microwaves, then it should stop any escaping emissions from my FOBS BINGO

[Jocko]

UNPLUG IT

The microwave only stops emissions because the case is earthed. If you unplug it is no longer earthed and you would be as well putting the fob in a biscuit barrel, or any other tin box.

[JimSh]

UNPLUG IT

The microwave only stops emissions because the case is earthed. If you unplug it is no longer earthed and you would be as well putting the fob in a biscuit barrel, or any other tin box.

Why does it have to be earthed? Surely any metal box would do.
By coincidence my wife switched on microwave accidentally today while working in the kitchen.

[Jocko]

Why does it have to be earthed? Surely any metal box would do.

An earthed Faraday Cage works better because if the cage is grounded, the excess charges will be neutralised as the ground connection creates an equipotential bonding between the outside of the cage and the environment, so there is no voltage between them and therefore also no field. The inner face and the inner charge will remain the same so the field is kept inside.

[culzean]

In my experience a Faraday cage does not need to be earthed with low power signals,  in high power shielding they are earthed, but mainly for safety to stop a charge build up on the surface of the cage.  The idea with a Faraday cage is that the external signals are routed around the outside conducting material and leave a void inside with no electrical charge.  Any opening in a Faraday cage needs to be no larger than 1/8 of the shortest ( highest frequency ) wavelength you are trying to block ( that is why you can see inside a microwave even with door closed because the door has a metal screen with thousands of tiny holes punched into it,  light can get through but not longer the wavelength length electrical waves ).  Domestic Microwaves work on around 2.5Ghz,  and keyless entry works on about 433Mhz,  so if the high power ( 900 watts + ) microwaves cannot get out of the microwave cabinet, there is no way the low power 433Mhz ( measures in Milliwatts ) is gonna get in,  earthed or not.

Copper or Mumetal or even aluminium works very well for faraday cage,  because it is good electrical conductivity rather than magnetic properties that you are looking for.

[sparky Paul]

Just use an old tobacco tin, that will do the job.

Here's another trick I use, being the forgetful type. If you walk away and have forgotten to lock your car, but then find you've walked too far and are out of range, touch the fob to the side of your cranium and press the button. It might eventually fry your brain, but extends the range of the plipper considerably.