paulie102003
Registered User
So picked up my S5 yesterday (no pictures yet but I will get it sorted) however worringly, the dealership wasnt sure if it had keyless entry or not. It does and so I decided to build myself a faraday cage and thought I would document how I did this in case anyone else wished to follow. This is easy, quite cheap, cost me about 20 quid in parts and a few hours of time and is better than those horrible bags that you can buy off certain websites. And yes I know that this doesnt stop anyone breaking into your house - the reality is that if they want your car, they will take it.
I wanted something nice and easy to just throw the keys into at the end of a day, something which will look half decent and not too much like an afterthought, and I hate those bags. So I ordered a cheap wooden box off the internet for a fiver which is about 200mm x 200mm x 150mm tall. Internal dimensions, now, are about 140mmx140mmx90mm. I need to stain it with an oak stain that I have lying about however this is not done as of yet.
The box is a simple pine construction, however it was completely empty. I created an interior wooden frame to force the lid to seal down tightly onto it as per this picture.
After a lot of sanding, I got it to seat nicely, so a solid push seats it, and a gentle tug releases it.
It is best to use copper mesh as copper is really conductive of radio signals, however aluminium works ok, and its quite expensive to order pure copper mesh even from the internet. (Try wrapping your key in aluminium foil and it will block all signals). The basic science behind this is that keyfobs work on approximately the 300mhz range, which is a wavelength which is quite small in size. As it is on the UHF range (ultra high frequency), it can go all the way to approximately 3ghz. The size of these wavelengths are called Decimeters and all frequencies within the UHF range fluctuate from between 1 to 10 decimeters, which, in English, means the size of the wavelength are between approximately 10mm to 1000mm from their peak to their troughs. If these wavelengths are interrupted at any point, the signal fails. So, put a conductive barrier which is less than 10 mm in size, it will interrupt the wavelengths and therefore any signals, meaning they cannot be high jacked.
So, I lined the box with 3 layers of insulation foil, freshly stolen from the ex wifes kitchen drawer. On top of that, I cut and layed 5mm aluminium mesh on the bottom of the box, and on its sides, making sure that I overlapped them by a couple of inche and held in place with some wood staples. I layed 2 layers of mesh, overlapping the holes inbetween the mesh to make it even tighter.
The lid was removed and I created a lip within the lid, to ensure that it would contact with the raised lip on the base and make it as tight a fit as possible, packed it with foil and sealed it.
This then received the same treatment as the base.
A quick trip, down some country lanes in Dynamic mode to my local Hobbycraft to pick up some foam and felt sheets so I could tidy the inside up a bit. The foam was sprayed with contact adhesive onto the mesh/foil, to create a more solid base for the felt. At this stage, the box already worked, I was just tidying it up.
It needs a bit of tidying up and staining however, it now looks like this - a nice place to just throw the keys in after you get home and not worry about any relay attacks. And most importantly, it works - sit in the car and it hasnt got the faintest clue the fob is there
I wanted something nice and easy to just throw the keys into at the end of a day, something which will look half decent and not too much like an afterthought, and I hate those bags. So I ordered a cheap wooden box off the internet for a fiver which is about 200mm x 200mm x 150mm tall. Internal dimensions, now, are about 140mmx140mmx90mm. I need to stain it with an oak stain that I have lying about however this is not done as of yet.
The box is a simple pine construction, however it was completely empty. I created an interior wooden frame to force the lid to seal down tightly onto it as per this picture.
After a lot of sanding, I got it to seat nicely, so a solid push seats it, and a gentle tug releases it.
It is best to use copper mesh as copper is really conductive of radio signals, however aluminium works ok, and its quite expensive to order pure copper mesh even from the internet. (Try wrapping your key in aluminium foil and it will block all signals). The basic science behind this is that keyfobs work on approximately the 300mhz range, which is a wavelength which is quite small in size. As it is on the UHF range (ultra high frequency), it can go all the way to approximately 3ghz. The size of these wavelengths are called Decimeters and all frequencies within the UHF range fluctuate from between 1 to 10 decimeters, which, in English, means the size of the wavelength are between approximately 10mm to 1000mm from their peak to their troughs. If these wavelengths are interrupted at any point, the signal fails. So, put a conductive barrier which is less than 10 mm in size, it will interrupt the wavelengths and therefore any signals, meaning they cannot be high jacked.
So, I lined the box with 3 layers of insulation foil, freshly stolen from the ex wifes kitchen drawer. On top of that, I cut and layed 5mm aluminium mesh on the bottom of the box, and on its sides, making sure that I overlapped them by a couple of inche and held in place with some wood staples. I layed 2 layers of mesh, overlapping the holes inbetween the mesh to make it even tighter.
The lid was removed and I created a lip within the lid, to ensure that it would contact with the raised lip on the base and make it as tight a fit as possible, packed it with foil and sealed it.
This then received the same treatment as the base.
A quick trip, down some country lanes in Dynamic mode to my local Hobbycraft to pick up some foam and felt sheets so I could tidy the inside up a bit. The foam was sprayed with contact adhesive onto the mesh/foil, to create a more solid base for the felt. At this stage, the box already worked, I was just tidying it up.
It needs a bit of tidying up and staining however, it now looks like this - a nice place to just throw the keys in after you get home and not worry about any relay attacks. And most importantly, it works - sit in the car and it hasnt got the faintest clue the fob is there
