Faraday Bag For Key?

[Old_Norm]

Automobile and airplane passenger compartments are essentially Faraday cages. -Wikipedia

Next bullet:

Electronic components in automobiles and aircraft use Faraday cages to protect signals from interference.
-Wikipedia

Why do they need cages, if the vehicle is a cage. Except unless it fails to act as a cage, by the expected performance of using the word.

Because of the many openings in the "cage" (windows, rubber seals, etc.) not all electromagnetic waves will be attenuated or stopped completely. A properly manufactured faraday pouch completely encloses the key fob (in this case) and prevents electromagnetic waves entering or leaving the pouch. I have moved my key fob, in the pouch, all along the dash and doors and tried to start the vehicle. In every case no key was detected. A Mach E is a faraday cage because of its metal construction, not because it was designed to be one.

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[Old_Norm]

I've come up with the ultimate solution.

 

[lesz]

Yes, exact same here; cheap and works prefectly.

Agree. I’ve been using it for over a year and it’s worked 100% of the time.

 

[Jerrytball]

Phone as a key

Ali, I’ve noticed for a couple of days now, and I’ve tested it PAAK. When I take the wife for a walk, I get the umbrella out of the back, phone in my left pocket if I try to open the back, pushing the button with my right hand, it will not open unless I actually turn my hip towards the car. If I go out there right away and just use the left-hand, it opens right up just a little quirk of noticed.

 

[Kamuelaflyer]

Agree. I’ve been using it for over a year and it’s worked 100% of the time.

That’s the one I used. It worked for a bit over a year then stopped working.

 

[AliRafiee]

Ali, I’ve noticed for a couple of days now, and I’ve tested it PAAK. When I take the wife for a walk, I get the umbrella out of the back, phone in my left pocket if I try to open the back, pushing the button with my right hand, it will not open unless I actually turn my hip towards the car. If I go out there right away and just use the left-hand, it opens right up just a little quirk of noticed.

Oh yeah. I get the same thing sometimes. More often than not I have to take the phone out of my pocket. As if my jeans are lead lined. There is an update, “easy entry” that increased the detection radius, but still works better when it’s out of my pocket.

 

[Meljfry]

I have trust issues... lol

But in all seriousness, part of what I like about the door code is that my people know the code and where to find the key. So no matter what happens they can use the car in an emergency. It is a small safety net for remote areas without decent cell service.

But for normal day to day Im going to test out PAAK!

I totally agree with the door code. Believe it or not, that is one reason that I got the MachE. I had an Edge that I really liked, traded it in for a 2024 Edge and then I realized that it didn't have the door code anymore. I bugged me ALL the time. Traded it for the MachE after only 7 months. So far, under 2 weeks, love it!

 

[bbulkow]

One of the reasons I love Ford vehicles is the exterior keypad. I do a few outdoor sports where it is handy to leave the key in the vehicle and simply use the exterior keypad to get back in. But it seems like leaving the key in the Mach e would let anyone get into a take the car... not good.

Im wondering if anyone has tried to use a faraday case or bag for the key? Im hoping this would let me leave the key in the car but not communicating with the car.

Yes. This is my backstop when everything fails. I also have a fob in the car on the very rare occasion when I need to valet, just pop it out of the pouch. Works great. I have one of the amazon ones too.

 

[cdodge]

Since the car is already a faraday cage, sticking it into another faraday cage (a cheapo chinese made pouch), does not do anything. It's almost like giving a placebo to a hypochondriac.

If you guys don't think that the car is a faraday cage, then we have a different discussion.

where is the faraday cage? I have been using the pouch with no issues but if there is something in the car that gives me the same functionality, I would use that instead.

 

[Old_Norm]

where is the faraday cage? I have been using the pouch with no issues but if there is something in the car that gives me the same functionality, I would use that instead.

There is no physical cage per se. The entire car is a Faraday cage because it is made of metal. See https://sky-lights.org/2018/04/30/qa-your-car-is-a-faraday-cage/

 

[HuntingPudel]

I crack up when people say that a metal container is a Faraday cage. There are so many gaps and openings in an item such as an automobile that the rate of attenuation is pretty bad. In some instances, a signal may be magnified. I say this as someone with many years of Electromagnetic Compatibily engineering experience. ??

 

[Old_Norm]

I crack up when people say that a metal container is a Faraday cage. There are so many gaps and openings in an item such as an automobile that the rate of attenuation is pretty bad. In some instances, a signal may be magnified. I say this as someone with many years of Electromagnetic Compatibily engineering experience. ??

Would you put a piece of equipment that required unfettered access to electromagnetic waves from a source, inside an automobile or inside a non-metallic enclosure?

 

[HuntingPudel]

Would you put a piece of equipment that required unfettered access to electromagnetic waves from a source, inside an automobile or inside a non-metallic enclosure?

Nonsequitur question. ?‍?

 

[Old_Norm]

Nonsequitur question. ?‍?

And that prevents you from answering it why? Don't you know which you should do?

 

[steve.panse]

Let's go through this in order:

1. You and the fob are both inside the car. The car can be unlocked with the fob. This is expected.
2. The fob is locked inside the car. You then unlocked the car using the 2nd fob from out side. This is is expected.
3. The fob is locked inside the car. You then unlocked the car using Fordpass or key pad code. This is expected.

This is what you didn't try. Lock the fob in the car. Make sure your phone and the other fob are out of range completely. Make sure that all windows are fully rolled up. Press the door entry button. Does the door open? If not, the car is operating as a faraday cage and exhibiting expected behavior.

The car is not a faraday cage. Otherwise your cell phone wouldn’t work inside. RF can pass through the glass windows.

The car has antennas everywhere inside and outside, so it knows if the key is inside or outside the car at all times. When you lock a fob inside the car, it remembers that, and won’t let you unlock the car from the outside with it. A valid fob must be detected OUTSIDE the vehicle for it to unlock when you press the door open button. Software enables it, not because of a faraday cage effect.

This is right, the car body really is a terrible faraday cage for the radio frequencies (wavelengths) used by key fobs. The window openings are much larger than the mesh size needed to shield transmission.

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