"Faraday Cage" for storing extra fob in the car
11-28-09, 08:57 PM
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"Faraday Cage" for storing extra fob in the car
Just took delivery of my red 2010 ES 350 today. Yay! Love it.
One challenge:
I use valet parking at the airport (I travel every week). I don't want to hand over my keyfob to the parking attendant, because if they lose it while I'm gone, now we have no way to enter or start the car (I've had this happen in the past). So I want to keep MY keyfob with me when I fly out.
I want to be able to store the spare keyfob inside the car, so that I don't have to remember to bring it with me every time I want to use valet. Obviously with these electronic keyfobs, this is a problem.
So I'm thinking of making a "faraday cage" for my spare fob, so I can store it inside the center console and have it handy when I need it. I know it works--I wrapped the fob in aluminum foil, walked up to the car with it, and presto--could not open the locked door. Unwrap foil just a tad, and presto--now I can open the door.
I guess my question is, what detrimental effect would storing the fob inside the foil have on the fob? Would it fry the battery sooner than usual, or something?
One challenge:
I use valet parking at the airport (I travel every week). I don't want to hand over my keyfob to the parking attendant, because if they lose it while I'm gone, now we have no way to enter or start the car (I've had this happen in the past). So I want to keep MY keyfob with me when I fly out.
I want to be able to store the spare keyfob inside the car, so that I don't have to remember to bring it with me every time I want to use valet. Obviously with these electronic keyfobs, this is a problem.
So I'm thinking of making a "faraday cage" for my spare fob, so I can store it inside the center console and have it handy when I need it. I know it works--I wrapped the fob in aluminum foil, walked up to the car with it, and presto--could not open the locked door. Unwrap foil just a tad, and presto--now I can open the door.
I guess my question is, what detrimental effect would storing the fob inside the foil have on the fob? Would it fry the battery sooner than usual, or something?
11-28-09, 09:37 PM
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Remove the battery from the spare fob, place spare fob and battery in a plastic baggie in your storage place inside the car before leaving. Upon return, pop battery into spare fob and you should be good to go. No worries.
11-28-09, 09:47 PM
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Well your idea is valid...you've got the leaving/returning part switched but that doesn't matter.
The question concerning your recommendation is: if one leaves the battery out of the fob for an extended period, does the Fob then have to be "re-paired" or re-programmed? Will it lose its ability to link to the car?
11-28-09, 10:00 PM
#4
Storing the fob in foil seems like I good idea, if it actually works.
I believe the interface is an active-type of RFID.
Foil should not damage the fob or lead to higher power consumption levels.
My advice comes from 14-years as an electrical engineer.
I have the similar problem. I wan't to hide a spare fob in the vehicle.
One idea is to hack the fob and add a micro slide switch so I can turn on and off the fob easily.
I believe the interface is an active-type of RFID.
Foil should not damage the fob or lead to higher power consumption levels.
My advice comes from 14-years as an electrical engineer.
I have the similar problem. I wan't to hide a spare fob in the vehicle.
One idea is to hack the fob and add a micro slide switch so I can turn on and off the fob easily.
11-28-09, 10:11 PM
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Lexus engineers are smarter that we all are...
You CAN lock the second fob inside with battery and without "Faraday cage".
Just put it in the glove box and lock it with the mechanical key.
Now you can lock the car with "Lock" button on the other fob.
The button on the door handle would not lock the car with fob inside, but the other fob buttons do lock/unlock the doors.
Then, keep the mechanical key and give the fob to anyone. Just tell them to use the buttons on the fob, not the door sensors/buttons - they do not work when there is a fob inside.
If the idiot loses the fob, you can unlock the door and then the glove box with the mechanical key and get your spare fob.
You CAN lock the second fob inside with battery and without "Faraday cage".
Just put it in the glove box and lock it with the mechanical key.
Now you can lock the car with "Lock" button on the other fob.
The button on the door handle would not lock the car with fob inside, but the other fob buttons do lock/unlock the doors.
Then, keep the mechanical key and give the fob to anyone. Just tell them to use the buttons on the fob, not the door sensors/buttons - they do not work when there is a fob inside.
If the idiot loses the fob, you can unlock the door and then the glove box with the mechanical key and get your spare fob.
11-28-09, 11:01 PM
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Lexus engineers are smarter that we all are...
You CAN lock the second fob inside with battery and without "Faraday cage".
Just put it in the glove box and lock it with the mechanical key.
Now you can lock the car with "Lock" button on the other fob.
The button on the door handle would not lock the car with fob inside, but the other fob buttons do lock/unlock the doors.
Then, keep the mechanical key and give the fob to anyone. Just tell them to use the buttons on the fob, not the door sensors/buttons - they do not work when there is a fob inside.
If the idiot loses the fob, you can unlock the door and then the glove box with the mechanical key and get your spare fob.
You CAN lock the second fob inside with battery and without "Faraday cage".
Just put it in the glove box and lock it with the mechanical key.
Now you can lock the car with "Lock" button on the other fob.
The button on the door handle would not lock the car with fob inside, but the other fob buttons do lock/unlock the doors.
Then, keep the mechanical key and give the fob to anyone. Just tell them to use the buttons on the fob, not the door sensors/buttons - they do not work when there is a fob inside.
If the idiot loses the fob, you can unlock the door and then the glove box with the mechanical key and get your spare fob.
04-17-15, 11:05 PM
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There’s one place already selling “military spec” car key faraday cages for this exact purpose: http://www.carkeycage.com
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04-18-15, 04:24 AM
#8
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Lexus engineers are smarter that we all are...
You CAN lock the second fob inside with battery and without "Faraday cage".
Just put it in the glove box and lock it with the mechanical key.
Now you can lock the car with "Lock" button on the other fob.
The button on the door handle would not lock the car with fob inside, but the other fob buttons do lock/unlock the doors.
Then, keep the mechanical key and give the fob to anyone. Just tell them to use the buttons on the fob, not the door sensors/buttons - they do not work when there is a fob inside.
If the idiot loses the fob, you can unlock the door and then the glove box with the mechanical key and get your spare fob.
You CAN lock the second fob inside with battery and without "Faraday cage".
Just put it in the glove box and lock it with the mechanical key.
Now you can lock the car with "Lock" button on the other fob.
The button on the door handle would not lock the car with fob inside, but the other fob buttons do lock/unlock the doors.
Then, keep the mechanical key and give the fob to anyone. Just tell them to use the buttons on the fob, not the door sensors/buttons - they do not work when there is a fob inside.
If the idiot loses the fob, you can unlock the door and then the glove box with the mechanical key and get your spare fob.
04-18-15, 08:21 AM
#9
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Originally Posted by zhivuyatut View Post
Lexus engineers are smarter that we all are...
You CAN lock the second fob inside with battery and without "Faraday cage".
Just put it in the glove box and lock it with the m......
well I just had to run out and try this and it works
good catch zhivuyatut
Lexus engineers are smarter that we all are...
You CAN lock the second fob inside with battery and without "Faraday cage".
Just put it in the glove box and lock it with the m......
well I just had to run out and try this and it works
good catch zhivuyatut
04-18-15, 04:12 PM
#10
I would not recommend doing this, even though it seems like a good idea.
Let's say someone broke into the car - either by somehow unlocking the door mechanically or knocking out a window. Since the fob is inside, the car won't care either way - thief on a whim just tries the start button (maybe he's just there to take some personal effects) and boom, dash lights light up.
Even if someone doesn't break in, you could accidentally leave the car unlocked and it becomes a crime of opportunity.
Let's say someone broke into the car - either by somehow unlocking the door mechanically or knocking out a window. Since the fob is inside, the car won't care either way - thief on a whim just tries the start button (maybe he's just there to take some personal effects) and boom, dash lights light up.
Even if someone doesn't break in, you could accidentally leave the car unlocked and it becomes a crime of opportunity.
04-18-15, 04:39 PM
#11
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I would not recommend doing this, even though it seems like a good idea.
Let's say someone broke into the car - either by somehow unlocking the door mechanically or knocking out a window. Since the fob is inside, the car won't care either way - thief on a whim just tries the start button (maybe he's just there to take some personal effects) and boom, dash lights light up.
Even if someone doesn't break in, you could accidentally leave the car unlocked and it becomes a crime of opportunity.
Let's say someone broke into the car - either by somehow unlocking the door mechanically or knocking out a window. Since the fob is inside, the car won't care either way - thief on a whim just tries the start button (maybe he's just there to take some personal effects) and boom, dash lights light up.
Even if someone doesn't break in, you could accidentally leave the car unlocked and it becomes a crime of opportunity.
05-28-15, 09:56 AM
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06-02-15, 04:54 PM
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Amazon sells a pouch for cell phones to block tracking. It works for key fobs as well and is very affordable. Great if your car is parked in your driveway or curb side and you leave your key nearby.
01-13-16, 08:57 PM
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I'm a little surprised *anyone* would want to leave a spare key in the car. I smash a window and steal your car? No thanks.
Why not just attach both key fobs to your key chain?
Why not just attach both key fobs to your key chain?
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