Find lost keys via RFID?

[tinanbran]

Curious is anyone has found a app that works to find lost or misplaced keys for Tesla's? I would think it could be done using the RFID chip? May not tell you where but would tell you its within an area? Came to me this morning as I misplaced my key and I spent the morning tracking it down

 

[Boourns]

Some people have used a FLIR attachment to their phones. See here: Fob missing somewhere inside Model X - any guesses?

 

[Max*]

Isn't the key fob not transmitting any RFID (i.e. it's passive), unless you press the button? So unless you press the button, you won't be able to find it.

I don't think it's like the car, which is always listening.

 

[Science fan]

Isn't the key fob not transmitting any RFID (i.e. it's passive), unless you press the button? So unless you press the button, you won't be able to find it.

I don't think it's like the car, which is always listening.

But, if the car is always listening, then does it not follow that the fob is always talking? Or is it that the car actively sends out a signal to which the fob replies, in which case the fob would then also be listening. In either case, the fob should be detectable by a nearby RFID-based locating device. Just saying.

 

[Max*]

But, if the car is always listening, then does it not follow that the fob is always talking?

That's not the way I understand it. RKE would only transmit data for a button press.

Think TV remote control. The TV is always listening, but your remote control isn't always talking. You can test this by pointing a camera at it (standard camera detects the IR in the remote control), and you won't see anything. Keep pointing the camera, and press a button and you'll see a burst of light.

Now the Tesla is not a standard RKE. I don't know how they do it. They could have the fob be always talking, but that seems like a waste, even in low energy scenarios. They could have the fob always listening, and have the car transmit and listen (so that when you approach the car, the handles present. And when you're in the car, the car starts). Seems always listening and transmit when asked (or button press) would use less batteries.

I'm sure there are people who have taken the fob apart who could end the speculation.

Or is it that the car actively sends out a signal to which the fob replies, in which case the fob would then also be listening.

This is possible, and the more I think about it, this is likely.

For RKE this isn't necessary, but to start the car, the fob has to receive a signal stating that I'm here in the car. It's instant, so it's possible the fob is always talking. Or the fob is always listening too. Or something completely different.

In either case, the fob should be detectable by a nearby RFID-based locating device. Just saying.

Unless it's always talking, I'm not sure it's possible. Just saying.

If it's always listening, it's probably listening to the correct encrypted message from the car. So that doesn't help either.


If it were so simple, I'm sure someone would've come up with something by now. RKE has been around for decades. And people have been losing keys even longer. That's why there are passive RFID stickers for things, that's why there are bluetooth tiles for keys, etc. Those are easily done. Not sure about the car key homing device.

 

[Saghost]

The fob has passive RFID hardware too, though - so it works with a dead battery if pressed to certain areas of the car. Maybe that could work if the phone can stimulate it somehow?

 

[Max*]

The fob has passive RFID hardware too, though - so it works with a dead battery if pressed to certain areas of the car. Maybe that could work if the phone can stimulate it somehow?

I've heard people claim this, but then i've heard the same people say that when the battery is ACTUALLY dead (not almost dead) placing the key fob on the windshield does not work.

Can anyone confirm?

 

[Max*]

How do you lock the car with a dead key fob battery?

Here ya go. Which leads me to believe it does not have a passive RFID chip.

 

[CHG-ON]

I have one lost somewhere in my house. I expect somebody will find it well after I am dead and wonder what that relic is!

 

[GTJacket02]

Stumbled across this thread looking for ways to find my Tesla key. Are there any better ways today to find a lost keycard? Don’t these use NFC? Hoping there is an app or something.

 

[rooter]

The fob has passive RFID hardware too, though - so it works with a dead battery if pressed to certain areas of the car. Maybe that could work if the phone can stimulate it somehow?

Right. The radio transmission (US - 315MHz) when a button is pressed is distinct and separate from its RFID functionality. Tesla anticipated that there would be times when a fob's battery is dead so included the RFID functionality.

RFID works by a loop antenna transmitting an activate signal which is strong enough to also power the RFID chip in the fob. There are apps, but it's doubtful that any could cause the phone to put out a signal powerful enough to wake the fob. Hope someone proves me wrong; I too have a key lost somewhere in the house, which archeologists will come across in some future millennium.

Great idea.

 

[GregHudson]

Isn't the key fob not transmitting any RFID (i.e. it's passive), unless you press the button? So unless you press the button, you won't be able to find it.

I don't think it's like the car, which is always listening.

From my experience using an NFC ring on my finger, my Model Y is NOT always listening (or transmitting). No amount of tapping on the B pillar will open the car BUT... I've found if I press my thumb on the door handle, the car wakes up, the screen is awake, and now my NFC ring works every time. I found this out after many many hours of testing and frustration... BTW, NFC does not transmit, it is a PASSIVE device and only reacts to an NFC transmitter, such as the one in the drivers side B pillar. Can anyone corroborate my findings please ?