Electronics > Projects, Designs, and Technical Stuff
Sensing an RFID car key?
vk6zgo:
Is it a "real" car key, with a metal bit you put into the ignition & turn?
If so, you would be better off forgetting any "high tech" methods related to its RFID function, & just look for it with a metal detector.
They are usually sensitive enough to detect wedding rings & the like, so they should be able to pick up the key.
In a pinch, the copper on the PCB may be detectable.
Yansi:
--- Quote from: mikeselectricstuff on August 31, 2019, 10:00:20 am ---
--- Quote from: Psi on August 31, 2019, 05:51:19 am ---
I doubt the ECU is generating RF and sending it to keyswitch module. Since that would need shielded RF cable running ECU to Keyswitch module.
--- End quote ---
It's only 125KHz, barely RF. I've definitely seen schematics showing only the coil in the key/button assembly, don't know if they used shielded cable or not. Bear in mind these are only polled at startup, so it won't have noise from engine or other systems to contend with.
--- End quote ---
No they are not polled only at startup. Most of them not.
Yansi:
--- Quote from: vk6zgo on August 31, 2019, 10:04:39 am ---Is it a "real" car key, with a metal bit you put into the ignition & turn?
If so, you would be better off forgetting any "high tech" methods related to its RFID function, & just look for it with a metal detector.
They are usually sensitive enough to detect wedding rings & the like, so they should be able to pick up the key.
In a pinch, the copper on the PCB may be detectable.
--- End quote ---
Doubt a metal detector would pick a smidge of copper on the pcb. It should pickup the mechanical key though quite well.
langwadt:
--- Quote from: Yansi on August 31, 2019, 12:29:24 pm ---
--- Quote from: mikeselectricstuff on August 31, 2019, 10:00:20 am ---
--- Quote from: Psi on August 31, 2019, 05:51:19 am ---
I doubt the ECU is generating RF and sending it to keyswitch module. Since that would need shielded RF cable running ECU to Keyswitch module.
--- End quote ---
It's only 125KHz, barely RF. I've definitely seen schematics showing only the coil in the key/button assembly, don't know if they used shielded cable or not. Bear in mind these are only polled at startup, so it won't have noise from engine or other systems to contend with.
--- End quote ---
No they are not polled only at startup. Most of them not.
--- End quote ---
what would be the point of polling other than at startup? don't want the engine to shut driving down the road off just because
the communication with the key is sketchy
RoGeorge:
-trained dog
-thermal camera
-magnet dragged through the garden
-metal detector
-RFID reader
-buy another key
-buy another car
:)
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