> Key fobs are constantly broadcasting a signal that communicates with a specific vehicle, he said, and when it comes into a close enough range, the vehicle will open and start. Why is it transmitting without the user pressing a button? Is that a feature? As you walk up to the car it automatically starts like magic? I'm not familiar with these newer cars.
Yes, it’s a feature, so you don’t have to remove the key from a bag or pocket to enter or start the car. In typical designs, the car continually transmits a low-frequency (e.g., 135 kHz) radio signal to wake up any wireless keys within range. When a key receives this signal, it replies with a VHF (e.g., 315 MHz) signal, and the car unlocks or starts when a door is opened or the start button is pressed. The reply sign…
Could you just record the relay signal and play it back whenever, essentially replicating the key?