Keep the phone at roughly a 30 cm distance from the car door while attempting to interact with the vehicle. This small distance can influence how signals are perceived and transmitted by devices placed near the lock area.
There has been talk about the possibility of opening a car with such a setup. It sounds unlikely, yet the idea persists because people often hope for a quick solution in tense moments, even when the odds seem slim.
To validate the claim, an expert was asked to test the advice in a controlled scenario and share what actually happens when the procedure is attempted.
Expert answer
Alexey Revin, known for reviewing automotive tech on the program Behind the Wheel, provided the assessment.
The core concept involves using a smartphone as a portable microphone and transmitter. In certain conditions, a device can act as a relay, capturing air vibrations and routing them to another endpoint. However, the frequency range commonly transmitted by a typical smartphone is fairly narrow, usually in the ballpark of 300-8000 Hz, and that range is not enough to bridge all the gaps between a nearby phone and a locked car in most real-world environments.
So, the question remains: why would even a sound or signal be necessary when the key’s unlock button is pressed? If the phone sits close to the car, but the key is not within its effective signal range, there is often no meaningful data exchange to initiate unlocking. In many cases, there would simply be nothing to transmit or receive at the doorstep of a locked vehicle, which means the car would not respond to the attempt.
To test the phenomenon, a demonstration was conducted on a neighbor’s porch. The tester stood by the window, talked into the phone, and pressed the unlock button on the key. With the tester near a locked car, the door unexpectedly opened. This surprising outcome led to deeper considerations: the signal range can extend beyond what is observed at the building entrance, especially when there are no interfering objects like parked cars or walls blocking the path. In such a setup, the key’s signal can reach the car more effectively than anticipated, creating the impression that the car unlocks through some unintended interaction.
With a second key in hand and the car moved to a nearby yard, the tester continued the conversation by phone. In that adjusted arrangement, the door locks would not respond—neither opening nor closing—confirming that the effect depends on the precise placement of keys and the surrounding environment.
Our verdict (and advice)
The initial claim does not hold under normal circumstances, but it is not something to dismiss outright. The practical takeaway is practical rather than dramatic: if a driver handles the car alone, it is wise to keep the second key somewhere other than the immediate pocket or hand, such as a different pocket or a bag. This simple precaution minimizes the risk if the first key’s battery drains or that battery becomes less responsive due to cold weather, which is a common issue in winter conditions.
A visual reference is available in the accompanying Depositphotos image.
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