Recently someone at a party told me thieves could detect a laptop in the car boot, even when turned off. At first I thought this was ridiculous, but I found some google queries provided a theory, the thieves used an inductive amplifier to detect the wires inside of a laptop.

I'm still a bit sceptical. Isn't the car full of wires anyway? Wouldn't the car's hull hide the laptop from the inductive amplifier?

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    One thing to be aware of, is even during power-down conditions there is usually a 3V coin cell on the motherboard powering the RTC. Also, there might be some current being drawn from the battery by its protection circuit. But compare this to the wide variety of other devices running in a car when it is stopped (clock/radio, alarm system, remote keyless entry... etc.) to a 3V battery running a clock at 32.768 kHz and a few mA from the battery? Not going to happen...
    – Thomas O
    Jul 13, 2011 at 22:17

2 Answers 2


Is it possible to detect a laptop inside of a car boot?

Generally speaking, having equipment like used for example by Customs and Border Protection, you can. I'm not sure though if that would be in common thieves' league.

[...] thieves used an inductive amplifier to detect the wires inside of a laptop.

No, that is not possible. Each of the reasons below is enough to make it impossible:

Now, it's very possible that car thieves have been caught with inductive amplifiers, as they would use them to detect car alarm wires.


I think the actual incidents that caused the media to get interested were based around bluetooth, rather than any more arcane techniques. Many people just put their laptops into standby, not full powerdown, and in this state, bluetooth may be enabled and running, in which case it can respond to probes - thus leading to a simple identification for attackers.

This story at the Telegraph has some high level info - I don't think there have been large numbers of attacks, but it is tricky to point the finger. You'd have to catch someone in the act of scanning for bluetooth, and you can do that without any kit other than a smartphone...

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    yah. Were similar stories here a few years ago about thieves going around scanning parked cars for active bluetooth devices, then breaking in to get at the (mainly) cellphones.
    – jwenting
    Jul 14, 2011 at 8:33
  • Here's a Risk Digest report on Blutooth laptop thefts at Disney World: catless.ncl.ac.uk/Risks/23.87.html#subj9 and a 2005 discussion on Schneier on Security: schneier.com/blog/archives/2005/08/bluetooth_as_a.html (Unfortunately link rot means that the primary source link is broken).
    – MZB
    Jul 15, 2011 at 1:15

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