In mid-2008 I designed with Philippe from /tmp/lab the “Consumer-B-Gone” mobile phone ringtone.
Named after the popular TV-B-Gone, it allows you to control the anti-theft in-wheel brakes designed by Gatekeeper Systems. You can lock and unlock the wheels at your will by playing the appropriate ringtone close to the cart !
When you play the ringtone, the electromagnetic interference caused by the coil inside the speaker of your mobile phone reproduces the signal transmitted by the Gatekeeper Systems antenna. A good demonstration of induction laws, a good example of security systems going wrong, and the perfect tool for scaring the consumers away on no-shopping events !
The French newspaper “Le Monde Diplomatique” has an article which speaks about the Consumer-B-Gone. Read it here, in French.