Mark DominusFeb 21

“Most electronic shopping cart wheels listen for a 7.8 kHz signal from an underground wire to know when to lock and unlock. A management remote can send a different signal at 7.8 kHz to the wheel to unlock it. Since 7.8 kHz is in the audio range, you can use the parasitic EMF from your phone's speaker to ‘transmit’ a similar code by playing a crafted audio file.”

This sounds improbable but I needed to use it just now and it worked both times.

https://www.begaydocrime.com/

Hack this Shopping Cart

Show threadMartin Schobert
@mjd It reminds me of @henryk who used an ipod and a coil for signal replay of an LF transponder to open a door at a local university.
Feb 22 at 1:03pmWeb
Show threadHenryk PlötzFeb 22
@nitram2342 @mjd Haha, I thought of that too. IIRC back then it was a ~2kbit/s data signal with Manchester modulation -> 4kHz edge to edge, leading to a Nyquist frequency of ~8kHz, deep in the audio range. I put the wav file on my iPod, hooked up the tuned coil, hit play, and the door opened before I even realized that it was working.