Contactless payment is a relatively new feature in debit cards that allows you to make payments for small purchases quickly and wirelessly over a short distance without having to enter your pin.
When my old debit card expired and a new one was sent, it came with this new feature. I wanted a way to disable it since each time I was scanning my RFID access card in my wallet, the detectors at work were picking up the debit card too. They'd beep twice and sometimes get confused. Not only this, but while my bank promises it's secure, I'd rather not have a feature I don't intend to use on the off-chance that it's not.
Existing articles I found when looking for a way to disable it guess at the location or infer it by cutting apart other contactless bank cards. Since I have access to a micro-CT scanner at the University of Huddersfield Centre for Precision Technologies, I thought I'd put my card in the machine, take a 2d xray still and allow myself to find the quickest and easiest way to disable it.
The above image is a a screen grab from the Xray preview of a Nikon micro-CT scanner. The low resolution is due to it being a live view image. When in operation the micro-CT scanner is capable of a resolution of several microns.
Step 1: How contactless payment works
Contactless payment works using RFID technology. A chip inside the card is powered when the card comes into close proximity to an RFID card reader. The signal emitted from the reader powers the chip though use of the embedded antenna. If this antenna is cut there will be no power to the chip and so when the card is held close to a reader the debit card won't reply.
By making cuts in the card where we know the antenna is, we can disable the wireless payment features.