Have you ever looked into your Credit Card ?

No, I’m not trading as a ‘financial advisor’ … it’s a technical question.

Years ago, when Chip & Pin cards appeared, curiosity led me to dissect a few.

Yesterday, I realised that I had never checked inside a ‘contactless’ one … so my expired Capital One Visa card gave its body to science:

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The antenna loop is clearly visible, albeit damaged by my clumsy technique.

MichaelG.

Now leave it in acetone over a few hours - like they did on TV.

Haven’t watched much TV for a while

MichaelG.

On another thread I posted a link to the Hannah Fry documentaries - there was one on smartcards where she dissolved the card away just leaving the chip and "antenna" and she was still able to buy a coffee with it!

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… Not even Hannah Fry

In the early days of contactless-payment cards, a very bright light, shone through the card, allowed one to see the embedded conductor traces. The antenna loop, usually running around the card, near to its edge, could then be cut, to disable the contactless payment function. I used to do this, because of scare stories of folk losing their cards, only for some low-life to run up a stonking bill. My bank claimed that it could not turn off the functionality, however I believe that it's now possible. Later on, the cards became opaque to light, so I got a friendly mammographer to image a card. What surprised me was the complex network of conductor traces converging on the area for the signature. Does the act of signing make or break internal contacts, so the chip can detect a signature in some way? But why bother, since we're rarely asked to sign things these days? Anyone know? It all seems rather sneaky to me...

It's impressive engineering in its own right, making these things.

Having donated its body to science, the areas away from the electronics and embossing can then end up in the workshop shim-materials set...

It was an expired association-membership card that proved just right for non-magnetic feeler-gauges for setting my mill's DRO sensors.

Got a can of acetone will have to try it ! Noel.

I viewed the internals of a credit card using NIR illumination but can't find any photos. Here is an image of the chip and antenna from a disposable Dutch NFC train ticket. Illumination was from an 850nm LED and imaging using a compact digital camera with the IR filter removed and a visible block filter installed.

Edited By Andrew Entwistle on 29/05/2023 09:12:20

You can request non-radio bank cards. We do, to prevent people ripping off our accounts by carrying around radio card readers, and accessing our cards without our knowledge.