My payment card was just a bit too wide to fit in my cellphone’s cover. The phone’s own NFC antenna is at the top - and I use it all the time - so the card had to be at the bottom of the cover to avoid triggering the phone all the time, in portrait orientation so-to-speak.
So I dissolved the card in acetone to extract the NFC chip and its antenna, then carefully reshaped one end of the antenna so it’s a bit less wide (and since I couldn’t modify the length of the wire or the number of turns in any way to avoid de-tuning the antenna too much, I sort of accordioned one side of the rectangle to accommodate the extra length of wire).
Then I set the new shape of the antenna permanently by carefully applying a piece of packing tape over it, flipped it over, taped over the other side to seal everything, then carefully cut around the new, ultra-thin, stubbier contactless payment “card”.
I dissolved the card in acetone to extract the NFC chip and its antenna,
Wouldn’t the acetone also dissolve the insulation around the antenna wire? So when it touches itself, it shorts itself out, and – electrically speaking – you only have one turn of thicker wire?
Wire that thin is usually insulated with an enamel coating. I’d guess it’s either unaffected by acetone, or just tougher to breakdown. Allow the card to dissolve, but remove and dry asap, don’t let it linger longer than necessary.
Well if it dissolved any insulation, it will not work, as the coil isnt even coiling. It is not a one big coil buy just two ends shorted(or as in the picture, a very small coil. Since this works i can only conclude coating does not dissolve in acetone
Amazing, I have never thought of that! I have always carried my card behind the phone, which is a bit too thick for my liking, but this is such a great idea, thanks for sharing!
I’ll do one better:
My payment card was just a bit too wide to fit in my cellphone’s cover. The phone’s own NFC antenna is at the top - and I use it all the time - so the card had to be at the bottom of the cover to avoid triggering the phone all the time, in portrait orientation so-to-speak.
So I dissolved the card in acetone to extract the NFC chip and its antenna, then carefully reshaped one end of the antenna so it’s a bit less wide (and since I couldn’t modify the length of the wire or the number of turns in any way to avoid de-tuning the antenna too much, I sort of accordioned one side of the rectangle to accommodate the extra length of wire).
Then I set the new shape of the antenna permanently by carefully applying a piece of packing tape over it, flipped it over, taped over the other side to seal everything, then carefully cut around the new, ultra-thin, stubbier contactless payment “card”.
Now it fits really smartly in my cellphone cover!
Next time someone calls me a maniac, I’ll show them this.
Definitely doesn’t live up to their username.
The fact it’s secured with a piece of sellotape is just *chef’s kiss*.
Peak Lemmy behaviour I love it
I just wanted to say your dad is definitely proud of you dude
You just had to 1-up everyone here…
Wouldn’t the acetone also dissolve the insulation around the antenna wire? So when it touches itself, it shorts itself out, and – electrically speaking – you only have one turn of thicker wire?
Wire that thin is usually insulated with an enamel coating. I’d guess it’s either unaffected by acetone, or just tougher to breakdown. Allow the card to dissolve, but remove and dry asap, don’t let it linger longer than necessary.
Veritasium demoed this a few weeks ago while discussing tap-to-pay security and a vulnerability with apple pay+visa.
Well if it dissolved any insulation, it will not work, as the coil isnt even coiling. It is not a one big coil buy just two ends shorted(or as in the picture, a very small coil. Since this works i can only conclude coating does not dissolve in acetone
Ty, great idea will try it
Amazing, I have never thought of that! I have always carried my card behind the phone, which is a bit too thick for my liking, but this is such a great idea, thanks for sharing!
I am surprised that no one sells cases designed for exactly this
Fairphone 6 has an add-on exactly for this.
Kudos for the effort. With that said, this would definitely raise some eyebrows if you have to return the card when getting a new one.
I’ve never had to do that… Just say you lost it.
Depends on how fussy the bank is, but yeah.