Hey folks,
I know we talk about CoM conversions and custom implants a lot here, but I’m curious to see what others have done in regards to custom credential conversions into non-implantable form factors!
I’m gonna pop off with my adventures first just to get the ball rolling.
Personally, before I got my xNT I wore some of the cheapo aliex Ntag stickers under some nail polish just to see if I thought it was a worthwhile investment. I had looked at some of the NFC rings on the market but decided against them because most of the reputable ones appeared to only be readable when rotated into the correct orientation and frankly, I fidget too much. I ended up getting my xNT of course, but I still found myself thinking: Could I do better at home?
After some trial and error I made myself a really ghetto PLA ring frame, dissolved a cheap NTAG 216 card, wound the antenna around the ring body and epoxied the chip on and voila! A NFC ring readable from any orientation! it was pretty damn ugly and fat though, plus the PLA didn’t feel great on the skin so I decided to try out resin as my next material of choice. I figured while I was at it, I might as well try converting a different credential, so I tried a Presto (regional transit) card, which runs off of some kind of desfire if I’m not mistaken, and as far as my quick pokes around said, couldn’t be cloned.
For my 2nd ring, I decided I would use a mold for the inner ring frame, wrap the antenna, then pop that assembly into a 2nd frame and overmold it. That being said, I didn’t want to use TPU to make a mold due to part size, fragility, part geometry and being too cheap for mold release. I’ve seen how bad that can get when watching a friend of mine fight with vitaflex molded wheels in TPU so instead I chose to print my molds out of PVA filament, which most folks just use as a water soluable support for complex PLA and PETG prints. By simply dissolving the mold away from the ring I could negate any issues having to do with fragility, built in draft angles for removal, or mold release. I also found that I could cure UV activated resin through about 3mm of printed PVA which allowed as much working time as I wanted to chase out bubbles or top things up.(another advantage over TPU!!)
My second attempt yeilded some success, I did get my ring made and my phone could read it to load funds onto my account, but when I brought it to a reader at a train station… Nuthin. I tried taking the ring off and reading it parallel to the tap stand, perpendicular, on the presumed edge of the readed coil, but alas, no love. So I paid the old fashioned way that day and that was that. I haven’t looked at it since. Should probably give it a second shot sometime and see if adjusting the antenna somehow helps, but that’s for another time.
