Will you link to the exact product you have? The xEM is implantable and comes in an injector. They have a field detector that comes in a keychain, is that what you have?
OMG, so embarrassed. I thought that was the implant. I just realized the implant was pre-loaded into the injector. Sorry for the ignorance and garbage post.
I wanted to make a rewritable HID ProxKey II, and the xEM implant is the exact same size as the HID chip I removed from the fob. Here it is before I cover it with hot glue.
I would personally measure the cavity, and find the largest T5577 and Antenna that you can fit in there, It will make your life just a little easier when you are trying to read and write to it
That 15mm coil looks like the perfect match for a project I had not that long ago: I wanted to embed an RFID chip into existing alarm key fobs. However I’m likely going to move soon so that’s postponed for the time being.
I guess that’s the expensive way to do it… But you can always get that chip sterilized and implanted as long as you didn’t go too crazy with the hot glue.
If I were you, I’d order the 15mm chip that Pilgrimsmaster mentioned for the fob and I’d get the xEM autoclaved and implanted. But I do understand that implants are not for everyone.
If I do this again I’ll definitely try one of those bare coils, I didn’t even know such a thing existed (I’m such a newb in this space). It looks like I could have saved myself about $35 had I used a coil like that. Live and learn.
For me this project has been so fun. Learning about a tech space I previously knew less than zero about has been more exciting than anything else. What started as me looking at https://clonemykey.com/ as a way to copy a proxkey II keyfob ended in me learning about various chipsets, owning a Proxmark 3, disassembling a legit proxkey II and converting it into a programmable T5577 fob… and learning about the implant culture!