RFID Watch Band Holder

I was tired of always pulling my key card out of my pocket to go through four doors just to get to my workplace every morning. I can't easily embed a coil with a chip inside my watch, but I can put it on a wrist band.

This holder is designed for a tag with 15mm diameter and up to 0.8mm thickness. The holder itself attaches to 22mm wristband that is about 1.5mm thick. I'm using UltraFit Nylon Strap from Garmin. The important thing is that with such band or similar (loop or NATO) bands the holder doesn't have to be in contact with your skin. The tag itself is held by two lips.

You can use either 125kHz RFID or NFC (13.56MHz) tags. 15mm tags are usually the bottom limit but should still be usable with most readers up to 1-2 cm distance. My workplace uses 125kHz RFID system so these can be easily cloned without breaking any encryption. So I used T5577 chips that I copied using Proxmark 3 or Chameleon Ultra.

Printing Notes

This design is intended for printing in TPU. I printed various samples in 95A and 90A hardness from Sunlu, Eryone and Geeetech. With properly dried filament, prints should be strong and not breakable by hand. I personally like the softness of 90A but 95A is just as usable.

In case you use different tag or strap, just ping me and I'll try to do my best and update to include other sizes.