chris marc dailey (cmdwtf)
Odiin
Emulate NTAG21x-style NFC-A tags from files on an SD card to learn the nRF52840 NFC peripheral.
NFC emulationnRF52840Open hardwareDIY build
The maker publishes this as a project, not a product listing.
For access-control research and testing. Copying or emulating credentials you do not own is a crime in most countries. Buyers are responsible for their local law.
- Bring along
- A makerdiary Pitaya Go, the custom Biifröst bridge PCB, an ILI9341 LCD, a debug probe and the ARM build toolchain.
- Keep in mind
- It is an early, hand-assembled learning project: emulation is partial, assembly instructions are unfinished and it needs several off-the-shelf parts.
Image credit
Maker photo: the Odiin prototype showing its about screen on the LCD · chris marc dailey (cmdwtf)(02) Blueprint
Build it yourself
Full KiCad source for the custom 'Biifröst' bridge PCB plus 3D-printed case STLs are public; the rest of the build uses an off-the-shelf nRF52840 dev board.
bottom
Read straight from the maker’s repository. Open on GitHub
Design files 4
Source 2
git clone https://github.com/cmdwtf/Biifrost.gitResearch notes
cmdwtf/Odiin (0BSD) is the firmware+prototype repo; its .gitmodules pulls in cmdwtf/Biifrost, a standalone KiCad project for the bridge PCB (schematic + kicad_pcb + Gerbers-ready via OSH Park shared project link in the BOM). Main compute is a third-party Pitaya Go board (not Odiin's own design), so the MCU itself isn't 'open hardware' by this project — only the bridge board is.
Every link checked 2026-09-27.
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Specifications
Hardware
6
NFC emulation
4
No matching specification. Try a chip name, connector or feature.
What still needs checking
- Tag emulation is partial: it loads tags of a specific size only, and MIFARE and NDEF are not implemented.
- Assembly instructions are marked coming soon, and the bill of materials is described as in flux.
- Board dimensions, exact battery model and a standalone (non-prototype) PCB are not provided; the current build is hand-assembled from several parts.
