This project contains a PoC firmware for Nordic nRF51822 chips such as used by the BBC micro:bit. After flashing our firmware, the device sends out Bluetooth Low Energy advertisements such that it can be found by Apple's Find My network.
Note that the firmware is just a proof-of-concept and currently only implements advertising a single static key. This means that devices running this firmware are trackable by other devices in proximity.
You need to GNU Arm Embedded Toolchain to build the firmware. On macOS, you can install it via Homebrew:
brew install --cask gcc-arm-embeddedYou need to specify a public key in the firmware image. You can either directly do so in the source (public_key) or patch the string OFFLINEFINDINGPUBLICKEYHERE! in the final firmware image.
To build the firmware, it should suffice to run:
makefrom the main directory, which also takes care of downloading all dependencies. The deploy-ready image is then available at offline-finding/build/offline-finding.bin.
To deploy the image on a connected nRF device, you can run:
make install DEPLOY_PATH=/Volumes/MICROBITWe tested this procedure with the BBC micro:bit V1 only, but other nRF51822-based devices should work as well.
- Milan Stute (@schmittner, email, web)
This firmware is licensed under the MIT License.