OpenHaystack is a framework for tracking personal Bluetooth devices via Apple's massive Find My network. Use it to create your own tracking tags that you can append to physical objects (keyrings, backpacks, ...) or integrate it into other Bluetooth-capable devices such as notebooks.

OpenHaystack is an application that allows you to create your own accessories that are tracked by Apple's Find My network. All you need is a Mac and a BBC micro:bit or any other Bluetooth-capable device. By using the app, you can track your accessories anywhere on earth without cellular coverage. Nearby iPhones will discover your accessories and upload their location to Apple's servers when they have a network connection.