OpenHaystack is a framework for creating custom tracking tags that leverage Apple's Find My network to locate personal Bluetooth devices without cellular coverage.
The tool solves the problem of tracking physical objects by reverse-engineering Apple's Find My network and enabling users to build their own tracking accessories. It works by having Bluetooth devices broadcast beacons that nearby iPhones discover and report back to Apple's servers with location data. The framework consists of a macOS application that displays the last reported location of tracked devices and firmware that enables Bluetooth devices to broadcast the necessary beacons for discovery by iPhones.
OpenHaystack suits developers and users who want to track personal items using existing Apple infrastructure without relying on commercial tracking products. It works with BBC micro:bit devices or any other Bluetooth-capable hardware that can run the provided firmware. The project is experimental and incomplete, with known limitations such as accessories broadcasting a fixed public key that makes them trackable by other devices in proximity. The tool requires macOS and is not affiliated with or endorsed by Apple.
The project emerged from reverse-engineering and security analysis work conducted at an academic lab, with the authors having published research on Apple's offline finding system and identified vulnerabilities in the original implementation. Development appears to acknowledge the experimental nature of the codebase, with documentation noting that code is untested and incomplete. The project includes both a macOS application component and firmware for Bluetooth devices, indicating active work across multiple technical domains.
