Detecting BLE Trackers

The speakers open with a scenario from a domestic violence consultation, where a person felt tracked even though no one was following her. That framing sets up the question of how hidden location tags can be found. They explain that Bluetooth Low Energy advertisements are broadcast continuously, unlike classic Bluetooth's hidden hopping pattern, so a listener can pick up tracker beacons and follow their channel hops. Manufacturer identifiers inside the advertisement data let a scanner tell Apple devices apart, including AirTags versus iBeacons and registered versus unregistered tags, and recognize other brands.

The main build is a cheap ESP32-based display board, costing roughly eleven dollars, programmed through the Arduino IDE. The code checks each advertisement payload for known manufacturer IDs and reports what it finds on the screen and over serial. Bluetooth SIG company identifiers can extend coverage to other trackers, and the same method could flag devices such as vehicles or medical wearables, which raises privacy concerns. The speakers note that recent Android releases added built-in AirTag detection, but argue that a dedicated device is simpler for many people to configure.

The talk closes candidly about the prototype's limits: the display shows only a handful of results, serial output does not always match the screen, and only a few tracker types are supported. The speakers invite contributions to the open project and mention alternative firmware such as Marauder and Bruce that run on the same hardware. The takeaway is that the parts are cheap and the tooling is approachable, so anyone can build a practical tracker detector.