Step 1: Trackers shout, scanners listen
Lost-item trackers such as AirTag, SmartTag, Tile and Chipolo send tiny Bluetooth Low Energy messages every few seconds. A detector app listens to those messages and keeps only the ones that come from tracker-type devices. Headphones, watches and TVs are ignored.
Step 2: Identifiers change on purpose
To stop strangers following a tag passively, these devices change their identity from time to time. Detectors therefore look at the content of the broadcast as well, and link sightings made within the window in which the identity stays the same.
Step 3: Time and place decide, not presence
Seeing a tracker once means very little: the person next to you on a bus may carry one. What matters is whether a device stays with you after you have moved. TrackerGuard records each sighting with your approximate position and rates it:
- Following you: seen over 30+ minutes, in at least 5 sightings, at 3 or more places at least 150 metres apart (all adjustable).
- Watch: seen several times but without enough proof yet.
- Low or Nearby: heard briefly, usually a passer-by.
Without location access, TrackerGuard can only reach Watch, because it cannot tell a tracker that follows you from one that sits at the next desk.
Why phone alerts can take a while
Built-in alerts also want evidence before they warn you, in order to avoid false alarms. That is why an unknown tracker can travel with you for some time before a warning appears, and why a second tool such as TrackerGuard or AirGuard is a sensible extra check.
The limits of a web page
A web page can scan only while it is open and the screen is on, and it needs Chrome. Phone operating systems and native apps can scan in the background. TrackerGuard is designed to complement them, not replace them. See AirTag detector for Android for the options.
In testing. We are still tuning the thresholds with real-world feedback.