Bluetooth pairing and assigning devices to users
How to fix devices that won't connect to the app, clear pairing bugs, and properly assign hardware in multi-user studies.
Symptom. The device shows in the phone's Bluetooth settings but the app will not connect; the blue LED disappears; the device is not found; or the device appears connected but no data flows; or you cannot assign the device to the right user in a multi-device study.
Fixes.
1. App version. Update to the current Hexoskin App. Older versions have known BLE pairing bugs.
2. Forget and re-pair properly. On the phone: Settings, Bluetooth, Forget the Hexoskin device; power cycle the device; re-pair from inside the app, not from the Android or iOS Bluetooth settings.
3. "Forget without Factory Reset" bug (App 6.0.0, confirmed February 2026). If you used "Forget this device" in the app without doing a Factory Reset first, the device stays in a connected-but-not-paired state and no data flows. Fix: Factory Reset via OneSync, then re-pair in the app from scratch.
4. Debug mode. Holding the device button for 2 seconds enters debug mode and blocks pairing. Update the firmware, which removes this behaviour, and power cycle.
5. Too many paired devices on the phone. Remove unused Bluetooth devices and retry.
6. New phone (Android). Install the app from the Play Store, log in with your existing account, do a Factory Reset via OneSync if the device was paired to a previous phone, then pair inside the app.
7. Assigning devices to users (studies). Assign each device to its user in the app or Dashboard before the first recording, and keep the S/N-to-participant list up to date. If recordings were made under the wrong user, contact support with the S/N and time range; recordings can be reassigned on the backend.