My sensor will not connect

1. Is it in sync mode?

The app can only find the sensor while its light pulses blue. Short press the button until it does. From off, that takes two presses: the first switches it on and starts a recording (blinking red), the second switches it to sync mode (pulsing blue). If nobody connects within a few minutes, sync mode times out and the light goes dark, so press again. If nothing happens at all, charge it for twenty minutes first.

2. Check permissions

The app needs both Bluetooth and location permission. On Android, Bluetooth scanning returns nothing without location permission granted, so the sensor simply never appears and no error explains why. Check both in your phone's settings for the SANDIT app.

3. Do not pair from phone settings

Pair from inside the SANDIT app only. If you previously paired the sensor in your iOS or Android Bluetooth settings, remove it there. That stale pairing can hold the connection and block the app from getting it.

4. Restart both

Force-close the app. Hold the sensor's button until the light goes out to shut it down, then short press until the light pulses blue again. Reopen the app.

5. Get close

Within a metre, with no wetsuit or bag in between. A wet neoprene layer over the sensor cuts Bluetooth range noticeably.