Board visible in bluetooth scan, can't connect until attempt connection with another device first.

I've been working on writing an app to download logged accelerometer data from my MMR board.

Occasionally I will encounter a situation where the board will not connect.

  • board is visible in bluetooth scanning mode
  • board has enough battery/is charging
  • previously connected to the board successfully
  • can't connect to the board with meta base app
  • Can't connect to board with Nordic Semiconductor bluetooth app

If I connect to a separate MetaWear board and disconnect, then try reconnecting to original MMR the connection is successful.

  1. What might be causing this? I'm guessing the board still thinks it's connected to the app or something
  2. How can I detect when this has happened and reestablish the connection without jumping to another board first?



  • To add more detail - one of the cases where this happens is when I initiate a long download and disconnect (phone restart or killing the app) before the download is complete.
    Turning bluetooth off and on again on my phone does not allow me to reconnect either. So far the only solution has been to connect to another device first.

  • I have also encountered this problem and it turned out that the device must be disconnected formally. You can try to disconnect the device by code (use the API not just restart the phone or kill the app).

  • Make sure to use the correct disconnect calls when using our APIs. It is likely that you are not using the right calls and disconnecting properly so you have to force a disconnect at the hardware level.

    To ensure a disconnect at the software levels, check out our APIs. Also check out the full_reset sequence:

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