how to avoid automatic connection in Android while scanning for devices

[slo]

Dear all,

I have a project with a nRF51822 based on S110 and SDK10. Almost everything is running fine, but every time I scan for devices, either by calling BluetoothAdapter.startDiscovery() or by doing it manually from Android Bluetooth Settings my Phone connects to the nRF51822.

How can I avoid that? What did I do wrong?

I have tried different values for ble_gap_adv_params_t.type, but I am not able to connect at all if I do not use BLE_GAP_ADV_TYPE_ADV_IND.

Is there an option that I have missed to tell the other peer not to automatically connect, but that allows to connect on demand?

My current peer for testing is a Samsung Galaxy S5 running Android 5.0.2.

The Phone does not automatically connect if I use BluetoothAdapter.startLeScan() (I have not tried BluetoothLeScanner.startScan()), but in Android 6 there is bug and it requires location services to be enabled and that is very hard to explain to the customers. So I would prefer to use BluetoothAdapter.startDiscovery().

UPDATE:

As BluetoothAdapter.startDiscovery() seems to be working fine in Android 6, I will use BluetoothAdapter.startLeScan() on Android 4.x and Android 5.x and BluetoothAdapter.startDiscovery() on Android 6.x and later.

But I still would like to check wether I did something wrong in my nRF51 firmware or if this is a bug in Android 5.x or my Samsung version of Android 5.x?

[Aleksander Nowakowski]

I don't know how does the startDiscovery() method behaves. Perhaps it always connects on device found, don't know, never tried. For sure the startLeScan() method does not connect automatically and there is no option to enable such feature. There is, however, an option to connect using autoConnect=true (device.connectGatt(...)) and then a device will be connected automatically when Android discovers it. But calling gatt.close() on this device will disable it and further scans will not trigger connection (Android may scan itself from time to time to find such devices).

[Aleksander Nowakowski]

If you use Bluetoth Setting to scan it will always connect when you click on a device that was found and will try to bind and start using (in case of HID only).

[Jonathan Lin]

Dear All,

We've been suffering Unreliable Auto Connection for quite a while... "autoConnect" sometimes just doesn't work to get the device back to connection. Below is the failure message returned whenever the problem happened.

Any of you have ideas? Many thanks in advance!

Appear the message "L2CAP got BLE scanner conn_comp in bad state: 4" The device can't re-connect. Using gatt.connectGatt to connect with auto=true ...