Bluetooth Low Energy Connection Parameters for Android, iOS and Win8

Question

I\'ve been looking all over the place for the required bluetooth connection parameters that will work for all three of these operating platforms. I\'m using the HOGP (Bluet

Answer 1

To modify parameters in Android (requesting from Central to Peripheral) you can do something like this:

private String CONN_SERVICE_UUID = "00001800-0000-1000-8000-00805f9b34fb";
private static final UUID CONN_CHARACTERISTIC_UUID = UUID.fromString("00002a04-0000-1000-8000-00805F9B34FB");
private static final int CONN_INTERVAL = 0x0006;
private static final int SUPERVISION_TIMEOUT = 0x000A;
private void findServiceForConnectionParams(List gattServices){
    BluetoothGattService connGattService = filterServices(gattServices, CONN_SERVICE_UUID);
    if (connGattService != null) {
        setConnectionInterval(connGattService);
    }
}
private void setConnectionInterval(BluetoothGattService gattService) {
    if (gattService == null) {
        Log.e(TAG, "setConnectionInterval. Gatt service is null!");
        return;
    }
    BluetoothGattCharacteristic connCharacteristic = 
            gattService.getCharacteristic(CONN_CHARACTERISTIC_UUID);
    if (connCharacteristic != null) {
        byte[] value = { (byte) (CONN_INTERVAL & 0x00FF), // gets LSB of 2 byte value
                (byte) ((CONN_INTERVAL & 0xFF00) >> 8), // gets MSB of 2 byte value
                (byte) (CONN_INTERVAL & 0x00FF),
                (byte) ((CONN_INTERVAL & 0xFF00) >> 8),
                0, 0,
                (byte) (SUPERVISION_TIMEOUT & 0x00FF),
                (byte) ((SUPERVISION_TIMEOUT & 0xFF00) >> 8)
        };
        connCharacteristic.setValue(value);
        boolean status = mBluetoothGatt.writeCharacteristic(connCharacteristic);
        Log.d(TAG, "setConnectionInterval. Change connection interval result: " + status);
    } else {
        Log.e(TAG, "setConnectionInterval. Connection characteristic is null!");
    }

}
private BluetoothGattService filterServices(List gattServices, String targetUuid) {
    for(BluetoothGattService gattService : gattServices){
        String serviceUUID = gattService.getUuid().toString();
        Log.i(TAG, "serviceUUID: " + serviceUUID);

        if(serviceUUID.equals(targetUuid)){
            Log.i(TAG, "serviceUUID matches! UUID: " + serviceUUID + " Type: " + gattService.getType());
            // no needed, just to check which characteristics are offered
            for(BluetoothGattCharacteristic characteristic : gattService.getCharacteristics()) {
                Log.i(TAG, "serviceUUID characteristics: " + characteristic.getUuid().toString());
            }
            return gattService;
        }
    }
    return null;
}

I must say though that it didn't work for me using Android 5 devices both as peripheral and central, because Generic Acces Service (0x1800) is not offering in my device Characteristic 0x2a04 for Preferred Connection Parameters. It's only offering 0x2a00 (device name) and 0x2a01 (appearance). References:

http://www.cumulations.com/blogs/7/Doing-firmware-upgrade-over-BLE-in-Android

https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.gap.peripheral_preferred_connection_parameters.xml

https://developer.bluetooth.org/gatt/services/Pages/ServiceViewer.aspx?u=org.bluetooth.service.generic_access.xml

https://farwestab.wordpress.com/2011/02/05/some-tips-on-android-and-bluetooth/