我的BLE设备无法从Android接收数据

Question

I have a raspberry with the following characteristic (using Node.JS and Bleno library):

PrinterCharacteristic.prototype.onWriteRequest = function(data, offset, withoutResponse, callback) {
    this._value = data

    console.log('onWriteRequest working with "'+ this._value + '"')
}

Also, I have my Android device that should bind with that device and send data to it.

Here is my Android code:

BluetoothGatt mBluetoothGatt = device.connectGatt(getActivity(), false, new BluetoothGattCallback() {

    @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
        super.onConnectionStateChange(gatt, status, newState);

        if (status == BluetoothGatt.GATT_SUCCESS) {
            Log.d("BLE", "start discover");
            gatt.discoverServices();
        }
    }

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) {
        Log.d("BLE", "onServicesDiscovered");

        if (status == BluetoothGatt.GATT_SUCCESS) {
            BluetoothGattService mService = gatt.getServices().get(0);
            for (BluetoothGattCharacteristic bgc : mService.getCharacteristics()) {
                Log.d("BLE", "characteristic " + bgc.getUuid() + " " + bgc.toString());

                bgc.setValue("Hello World");

                Log.d("BLE", "writing characteristc");
                gatt.writeCharacteristic(bgc);
            }

        } else {
            Log.d("BLE", "onServicesDiscovered error");
        }
    }

});

Here is my Log:

09-16 13:03:46.769 18585-18585/us.inevent.apps.whiteLabel D/BluetoothGatt: connect() - device: B8:27:EB:98:BE:9D, auto: false
09-16 13:03:46.769 18585-18585/us.inevent.apps.whiteLabel D/BluetoothGatt: registerApp()
09-16 13:03:46.770 18585-18585/us.inevent.apps.whiteLabel D/BluetoothGatt: registerApp() - UUID=9a602983-99db-45fd-a3a3-2eb3ed72989a
09-16 13:03:46.772 18585-18987/us.inevent.apps.whiteLabel D/BluetoothGatt: onClientRegistered() - status=0 clientIf=6
09-16 13:03:47.192 18585-18602/us.inevent.apps.whiteLabel D/BluetoothGatt: onClientConnectionState() - status=0 clientIf=6 device=B8:27:EB:98:BE:9D
09-16 13:03:47.193 18585-18602/us.inevent.apps.whiteLabel D/BLE: start discover
09-16 13:03:47.193 18585-18602/us.inevent.apps.whiteLabel D/BluetoothGatt: discoverServices() - device: B8:27:EB:98:BE:9D
09-16 13:03:47.249 18585-18601/us.inevent.apps.whiteLabel D/BluetoothGatt: onSearchComplete() = Device=B8:27:EB:98:BE:9D Status=0
09-16 13:03:47.249 18585-18601/us.inevent.apps.whiteLabel D/BLE: onServicesDiscovered
09-16 13:03:47.250 18585-18601/us.inevent.apps.whiteLabel D/BLE: characteristic 00002a00-0000-1000-8000-00805f9b34fb android.bluetooth.BluetoothGattCharacteristic@1b258afb
09-16 13:03:47.250 18585-18601/us.inevent.apps.whiteLabel D/BLE: writing characteristc
09-16 13:03:47.250 18585-18601/us.inevent.apps.whiteLabel D/BLE: characteristic 00002a01-0000-1000-8000-00805f9b34fb android.bluetooth.BluetoothGattCharacteristic@3876d718
09-16 13:03:47.250 18585-18601/us.inevent.apps.whiteLabel D/BLE: writing characteristc
09-16 13:03:47.533 18585-18585/us.inevent.apps.whiteLabel D/BluetoothAdapter: stopLeScan()

It found two characteristics (as expected, WRITE and NOTIFY), and tried to send data to each of them, but my raspberry does not receive any data.

If I use the nRF Connect app, it works as expected.

What am I doing wrong? I'm not sure I understood exactly how BLE works.

Thanks.

Answer 1

It seems that Bleno has another service running. To solve my problem I've just searched for all characteristics inside all service and determined which one I should use by the UUID.