How can I create an Android BLE peripheral?

Question

I try to make two bluetooth BLE apps:

• one central role
• one peripherall

But I have found some problem and my apps crashed.

This is the step which I followed:

1- client set the descriptor

BluetoothGattDescriptor descriptor = MeasurementCharacteristic.getDescriptor(
                UUID.fromString("00002902-0000-1000-8000-00805f9b34fb"));
        descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
        bluetoothGatt.writeDescriptor(descriptor); 

2 - The server in onDescriptorWriteRequest set the

MeasurementCharacteristic.setValue(test.getBytes());
gattserver.notifyCharacteristicChanged(device, MeasurementCharacteristic, false);

3 - The client receive this notification and I have done this :

CommandsCharacteristic.setValue(string_value.getBytes());
                write(CommandsCharacteristic);

4 - The server receives this in onCharacteristicWriteRequest and I have done this :

if(uuid.equals(CostantUUid.Commands))
            {
                .....
                engineMeasurementCharacteristic.setValue(test.getBytes());
                ble.getGattServer().notifyCharacteristicChanged(device, MeasurementCharacteristic, false);
            }

5- on the client the notifyCharacteristicChanged will be called and we will return to step 3

But sadly the comunication automatically shut down after few message.

• client enable descriptor
• server send notification to the client
• client read the new characteristic and re-write to server
• server resend notify to client
• client read send message to client
• the message doesn't arrive...

With the log I have seen that onCharacteristicWrite's function is been called only once in all the app life. Is been called after the message that it doesn't arrive with status 133 , but I don't understand why it not been called after the other messages.

@Override
                public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic,int status)
                {

                    super.onCharacteristicWrite(gatt, characteristic, status);

                    if(status==BluetoothGatt.GATT_SUCCESS)
                    {
                        Log.i("test","GATT SUCCESS");
                    }
                    if(status==BluetoothGatt.GATT_CONNECTION_CONGESTED)
                    {
                        Log.i("test","GATT WRITE connection congested");
                    }
                    if(status==BluetoothGatt.GATT_WRITE_NOT_PERMITTED)
                    {
                        Log.i("test","GATT WRITE not permitted");
                    }
                    if(status==BluetoothGatt.GATT_INVALID_ATTRIBUTE_LENGTH)
                    {
                        Log.i("test","GATT invalid attribute lenght");
                    }
                    if(status==BluetoothGatt.GATT_FAILURE)
                    {
                        Log.i("test","GATT WRITE other errors");
                    }
                    if(status==BluetoothGatt.GATT_CONNECTION_CONGESTED)
                    {
                        Log.i("test","GATT WRITE congested");
                    }
                    if(status==BluetoothGatt.GATT_INSUFFICIENT_AUTHENTICATION)
                    {
                        Log.i("test","GATT WRITE authentication");
                    }
                    else
                    {
                        Log.i("test","GATT WRITE :"+status);
                    }
                }

central role's log:

    03-30 15:09:22.308: W/BLE(30615): STATE_CONNECTED
*******
*******
03-30 15:09:50.958: D/HeadsetStateMachine(2312): Disconnected process message: 10
03-30 15:09:50.958: D/KeyguardUpdateMonitor(1026): received broadcast android.intent.action.BATTERY_CHANGED
03-30 15:09:50.958: D/KeyguardUpdateMonitor(1026): handleBatteryUpdate
03-30 15:09:50.958: D/BatteryService(795): level:64, scale:100, status:3, health:2, present:true, voltage: 3898, temperature: 283, technology: Li-ion, AC powered:false, USB powered:false, Wireless powered:false, icon:17303543, invalid charger:0, online:1, current avg:-242, charge type:0, power sharing:false
03-30 15:09:50.958: D/BatteryService(795): Sending ACTION_BATTERY_CHANGED.
03-30 15:09:50.958: D/STATUSBAR-PhoneStatusBar(1026):  mBrightnessEnablebySettings = true mBrightnessEnablebyBattery = true mBrightnessEnablebyDisableFlag = true mPmsBrightnessEnablebySettings = true
03-30 15:09:50.958: D/BatteryMeterView(1026): ACTION_BATTERY_CHANGED : level:64 status:3 health:2
03-30 15:09:50.968: D/STATUSBAR-IconMerger(1026): checkOverflow(2112), More:false, Req:false Child:2
03-30 15:09:52.978: D/SensorService(795):   0.0 -0.1 9.9
03-30 15:09:55.158: D/bt_vendor(2312): op for 7
03-30 15:09:55.158: D/bt_upio(2312): proc btwrite assertion
03-30 15:09:55.178: D/SSRMv2:SIOP(795): SIOP:: AP = 300, Delta = 0
03-30 15:09:55.188: E/bt-btm(2312): btm_sec_disconnected - Clearing Pending flag
03-30 15:09:55.188: D/IOP_DB_BT(2312): db_query_create: id DisablePwlCtrReq :: key KEY_BDADDR, value 4b:87:e8:45:76:b9
03-30 15:09:55.188: D/IOP_DB_BT(2312): db_query_add_key: key KEY_LMP_MFCT, value 0
03-30 15:09:55.188: D/IOP_DB_BT(2312): db_query_add_key: key KEY_LMP_VER, value 0:0
03-30 15:09:55.188: D/IOP_DB_BT(2312): db_query_add_key: key KEY_DIR_ALL, value *
03-30 15:09:55.188: D/IOP_DB_BT(2312): db_query_execute: result 1
03-30 15:09:55.188: D/BtGatt.btif(2312): btif_gattc_upstreams_evt: Event 4
03-30 15:09:55.188: D/BtGatt.GattService(2312): onWriteCharacteristic() - address=4B:87:E8:45:76:B9, status=133
03-30 15:09:55.188: D/BluetoothGatt(30615): onCharacteristicWrite() - Device=4B:87:E8:45:76:B9 UUID=687bf0f0-d6dc-11e4-b9d6-1681e6b88ec1 Status=133
03-30 15:09:55.188: D/BtGatt.btif(2312): btif_gattc_upstreams_evt: Event 5
03-30 15:09:55.188: D/BtGatt.GattService(2312): onDisconnected() - clientIf=6, connId=6, address=4B:87:E8:45:76:B9
03-30 15:09:55.188: D/BluetoothGatt(30615): onClientConnectionState() - status=0 clientIf=6 device=4B:87:E8:45:76:B9
03-30 15:09:55.188: I/*****(30615): status = 0 newState = 0
03-30 15:09:55.188: W/BLE(30615): STATE_DISCONNECTED

Peripheral log:

03-30 15:09:24.001: D/MyActivity(10354): onCharacteristicReadRequest requestId=3 offset=00002a24-0000-1000-8000-00805f9b34fb
03-30 15:09:24.003: D/BtGatt.btif(9706): btif_gatts_send_response
03-30 15:09:24.003: D/BtGatt.btif(9706): btgatts_handle_event: Event 2012
03-30 15:09:24.003: D/BtGatt.GattService(9706): onResponseSendCompleted() handle=46
03-30 15:09:24.096: D/BtGatt.btif(9706): btapp_gatts_handle_cback: Event 1
03-30 15:09:24.097: D/BtGatt.GattService(9706): onAttributeRead() UUID=00002a27-0000-1000-8000-00805f9b34fb, serverIf=5, type=2
03-30 15:09:24.097: D/MyActivity(10354): onCharacteristicReadRequest requestId=4 offset=00002a27-0000-1000-8000-00805f9b34fb
03-30 15:09:24.098: D/BtGatt.btif(9706): btif_gatts_send_response
03-30 15:09:24.098: D/BtGatt.btif(9706): btgatts_handle_event: Event 2012
03-30 15:09:24.098: D/BtGatt.GattService(9706): onResponseSendCompleted() handle=48
03-30 15:09:24.243: D/BtGatt.btif(9706): btapp_gatts_handle_cback: Event 2
03-30 15:09:24.243: D/BtGatt.GattService(9706): onAttributeWrite() UUID=00002902-0000-1000-8000-00805f9b34fb, serverIf=5, type=3
03-30 15:09:24.246: D/BtGatt.btif(9706): btif_gatts_send_response
03-30 15:09:24.246: D/BtGatt.btif(9706): btgatts_handle_event: Event 2012
03-30 15:09:24.246: D/BtGatt.GattService(9706): onResponseSendCompleted() handle=52
03-30 15:09:24.249: D/BtGatt.btif(9706): btif_gatts_send_indication
03-30 15:09:24.252: D/BtGatt.btif(9706): btgatts_handle_event: Event 2011
03-30 15:09:24.257: D/BtGatt.btif(9706): btapp_gatts_handle_cback: Event 5
03-30 15:09:24.257: D/BtGatt.GattService(9706): onNotificationSent() connId=5, status=0
03-30 15:09:24.341: D/BtGatt.btif(9706): btapp_gatts_handle_cback: Event 2
03-30 15:09:24.341: D/BtGatt.GattService(9706): onAttributeWrite() UUID=687bf0f0-d6dc-11e4-b9d6-1681e6b88ec1, serverIf=5, type=2
03-30 15:09:24.342: D/MyActivity(10354): onCharacteristicWriteRequest requestId=6 offset=687bf0f0-d6dc-11e4-b9d6-1681e6b88ec1
03-30 15:09:24.343: I/test(10354): Message received ciao 
03-30 15:09:24.344: D/BtGatt.btif(9706): btif_gatts_send_indication
03-30 15:09:24.345: D/BtGatt.btif(9706): btgatts_handle_event: Event 2011
03-30 15:09:24.345: D/BtGatt.btif(9706): btapp_gatts_handle_cback: Event 5
03-30 15:09:24.345: D/BtGatt.GattService(9706): onNotificationSent() connId=5, status=0
03-30 15:09:54.518: W/bt-btif(9706): bta_gattc_conn_cback() - cif=3 connected=0 conn_id=3 reason=0x0013
03-30 15:09:54.518: W/bt-btif(9706): bta_gattc_conn_cback() - cif=4 connected=0 conn_id=4 reason=0x0013
03-30 15:09:54.519: W/bt-btif(9706): bta_gattc_conn_cback() - cif=6 connected=0 conn_id=6 reason=0x0013
03-30 15:09:54.519: E/bt-btm(9706): btm_sec_disconnected - Clearing Pending flag
03-30 15:09:54.519: D/BtGatt.btif(9706): btapp_gatts_handle_cback: Event 15
03-30 15:09:54.519: D/BtGatt.GattService(9706): onConnected() connId=5, address=B8:6C:E8:5A:99:D2, connected=false
03-30 15:09:54.520: E/BluetoothRemoteDevices(9706): aclStateChangeCallback: Device is NULL
03-30 15:09:54.521: D/BluetoothGattServer(10354): onServerConnectionState() - status=0 serverIf=5 device=B8:6C:E8:5A:99:D2
03-30 15:09:54.522: D/MyActivity(10354): onConnectionStateChange status=0->0
03-30 15:09:59.001: E/WifiStateMachine(449): WifiStateMachine CMD_START_SCAN source -2 txSuccessRate=0.69 rxSuccessRate=23.35 targetRoamBSSID=any RSSI=-69
03-30 15:10:02.207: D/HeadsetStateMachine(9706): Disconnected process message: 10, size: 0
03-30 15:10:19.001: E/WifiStateMachine(449): WifiStateMachine CMD_START_SCAN source -2 txSuccessRate=0.78 rxSuccessRate=22.32 targetRoamBSSID=any RSSI=-68
03-30 15:10:38.999: E/WifiStateMachine(449): WifiStateMachine CMD_START_SCAN source -2 txSuccessRate=0.32 rxSuccessRate=34.32 targetRoamBSSID=any RSSI=-67

EDIT : I have cleaned the precedent message with the add of all of your suggestion/advice :)

EDIT 2 : The peripherall still alive, but disconnected. If I reconnect the connection restart, and redo the same step above :(

EDIT3 : on the peripherall I have setted in this way :

settingsBuilder.setAdvertiseMode(AdvertiseSettings.ADVERTISE_MODE_BALANCED);
    settingsBuilder.setTxPowerLevel(AdvertiseSettings.ADVERTISE_TX_POWER_HIGH);
    settingsBuilder.setConnectable(true);

EDIT5 : I solve my problem. There was an error inside OnCharacteristicWriteRequest inside peripherall. The app still working but the connection was crashing. :)

EDIT6 : How can retrieve the real MAC address of my peripherall ? Because on the client side when I use "getAddress()" the MAC address changes each time the peripherall reboots

Answer 1

Try out the official example at Bluetooth Low Energy . I've used this example and it works.

In this example, the Android app is the client, but you can have the Android app play the role of the GATT server as well. See BluetoothGattServer for more details.