The situation goes a little something like this:

1. I am programming Xcode whilst concurrently listening to music on my Bluetooth headphones... you know to block out the world.

2. Then, I go to launch my app in the iOS simulator and BOOM all of a sudden my crystal clear music becomes garbled and super low quality like it is playing in a bathtub 2 blocks away... in the 1940s. 

3. Note: the quality deterioration does NOT occur if I am playing music on my laptop or cinema display and I launch the sim. It seems to be exclusively a Sim -&gt; Bluetooth issue. 

The problem is more than just annoying. Because often after stopping the simulator the crappy bathtub quality music continues. To fix it I have to open sound preferences in OSX and briefly toggle back to my laptop sound and then back to my Bluetooth headphones. 

This is a big deal because I launch the simulator 50x a day and have to do this toggle thing every time as well as suffer listening to 40s era mono ham radio quality music. 

For your information, the headphones I am using are Plantronics BackBeat Pro and I am up to date on firmware. I am on OSX 10.11.4 and Xcode 7.3... but this problem has persisted through all versions for 2+ years now. Can you save me from the 1940s?


Bluetooth headphone music quality deteriorates when launching iOS simulator

I am currently developing an application that will use Bluetooth Low Energy (testing on the Nexus 4). After getting started with the official BLE APIs in Android 4.3, I have noticed that after I connect a device for the first time I am rarely able to successfully connect to / communicate with that device or any other device again.

Following the guide [here](http://developer.android.com/guide/topics/connectivity/bluetooth-le.html), I can successfully connect to a device, scan services and characteristics, and read/write/receive notifications without any issues. However, after disconnecting and re-connecting, I am often unable to either scan services/characteristics or unable to complete a read/write. I can&#39;t find anything in the logs to indicate why this is happening.

Once this happens I have to uninstall the application, disable Bluetooth, and restart the phone before it will start working again.

Whenever a device is disconnected I make sure to call close() on the BluetoothGatt object and set it to null. Any insights?

---------
EDIT:&lt;br&gt;
Log dumps: For these logs I rooted my phone and upped the trace levels of related items in /etc/bluetooth/bt_stack.conf

[Successful connection][1] - First attempt after rebooting the phone and installing the app. I am able to connect, discover all services/characteristics, and read/write.

[Failed Attempt 1][2] - This is the next attempt after disconnecting from the successful connection above. It seems I was able to discover characteristics, but the first attempt to read returned a null value and disconnected soon thereafter.

[Failed Attempt 2][3] - An example where I am not even able to discover services/characteristics.

---------
EDIT 2:&lt;br&gt;
The device to which I am trying to connect is based on TI&#39;s CC2541 chip. I obtained a [TI SensorTag][4] (also based on the CC2541) to play around with and discovered that TI released [an android app][5] for the SensorTag yesterday. However, this app has &lt;b&gt;the same problem.&lt;/b&gt; I tested this on two other Nexus 4s with the same result: Connection to the SensorTag is successful the first or second time, but (according to the logs) fails to discover services thereafter, causing all sorts of crashes. I&#39;m starting to wonder if it&#39;s an issue with this specific chip?


  [1]: http://pastebin.com/wWrqsywZ
  [2]: http://pastebin.com/AhZq17bU
  [3]: http://pastebin.com/w0XjwDMW
  [4]: http://www.ti.com/ww/en/wireless_connectivity/sensortag/index.shtml?DCMP=sensortag&amp;HQS=sensortag-bn
  [5]: http://www.ti.com/tool/sensortag-sw?DCMP=lprf-stdroid&amp;HQS=sensortag-app-android

Android 4.3 Bluetooth Low Energy unstable

I&#39;d like to create my own iBeacon with some Bluetooth Low Energy dev kits. Apple has yet to release a specification for iBeacons, however, a few hardware developers have reverse Engineered the iBeacon from the AirLocate Sample code and started selling iBeacon dev kits. 

**So what is the iBeacon Bluetooth Profile?**

Bluetooth Low Energy uses GATT for LE profile service discovery. So I think we need to know the Attribute Handle, Attribute Type, Attribute Value, and maybe the Attribute Permissions of the iBeacon attribute. So for an iBeacon with a UUID of E2C56DB5-DFFB-48D2-B060-D0F5A71096E0, a major value of 1 and a minor value of 1 what would the Bluetooth GATT profile service be?

Here are some assumptions I&#39;ve made from the discussion on Apple&#39;s forums and through the docs.

1. You only need to see the profile service (GATT) of a Bluetooth peripheral to know it is an iBeacon.

2. The Major and Minor keys are encoded somewhere in this profile service


Heres some companies with iBeacon Dev Kits that seem to have this figure out already:

 - http://redbearlab.com/ibeacon/
 - http://kontakt.io/

  [1]: https://developer.apple.com/library/ios/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts/BestPracticesForSettingUpYourIOSDeviceAsAPeripheral/BestPracticesForSettingUpYourIOSDeviceAsAPeripheral.html

Hopefully, in time we will have a profile posted on Bluetooth.org like these: https://www.bluetooth.org/en-us/specification/adopted-specifications

What is the iBeacon Bluetooth Profile

Trying to grasp a basic concept of how distancing with ibeacon (beacon/ Bluetooth-lowenergy/BLE) can work. Is there any true documentation on how far exactly an ibeacon can measure. Lets say I am 300 feet away...is it possible for an ibeacon to detect this?

Specifically for v4 &amp;. v5 and with iOS but generally any BLE device.

How does Bluetooth frequency &amp; throughput affect this? Can beacon devices enhance or restrict the distance / improve upon underlying BLE? 

ie

                   | Range	     | Freq       | T/sec      | Topo       |      
                   |–—–––––––––––|–—––––––––––|–—––––––––––|–—––––––––––|
    Bluetooth v2.1 | Up to 100 m | &lt; 2.481ghz | &lt; 2.1mbit  | scatternet |
                   |-------------|------------|------------|------------|
    Bluetooth v4   |     ?       | &lt; 2.481ghz | &lt; 305kbit  | mesh       |
                   |-------------|------------|------------|------------|
    Bluetooth v5   |     ?       | &lt; 2.481ghz | &lt; 1306kbit | mesh       |



Understanding ibeacon distancing

After upgrading to Android version 6.0 Bluetooth Low Energy (BLE) scanning will only work if Location services are enabled on the device. See here for reference: https://stackoverflow.com/questions/33043582/bluetooth-low-energy-startscan-on-android-6-0-does-not-find-devices/33045489#33045489

Basically, you need to have the permission enabled for the app as well as on for the phone.  Is this a bug? Is it possible to scan without location services actually enabled? I don&#39;t want to have to have location for all my apps. 

**EDIT** 
I failed to mention that I am using the `startScan()` method in `BluetoothLeScanner` provided in API 21. I am okay with the course and fine location permissions in the manifest that this method require. I just don&#39;t want the users of my app to have to enable location services on their device (GPS, etc.) to use my app. 

Previously, the `startScan()` method would run and return results with the Location services disabled on the phone. On Marshmallow, however, the same application would &quot;scan&quot; but silently failed and returned no results when location services were not enabled on the phone and course/fine location permissions were still in the manifest.

Location needs to be enabled for Bluetooth Low Energy Scanning on Android 6.0

I want to enable/disable bluetooth through the program. I have the following code.

    BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();    
    if (!mBluetoothAdapter.isEnabled()) {
		    Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
		    startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
	

But this code is not working in SDK 1.5. How can I make it work?

	



How to enable/disable bluetooth programmatically in android

Currently I am trying to deal with a strange Exception when opening a BluetoothSocket on my Nexus 7 (2012), with Android 4.3 (Build JWR66Y, I guess the second 4.3 update). I have seen some related postings (e.g. [https://stackoverflow.com/questions/13648373/bluetoothsocket-connect-throwing-exception-read-failed][1]), but none seems to provide a workaround for this issue. Also, as suggested in these threads, re-pairing does not help, and constantly trying to connect (through a stupid loop) also has no effect.

I am dealing with an embedded device (a noname OBD-II car adapter, similar to [http://images04.olx.com/ui/15/53/76/1316534072_254254776_2-OBD-II-BLUTOOTH-ADAPTERSCLEAR-CHECK-ENGINE-LIGHTS-WITH-YOUR-PHONE-Oceanside.jpg][2]). My Android 2.3.7 phone does not have any issues connecting, and the Xperia of a colleague (Android 4.1.2) also works. Another Google Nexus (I dont know if &#39;One&#39; or &#39;S&#39;, but not &#39;4&#39;) also fails with Android 4.3.

Here is the Snippet of the connection establishment. It is running in its own Thread, created within a Service.

    private class ConnectThread extends Thread {
        
        private static final UUID EMBEDDED_BOARD_SPP = UUID
			.fromString(&quot;00001101-0000-1000-8000-00805F9B34FB&quot;);
        
		private BluetoothAdapter adapter;
		private boolean secure;
		private BluetoothDevice device;
		private List&lt;UUID&gt; uuidCandidates;
		private int candidate;
		protected boolean started;

        public ConnectThread(BluetoothDevice device, boolean secure) {
        	logger.info(&quot;initiliasing connection to device &quot;+device.getName() +&quot; / &quot;+ device.getAddress());
        	adapter = BluetoothAdapter.getDefaultAdapter();
            this.secure = secure;
            this.device = device;

            setName(&quot;BluetoothConnectThread&quot;);
            
            if (!startQueryingForUUIDs()) {
            	this.uuidCandidates = Collections.singletonList(EMBEDDED_BOARD_SPP);
            	this.start();
            } else{
            	logger.info(&quot;Using UUID discovery mechanism.&quot;);
            }
            /*
             * it will start upon the broadcast receive otherwise
             */
        }
        
    	private boolean startQueryingForUUIDs() {
			Class&lt;?&gt; cl = BluetoothDevice.class;
			
			Class&lt;?&gt;[] par = {};
			Method fetchUuidsWithSdpMethod;
			try {
				fetchUuidsWithSdpMethod = cl.getMethod(&quot;fetchUuidsWithSdp&quot;, par);
			} catch (NoSuchMethodException e) {
				logger.warn(e.getMessage());
				return false;
			}
			
			Object[] args = {};
			try {
				BroadcastReceiver receiver = new BroadcastReceiver() {
				    @Override
				    public void onReceive(Context context, Intent intent) {
				        BluetoothDevice deviceExtra = intent.getParcelableExtra(&quot;android.bluetooth.device.extra.DEVICE&quot;);
				        Parcelable[] uuidExtra = intent.getParcelableArrayExtra(&quot;android.bluetooth.device.extra.UUID&quot;);
				        
				        uuidCandidates = new ArrayList&lt;UUID&gt;();
				        for (Parcelable uuid : uuidExtra) {
				        	uuidCandidates.add(UUID.fromString(uuid.toString()));
						}

				        synchronized (ConnectThread.this) {
				        	if (!ConnectThread.this.started) {
				        		ConnectThread.this.start();
				        		ConnectThread.this.started = true;
				        		unregisterReceiver(this);
				        	}
				        	
				        }
				    }

				};
				registerReceiver(receiver, new IntentFilter(&quot;android.bleutooth.device.action.UUID&quot;));
				registerReceiver(receiver, new IntentFilter(&quot;android.bluetooth.device.action.UUID&quot;));
				
				fetchUuidsWithSdpMethod.invoke(device, args);
			} catch (IllegalArgumentException e) {
				logger.warn(e.getMessage());
				return false;
			} catch (IllegalAccessException e) {
				logger.warn(e.getMessage());
				return false;
			} catch (InvocationTargetException e) {
				logger.warn(e.getMessage());
				return false;
			}			
			
			return true;
		}

		public void run() {
			boolean success = false;
			while (selectSocket()) {
            
	            if (bluetoothSocket == null) {
	            	logger.warn(&quot;Socket is null! Cancelling!&quot;);
	            	deviceDisconnected();
	                openTroubleshootingActivity(TroubleshootingActivity.BLUETOOTH_EXCEPTION);
	            }
	            
	            // Always cancel discovery because it will slow down a connection
	            adapter.cancelDiscovery();
	
	            // Make a connection to the BluetoothSocket
	            try {
					// This is a blocking call and will only return on a
	                // successful connection or an exception
            		bluetoothSocket.connect();
            		success = true;
	            	break;
		            		
	            } catch (IOException e) {
	                // Close the socket
	                try {
	                	shutdownSocket();
	                } catch (IOException e2) {
	                    logger.warn(e2.getMessage(), e2);
	                }
	            }
        	}
			
			if (success) {
				deviceConnected();
			} else {
				deviceDisconnected();
                openTroubleshootingActivity(TroubleshootingActivity.BLUETOOTH_EXCEPTION);
			}
        }

		private boolean selectSocket() {
			if (candidate &gt;= uuidCandidates.size()) {
				return false;
			}
			
			BluetoothSocket tmp;
			UUID uuid = uuidCandidates.get(candidate++);
			logger.info(&quot;Attempting to connect to SDP &quot;+ uuid);
			try {
                if (secure) {
                    tmp = device.createRfcommSocketToServiceRecord(
                            uuid);
                } else {
                    tmp = device.createInsecureRfcommSocketToServiceRecord(
                    		uuid);
                }
                bluetoothSocket = tmp;
                return true;
            } catch (IOException e) {
            	logger.warn(e.getMessage() ,e);
            }
			
			return false;
		}

    }

The code is failing at `bluetoothSocket.connect()`. I am getting a `java.io.IOException: read failed, socket might closed, read ret: -1`. This is the corresponding source at GitHub: [https://github.com/android/platform_frameworks_base/blob/android-4.3_r2/core/java/android/bluetooth/BluetoothSocket.java#L504][3]
Its called through readInt(), called from [https://github.com/android/platform_frameworks_base/blob/android-4.3_r2/core/java/android/bluetooth/BluetoothSocket.java#L319][4]

Some metadata dump of the used socket resulted in the following information. These are exactly the same on Nexus 7 and my 2.3.7 phone.

    Bluetooth Device &#39;OBDII&#39;
    Address: 11:22:33:DD:EE:FF
    Bond state: 12 (bonded)
    Type: 1
    Class major version: 7936
    Class minor version: 7936
    Class Contents: 0
    Contents: 0

I have some other OBD-II adapters (more expansives) and they all work. Is there any chance, that I am missing something or might this be a bug in Android?


  [1]: https://stackoverflow.com/questions/13648373/bluetoothsocket-connect-throwing-exception-read-failed &quot;another SO questionquot;&quot;
  [2]: http://images04.olx.com/ui/15/53/76/1316534072_254254776_2-OBD-II-BLUTOOTH-ADAPTERSCLEAR-CHECK-ENGINE-LIGHTS-WITH-YOUR-PHONE-Oceanside.jpg &quot;these&quot;
  [3]: https://github.com/android/platform_frameworks_base/blob/android-4.3_r2/core/java/android/bluetooth/BluetoothSocket.java#L504 &quot;BluetoothSocket.java#L504&quot;
  [4]: https://github.com/android/platform_frameworks_base/blob/android-4.3_r2/core/java/android/bluetooth/BluetoothSocket.java#L319 &quot;BluetoothSocket.java#L319&quot;

IOException: read failed, socket might closed - Bluetooth on Android 4.3

How can I check the battery level of a connected bluetooth device? The device shows the battery level on Android so I&#39;m assuming the device supports the [GATT-based Battery Service][1]. However, by entering &quot;menu gatt&quot; in bluetoothctl and then listing the GATT attributes of the device with &quot;list-attributes [dev]&quot;, nothing shows up.

A [similar question was posted to SO][2] but the OP seems to have found a solution that doesn&#39;t work for me. When I run &quot;info [dev]&quot; in bluetoothctl I don&#39;t see the UUID for Battery Service.

I would prefer a solution that runs on the command line and is distro-agnostic.

Please let me know if this question should be posted on SuperUser instead.


  [1]: https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.service.battery_service.xml
  [2]: https://stackoverflow.com/questions/48058357/how-to-check-battery-level-of-a-bluetooth-paired-remote &quot;How to check battery level of a bluetooth paired remote&quot;

Check battery level of connected bluetooth device on linux

I don&#39;t understand what a bluetooth UUID denotes. Do UUIDs denote protocols (e.g. [RFCOMM][1])? If so, why do the `createRfcommSocketToServiceRecord()` methods require UUIDs, when they specify rfcomm right in their names? Why does the BluetoothChat sample code have a seemingly arbitrary, hardcoded UUID?

My question arises because, as per [this question][2], I&#39;m getting a null pointer exception when devices running 4.0.4 try to connect (to an external, non-android device) using reflection. However, the solution to that question doesn&#39;t work for me. `UUID muuid = device.getUuids()[0].getUuid();` raises an exception. 

**Edit**: I&#39;ve solved that problem by hardcoding the UUID for Serial port service as per [this answer][3] (using `UUID.fromString(&quot;00001101-0000-1000-8000-00805f9b34fb&quot;);`).

I&#39;m further puzzled by why I need to supply a UUID to create an unsecured rfcomm socket using `createInsecureRfcommSocketToServiceRecord(),` but not using the reflection method. 

Can anyone straighten me out?


  [1]: http://www.bluecove.org/bluecove/apidocs/javax/bluetooth/UUID.html
  [2]: https://stackoverflow.com/questions/12485785/nullptr-exception-on-socket-connect-galaxy-tab-2-running-android-4-04
  [3]: https://stackoverflow.com/a/11622794/1286571

Android: How do bluetooth UUIDs work?

Connecting and disconnecting to Bluetooth devices has been giving various results on Windows Phone/Desktop 8.1. I have been using the `Windows.Devices.Bluetooth.Rfcomm` namespace and I have tried to connect several devices with different Bluetooth versions/classes.

* Version 1.2 (Class 1 and 2)
* Version 2.0 (Class 1 and 2)
* Version 2.1 (Class 1 and 2)
- Tested on Nokia Lumia 625 and Lumia 635, Dell Latitude E6500 and a Dell Precision M6400.

*Whenever I try to connect to either of the 2.0 or 2.1 devices there are issues. The first time I try to connect to each of the devices everything will go fine and the connection will open. When I subsequently close the connection and re-connect the device, the trouble starts.* 
During the re-connect the connection will never open and the debugger will throw a System.Exception :

    &gt; Message: No further data is available.

Also, when the connection fails the Windows 8.1 devices will keep trying to (unsuccessfully) connect to the Bluetooth Devices by themselves, even when my own application is terminated. Sometimes the Windows 8.1 device will also show the Bluetooth device as connected, while the device visually shows that it&#39;s not connected anymore. The only way to reconnect the Bluetooth device is to unpair it and shutdown/restart Bluetooth on the Windows device.

Whenever I try to make a new call to `DeviceInformation` after a failed connect it will refuse to return the device that I earlier tried to connect.

    &gt; Message: The service cannot be found in the specified name space.

Odd result, the 1.2 devices work perfectly.

Manifest File:

    &lt;m2:DeviceCapability Name=&quot;bluetooth.rfcomm&quot;&gt;
      &lt;m2:Device Id=&quot;any&quot;&gt;
        &lt;m2:Function Type=&quot;serviceId:00001101-0000-1000-8000-00805F9B34FB&quot;/&gt;
      &lt;/m2:Device&gt;
    &lt;/m2:DeviceCapability&gt;

Selecting Device:

    Guid RfcommChatServiceUuid = Guid.Parse(&quot;00001101-0000-1000-8000-00805F9B34FB&quot;);
    await DeviceInformation.FindAllAsync(RfcommDeviceService.GetDeviceSelector(RfcommServiceId.FromUuid(RfcommChatServiceUuid)));

Connecting:(id = chatserviceid)

    StreamSocket _socket;    
    RfcommDeviceService service = await RfcommDeviceService.FromIdAsync(deviceInformation1._id);
    await _socket.ConnectAsync(service.ConnectionHostName, service.ConnectionServiceName);

Disconnecting:

    this._socket.Dispose();
    this._socket = null;

I&#39;ve researched the MSDN, code samples, demo&#39;s, channel-9 video&#39;s and StackOverflow, no resource can tell me if there are issues with `Windows.Devices.Bluetooth.Rfcomm`.

Is there someone who recognizes these odd results? Am I doing something wrong? 

- [Similar problem was observed here][1]

- [Link to MSDN issue][2]

UPDATE: Working with Windows Phone 8.1 GDR2 is a possible solution. 

NOTE: For myself and several other people this update still gives the same issues.


  [1]: https://stackoverflow.com/questions/27122484/rfcomm-connection-works-unstable/
  [2]: https://social.msdn.microsoft.com/Forums/windowsapps/en-US/c2d2cc7a-b966-42b2-9c04-835b125b404e/disconnecting-bluetooth-devices-with-windowsdevicesbluetoothrfcomm?forum=wpdevelop

(Dis)Connecting bluetooth devices with Windows.Devices.Bluetooth.Rfcomm (WP8.1)

I would like to check if bluetooth is enabled on any Android device periodically. Is there any intents that I could catch using BroadcastReceiver to do so, or is there other ways to do it?

How to check if bluetooth is enabled programmatically?

I have an android device acting as a hands free client device using hfp.

[Using the following code:][1] 

I am able to receive a call and the speakers and mic are working as expected.

My problem is that I can&#39;t seem to control the volume.


I tried using the following lines of code to find the correct stream, but none of them seem to work.

I tracked the volume command being sent from the phone to the client in the class `HeadsetClientStateMachine` , line #1822 in the following link: [HeadsetClientStateMachine from lolipop][2]

    case EVENT_TYPE_VOLUME_CHANGED:
        if (event.valueInt == HeadsetClientHalConstants.VOLUME_TYPE_SPK) {
            mAudioManager.setStreamVolume(AudioManager.STREAM_BLUETOOTH_SCO, event.valueInt2, AudioManager.FLAG_SHOW_UI);
            mVgsFromStack = true;
           Log.d(TAG, &quot;EventVolumeChange STREAM_BLUETOOTH_SCO value: &quot; + event.valueInt2);
        }

When I change the volume on the phone, I do see the log showing the updated value of the sound, which means that the `setStreamVolume()` method is being called, but the volume doesn&#39;t change.

Does anyone know what could be causing this issue?


**EDIT:**

I am still looking for an answer and am now looking toward the audio HAL implementation. I suspect that the link between the HAL and the audio driver is somehow incorrect... I don&#39;t know much about low level implementation and am not sure what I should be looking for.


  [1]: http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android-apps/5.0.0_r1/com/android/bluetooth/hfpclient/
  [2]: http://grepcode.com/file_/repository.grepcode.com/java/ext/com.google.android/android-apps/5.0.0_r1/com/android/bluetooth/hfpclient/HeadsetClientStateMachine.java/?v=source

Bluetooth hands free client volume control

Can an Android device act as an iBeacon and figure out when other Android devices come in its range? Do those other Android devices need to have Bluetooth turned on?

If a customer comes into my shop and he doesn&#39;t have my app installed on his device, can iBeacon work, or must he install the app first? There are so many customers are visiting our shop daily, but if they don&#39;t have my app installed, does the iBeacon concept work?

Can an Android device act as an iBeacon?

I have an app with a button on it that I use to turn BT on and off. I have the following code in there;

    public void buttonFlip(View view) {
        flipBT();
        buttonText(view);
    }
  
    public void buttonText(View view) {  
        Button buttonText = (Button) findViewById(R.id.button1);
        if (mBluetoothAdapter.isEnabled() || (mBluetoothAdapter.a)) {
            buttonText.setText(R.string.bluetooth_on);	
        } else {
            buttonText.setText(R.string.bluetooth_off);
        }
    }

    private void flipBT() {
        if (mBluetoothAdapter.isEnabled()) {
            mBluetoothAdapter.disable();	
        } else {
            mBluetoothAdapter.enable();
        }
    }

I&#39;m calling button Flip, which flips the BT state, and then calls ButtonText, which should update the UI. However, the issue I&#39;m having is, it takes a few seconds for BT to turn on - and during these seconds, the BT status is not enabled, making my button say Bluetooth off, even if it will be on in 2 seconds.

I found the `STATE_CONNECTING` constant in the BluetoothAdapter android documentation, but... I simply don&#39;t know how to use it, being a newbie and all.

So, I&#39;ve got two questions:

1. Is there a way to dynamically tie a UI element (such as a button or image) to a BT state, so that when the BT state changes, the button will change as well?
2. Otherwise, I would want to press the button and get the correct state (I would like for it to say BT on, even if it&#39;s only connecting, since it will be on in 2 seconds). How do I do this?

Detecting state changes made to the BluetoothAdapter?

I recently bought chinesse device that connects via bluetooth with android phone / tablet. Since there is no application availible for windows / linux I want to create one for personal usage.

Usually phone connects to the device and exchanges some data. I connected PC to the device and looked into serial debugger and menaged to discover the protocol (one way only). Phone sends only one command to the device. But this time I&#39;m not able to find out what it containts. 

Is there any software that will allow me to look into data sent via bluetooth? I tried decompiling the app, but it looks really unfriendly.

Thanks.



Sniffing/logging your own Android Bluetooth traffic

Device used for testing: Nexus 4, Android 4.3

Connection is working fine but the `onCharacteristicChanged`Method of my callback is never called. However I am registering for notifications using `setCharacteristicNotification(char, true)` inside `onServicesDiscovered` and that function even returns true.

Device log (there are actually _no_ messages at all when notifications _should_ appear / are sent via the Bluetooth device):

    07-28 18:15:06.936  16777-16809/de.ffuf.leica.sketch D/BluetoothGatt: setCharacteristicNotification() - uuid: 3ab10101-f831-4395-b29d-570977d5bf94 enable: true
    07-28 18:15:06.936    4372-7645/com.android.bluetooth D/BtGatt.GattService: registerForNotification() - address=C9:79:25:34:19:6C enable: true
    07-28 18:15:06.936    4372-7645/com.android.bluetooth D/BtGatt.btif: btif_gattc_reg_for_notification
    07-28 18:15:06.946    4372-7645/com.android.bluetooth D/BtGatt.btif: btgattc_handle_event: Event 1018
    07-28 18:15:06.946    4372-7645/com.android.bluetooth D/BtGatt.GattService: onRegisterForNotifications() - address=null, status=0, registered=1, charUuid=3ab10101-f831-4395-b29d-570977d5bf94
    07-28 18:15:06.946    4372-7645/com.android.bluetooth D/BtGatt.btif: btgattc_handle_event: Event 1016
    07-28 18:15:06.946    4372-7645/com.android.bluetooth D/BtGatt.btif: btgattc_handle_event: Event 1018
    07-28 18:15:06.946    4372-7645/com.android.bluetooth D/BtGatt.GattService: onRegisterForNotifications() - address=null, status=0, registered=1, charUuid=3ab10102-f831-4395-b29d-570977d5bf94
    07-28 18:15:06.946    4372-7645/com.android.bluetooth D/BtGatt.btif: btgattc_handle_event: Event 1016
    07-28 18:15:06.946    4372-7684/com.android.bluetooth E/bt-btif: already has a pending command!!
    07-28 18:15:06.946    4372-7645/com.android.bluetooth D/BtGatt.btif: btgattc_handle_event: Event 1013
    07-28 18:15:06.946    4372-7684/com.android.bluetooth E/bt-btif: already has a pending command!!
    07-28 18:15:06.946    4372-7645/com.android.bluetooth D/BtGatt.btif: btgattc_handle_event: Event 1013
    07-28 18:15:06.946    4372-7684/com.android.bluetooth E/bt-btif: already has a pending command!!
    07-28 18:15:06.976    4372-7645/com.android.bluetooth D/BtGatt.btif: btif_gattc_upstreams_evt: Event 9

GATT Notifications work fine using iOS and the app basically does the same as on Android (registering for notification etc.).

Has anyone else experienced this with a possible solution?

Android BLE API: GATT Notification not received

Is it possible to run an iOS 7 device as a Bluetooth LE peripheral (iBeacon) and have it advertise in the background?  I have been able to get it to advertise in the foreground with the code below and can see it from another iOS device but as soon as I go back to the home screen it stops advertising.  I did add the bluetooth-peripheral background mode in the plist but that didn&#39;t seem to help although I do get the prompt saying the device wants to use bluetooth in the background.  Am I doing something wrong or is this just not possible in iOS 7?

    peripManager = [[CBPeripheralManager alloc] initWithDelegate:self queue:nil];

    - (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral
    {
      if (peripheral.state != CBPeripheralManagerStatePoweredOn) {
          return;
      }
    
      NSString *identifier = @&quot;MyBeacon&quot;;
      //Construct the region
      CLBeaconRegion *beaconRegion = [[CLBeaconRegion alloc] initWithProximityUUID:uuid identifier:identifier];
    
      //Passing nil will use the device default power
      NSDictionary *payload = [beaconRegion peripheralDataWithMeasuredPower:nil];
    
      //Start advertising
      [peripManager startAdvertising:payload];
    }

Here is the code that is on the receiving/listening end:

    - (void)locationManager:(CLLocationManager *)manager didRangeBeacons:(NSArray *)beacons
               inRegion:(CLBeaconRegion *)region
    {
    //Check if we have moved closer or farther away from the iBeacon…
    if (beacons.count &gt; 0) {
        CLBeacon *beacon = [beacons objectAtIndex:0];
        
        switch (beacon.proximity) {
            case CLProximityImmediate:
                [self log:[NSString stringWithFormat:@&quot;You&#39;re Sitting on it! %li&quot;, (long)beacon.rssi]];
                break;
            case CLProximityNear:
                [self log:[NSString stringWithFormat:@&quot;Getting Warmer! %li&quot;, (long)beacon.rssi]];
                break;
            default:
                [self log:[NSString stringWithFormat:@&quot;It&#39;s around here somewhere! %li&quot;, (long)beacon.rssi]];
                break;
        }
    }
    }

Run iPhone as an iBeacon in the background

I&#39;m interested in connecting to iOS-based devices over Bluetooth. I can see that the &quot;Local Network&quot; service is exposed, but I cannot find any extra information about it. Property stored under key 0x0204 looks like a Bonjour key.

Which protocol is used? How can one talk to the iOS device using Linux, Mac or one&#39;s own embedded device equipped with a Bluetooth chip?

Here&#39;s SDP data extracted using Bluetooth Explorer under OS X while the iOS device runs Gameloft&#39;s Star Battalion.

		{
			0x0000 = uint32(1330188565),
			0x0200 = uint32(2),
			0x0202 = string(004wD7l1A..0|0|0|ivucic-&#192;&#39;),
			0x030a = uint32(0),
			0x0009 = { { uuid16(11 15), uint16(256) } },
			0x0201 = string(_657o30a6rmst07&#192;),
			0x0005 = { uuid16(10 02) },
			0x0100 = string(Local Network),
			0x0001 = { uuid16(11 15) },
			0x0203 = string(004wd7l1a..0|0|0|ivucic-_657o30a6rmst07&#192;
			0xf000 = uint8(2),
			0x0204 = string(	txtvers=1state=A),
			0x0008 = uint8(255),
			0x0006 = { uint16(25966), uint16(106), uint16(256), uint16(26226), uint16(106), uint16(272), uint16(25701), uint16(106), uint16(288), uint16(27233), uint16(106), uint16(304) },
			0x0004 = { { uuid16(01 00), uint16(15) }, { uuid16(00 0f), uint16(256), { uint16(2048), uint16(2054) } } },
			0x0002 = uint32(0)
		},

Other partially relevant questions:

 * [PAN with Linux, iOS, Bluetooth, Bonjour, GameKit — Possible?](https://stackoverflow.com/questions/7251023/pan-with-linux-ios-bluetooth-bonjour-gamekit-possible) - Person can solve problem using Wi-Fi. Not solution here because embedded device will not have the way more expensive Wi-Fi chip.
 * [Bonjour over bluetooth WITHOUT Gamekit?](https://stackoverflow.com/questions/3844189/bonjour-over-bluetooth-without-gamekit) - Best answer does not end up providing technical details
 * [iOS bluetooth without GameKit](https://stackoverflow.com/questions/7230311/ios-bluetooth-without-gamekit) - Provides a solution for a jailbroken device, which is not applicable here.

---

Researching further with Apple&#39;s Bluetooth Explorer in OS X and `sdptool` in GNU/Linux, I have discovered that key `0x0001` (standing for &quot;protocol class&quot;), containing value of `0x1115`, stands for the &quot;PANU&quot; variant of &quot;PAN&quot; - a peer2peer variant. It is notable that OS X does not provide service-side (&#39;hosting&#39;) support for this protocol, despite supporting creation of a `0x1116` network, which is the &quot;NAP&quot; variant of &quot;PAN&quot; - a client/server variant.

This might be good news, but only if GameKit&#39;s session protocol does not have to be used. Hijacking the media-layer connection established by GameKit in order to send other UDP traffic would be ideal.

I&#39;ll still have to research whether or not this GameKit connection really is `0x1115`; that is, if it really is &quot;PANU&quot;. Does anyone have any further information?

---
Note while Bonjour automatically announced this Bluetooth service after iOS 3, this has changed with iOS 5. See the answer I posted on [how to establish Bluetooth connection without GameKit](https://stackoverflow.com/q/8273661/39974), where I handily documented information from Apple&#39;s [Technical Q&amp;A QA1753](http://developer.apple.com/library/ios/#qa/qa1753/_index.html#//apple_ref/doc/uid/DTS40011315).

---
A small amount of research with GNU/Linux did not result in a successful connection. It may be due to lack of knowledge on how to properly use `pand`. It may also be due to Bluetooth MAC based blocking. I&#39;d love info anyone may have to offer. If I research this further and stumble upon something interesting, I&#39;ll update this answer.

---
Results under Ubuntu. The service appears only when Bluetooth Bonjour is active.

    ivucica@ivucica-MacBook:~$ sdptool browse $ADDR #relevant data only
    Browsing ADDRESS_HERE ...
    Service Name: Local Network
    Service RecHandle: 0x4f491115
    Service Class ID List:
      &quot;PAN User&quot; (0x1115)
    Protocol Descriptor List:
      &quot;L2CAP&quot; (0x0100)
        PSM: 15
      &quot;BNEP&quot; (0x000f)
        Version: 0x0100
        SEQ8: 0 6
    Language Base Attr List:
      code_ISO639: 0x656e
      encoding:    0x6a
      base_offset: 0x100
      code_ISO639: 0x6672
      encoding:    0x6a
      base_offset: 0x110
      code_ISO639: 0x6465
      encoding:    0x6a
      base_offset: 0x120
      code_ISO639: 0x6a61
      encoding:    0x6a
      base_offset: 0x130
    Profile Descriptor List:
      &quot;PAN User&quot; (0x1115)
        Version: 0x0100
    
    ... and so on ...

Here&#39;s the attempt to connect:

    ivucica@ivucica-MacBook:~$ pand --connect $ADDR -n
    pand[3237]: Bluetooth PAN daemon version 4.98
    pand[3237]: Connecting to ADDRESS_HERE
    pand[3237]: Connect to ADDRESS_HERE failed. Connection refused(111)

Is some sort of authorization required? Enabling encryption, authentication, secure connection and forcing becoming a master doesn&#39;t seem to make any difference (`-AESM` options in various combinations).

Anyone has any ideas?

---
Huh!

&lt;pre&gt;ivucica@ivucica-MacBook:~$ sudo hcidump
HCI sniffer - Bluetooth packet analyzer ver 2.2
device: hci0 snap_len: 1028 filter: 0xffffffff
&lt; HCI Command: Create Connection (0x01|0x0005) plen 13
    bdaddr ADDRESS_HERE ptype 0xcc18 rswitch 0x01 clkoffset 0x0000
    Packet type: DM1 DM3 DM5 DH1 DH3 DH5 
&gt; HCI Event: Command Status (0x0f) plen 4
    Create Connection (0x01|0x0005) status 0x00 ncmd 1
&gt; HCI Event: Role Change (0x12) plen 8
    status 0x00 bdaddr ADDRESS_HERE role 0x01
    Role: Slave
&gt; HCI Event: Connect Complete (0x03) plen 11
    status 0x00 handle 12 bdaddr ADDRESS_HERE type ACL encrypt 0x00
&lt; HCI Command: Read Remote Supported Features (0x01|0x001b) plen 2
    handle 12
&gt; HCI Event: Command Status (0x0f) plen 4
    Read Remote Supported Features (0x01|0x001b) status 0x00 ncmd 1
&gt; HCI Event: Read Remote Supported Features (0x0b) plen 11
    status 0x00 handle 12
    Features: 0xbf 0xfe 0x8f 0xfe 0x9b 0xff 0x79 0x83
&lt; HCI Command: Read Remote Extended Features (0x01|0x001c) plen 3
    handle 12 page 1
&gt; HCI Event: Command Status (0x0f) plen 4
    Read Remote Extended Features (0x01|0x001c) status 0x00 ncmd 1
&gt; HCI Event: Max Slots Change (0x1b) plen 3
    handle 12 slots 5
&gt; HCI Event: Read Remote Extended Features (0x23) plen 13
    status 0x00 handle 12 page 1 max 1
    Features: 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x00
&lt; HCI Command: Remote Name Request (0x01|0x0019) plen 10
    bdaddr ADDRESS_HERE mode 2 clkoffset 0x0000
&gt; HCI Event: Command Status (0x0f) plen 4
    Remote Name Request (0x01|0x0019) status 0x00 ncmd 1
&gt; HCI Event: Remote Name Req Complete (0x07) plen 255
    status 0x00 bdaddr ADDRESS_HERE name &#39;Evil iPad&#39;
&lt; HCI Command: Authentication Requested (0x01|0x0011) plen 2
    handle 12
&gt; HCI Event: Command Status (0x0f) plen 4
    Authentication Requested (0x01|0x0011) status 0x00 ncmd 1
&gt; HCI Event: Link Key Request (0x17) plen 6
    bdaddr ADDRESS_HERE
&lt; HCI Command: Link Key Request Reply (0x01|0x000b) plen 22
    bdaddr ADDRESS_HERE key B05AEA095C06217B2ACE9958DA722C91
&gt; HCI Event: Command Complete (0x0e) plen 10
    Link Key Request Reply (0x01|0x000b) ncmd 1
    status 0x00 bdaddr ADDRESS_HERE
&gt; HCI Event: Auth Complete (0x06) plen 3
    status 0x00 handle 12
&lt; HCI Command: Set Connection Encryption (0x01|0x0013) plen 3
    handle 12 encrypt 0x01
&gt; HCI Event: Command Status (0x0f) plen 4
    Set Connection Encryption (0x01|0x0013) status 0x00 ncmd 1
&gt; HCI Event: Encrypt Change (0x08) plen 4
    status 0x00 handle 12 encrypt 0x01
&lt; ACL data: handle 12 flags 0x00 dlen 10
    L2CAP(s): Info req: type 2
&gt; HCI Event: Number of Completed Packets (0x13) plen 5
    handle 12 packets 1
&gt; ACL data: handle 12 flags 0x02 dlen 16
    L2CAP(s): Info rsp: type 2 result 0
      Extended feature mask 0x02a8
        Enhanced Retransmission mode
        FCS Option
        Fixed Channels
        Unicast Connectless Data Reception
&lt; ACL data: handle 12 flags 0x00 dlen 10
    L2CAP(s): Info req: type 3
&gt; HCI Event: Number of Completed Packets (0x13) plen 5
    handle 12 packets 1
&gt; ACL data: handle 12 flags 0x02 dlen 20
    L2CAP(s): Info rsp: type 3 result 0
      Fixed channel list 0x00000006
        L2CAP Signalling Channel
        L2CAP Connless
&lt; ACL data: handle 12 flags 0x00 dlen 12
    L2CAP(s): Connect req: psm 15 scid 0x0040
&gt; HCI Event: Number of Completed Packets (0x13) plen 5
    handle 12 packets 1
&gt; ACL data: handle 12 flags 0x02 dlen 16
    L2CAP(s): Connect rsp: dcid 0x0000 scid 0x0040 result 2 status 0
      Connection refused - PSM not supported
&gt; HCI Event: Disconn Complete (0x05) plen 4
    status 0x00 handle 12 reason 0x13
    Reason: Remote User Terminated Connection
&lt;/pre&gt;

This?
&lt;pre&gt;
&gt; ACL data: handle 12 flags 0x02 dlen 16
    L2CAP(s): Connect rsp: dcid 0x0000 scid 0x0040 result 2 status 0
      Connection refused - PSM not supported
&lt;/pre&gt;

Using iOS GameKit&#39;s &quot;Bluetooth Bonjour&quot; with other platforms

I&#39;ve been reading up on how to transfer data between iOS devices over Bluetooth using GameKit.  I&#39;m not writing a game, per se, but do have a need to transfer a small amount of binary data between two devices.  Between two iOS devices, this is easy enough.  However, I was wondering if it is possible to transfer data between an iOS device and an Android device via the same mechanism.  

Has anyone come across documentation/tutorial that would explain how to do this?  Is it even technically possible?  Or has Apple put in some sort of restriction that would prevent this?

The other option I discovered was Bonjour over Bluetooth.  Would this be a more suitable option for this type of operation?

Transfer data between iOS and Android via Bluetooth?

I want to use the Bluetooth LE functions in .NET Core (specifically, BluetoothLEAdvertisementWatcher) to write a scanner which logs information to a file. This is to run as a desktop application and preferably as a command line app.

Constructors like System.IO.StreamWriter(string) are not available, apparently. How do I create a file and write to it?

I would be just as happy to be able to do a System.Console.WriteLine(string) but that doesn&#39;t seem to be available under .NET Core either.

Update: To clarify, if I could have a program that looks like this run without error, I&#39;ll be off to the races.

    using System;
    using Windows.Devices.Bluetooth.Advertisement;

    namespace ConsoleApplication
    {
        public class Program
        {
            public static void Main(string[] args)
            {
                BluetoothLEAdvertisementWatcher watcher = new BluetoothLEAdvertisementWatcher();
                Console.WriteLine(&quot;Hello, world!&quot;);
            }
        }
    }

Update 2: Here&#39;s the project.json file:

    {
      &quot;dependencies&quot;: {
        &quot;Microsoft.NETCore.UniversalWindowsPlatform&quot;: &quot;5.0.0&quot;
      },
      &quot;frameworks&quot;: {
        &quot;uap10.0&quot;: {}
      },
      &quot;runtimes&quot;: {
        &quot;win10-arm&quot;: {},
        &quot;win10-arm-aot&quot;: {},
        &quot;win10-x86&quot;: {},
        &quot;win10-x86-aot&quot;: {},
        &quot;win10-x64&quot;: {},
        &quot;win10-x64-aot&quot;: {}
      }
    }

The output of the command `dotnet -v run` contains this error message:

    W:\src\dotnet_helloworld&gt;dotnet -v run
    ...
    W:\src\dotnet_helloworld\Program.cs(2,15): error CS0234: The type or namespace name &#39;Devices&#39; does not exist in the namespace &#39;Windows&#39; (are you missing an assembly reference?)
    ...


How to write to a file in .NET Core?

I want to connect 3 devices via bluetooth (My Droid must connect to 2 bluetooth devices). I &#39;ve connected my Droid to 1 device using Bluetooth chat How should I modify it for multiple bluetooth devices? Could you help me please?

Multiple bluetooth connection

Can anybody give me Android `Bluetooth` communication tutorial links or hints? Please don&#39;t tell me to refer to the BluetoothChat example, I can only understand how to discover and connect to devices but don&#39;t know how to send and receive the data over Bluetooth.

I am actually working on an Android and embedded `Bluetooth` device project.
Please help me out.


Android Bluetooth Example

Using CoreBluetooth I want to send data from iPhone to Mac. For this I wrote code like iPhone as &#39;Peripheral&#39; and Mac as &#39;Central&#39;.
 
It works perfectly, but sometimes it disconnects directly and then it continuously connects and disconnects.
 
Some times when it is trying to reconnect, In Central it directly calls &#39;didDisconnectPeripheral&#39; delegate method. But some times it has error &quot;The handle is invalid&quot; in &#39;didUpdateNotificationStateForCharacteristic&#39;.
 
I referred all the links in net. But I am not able to solve this problem. I thought in iPhone it was storing Bluetooth cache.
 
Please suggest a solution how to solve &quot;The handle is invalid&quot; error?
 
 
Below are some of the important methods.
 
For Peripheral I wrote Code like below.
 
In Appdelegate:
 

    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
    {
    self.peripheral = [[PeripheralServerObject alloc] init];
    self.peripheral.serviceUUID = [CBUUID UUIDWithString:@&quot;4w24&quot;];
    return YES;
    }

 
In Peripheral Object File:
 

    //To Check Bluetooth State
    - (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral {
        switch (peripheral.state) {
            case CBPeripheralManagerStatePoweredOn:
                [self enableService];
                break;
            case CBPeripheralManagerStatePoweredOff: {
                [self disableService];
                break;
            }
    }
     
    // To Add characteristics to Service
    - (void)enableService
    {
    [self.peripheral removeAllServices];
     self.service = [[CBMutableService alloc]
                        initWithType:self.serviceUUID primary:YES];
                    
    self.authChar =
            [[CBMutableCharacteristic alloc] initWithType:[CBUUID UUIDWithString:@&quot;a86e&quot;]
                                               properties:CBCharacteristicPropertyNotify
                                                    value:nil
                                              permissions:CBAttributePermissionsReadable];
                                              
                                              
    self.respChar =
            [[CBMutableCharacteristic alloc] initWithType:[CBUUID UUIDWithString:@&quot;a86f&quot;]
                                               properties:CBCharacteristicPropertyWriteWithoutResponse
                                                    value:nil
                                              permissions:CBAttributePermissionsWriteable];
                                              
    self.service.characteristics = @[ self.authChar, self.respChar ];
     
        // Add the service to the peripheral manager.
        [self.peripheral addService:self.service];
    }
    
    //Peripheral Manager delegate method will be called after adding service.
    
    - (void)peripheralManager:(CBPeripheralManager *)peripheral
                didAddService:(CBService *)service
                        error:(NSError *)error {
        
        [self startAdvertising];
        
    }
     
    //To disable service 
    - (void)disableService
    {
     [self.peripheral stopAdvertising];
     [self.peripheral removeAllServices];
    }
     
    //To enable a service again.
    -(void)refreshService {
        [self disableService];
        [self enableService];
    }
     
     
    If central subscribes the characteristic, then the below peripheral delegate method will be called. In this I implemented code to send data
     
    - (void)peripheralManager:(CBPeripheralManager *)peripheral
                      central:(CBCentral *)central
    didSubscribeToCharacteristic:(CBCharacteristic *)characteristic {
      
        self.dataTimer = [NSTimer scheduledTimerWithTimeInterval:10.0
                                                          target:self
                                                        selector:@selector(sendData)
                                                        userInfo:nil
                                                         repeats:YES];
    }
     
    - (void)sendData
    {
    Here I am sending data like [Apple&#39;s BTLE Example Code][1]  
    }
     
    
    //If unsubscribed then I am invalidating timer and refreshing service
     
    - (void)peripheralManager:(CBPeripheralManager *)peripheral
                      central:(CBCentral *)central
    didUnsubscribeFromCharacteristic:(CBCharacteristic *)characteristic {
        
        if (self.dataTimer)
            [self.dataTimer invalidate];
        [self refreshService];
            
    }

 
For Mac I wrote a peripheral delegate methods.
 

    //I enables the notification for &quot;a860&quot; Characteristic.
     
    - (void)peripheral:(CBPeripheral *)peripheral
    didDiscoverCharacteristicsForService:(CBService *)service
    error:(NSError *)error {
     
         CBUUID * authUUID = [CBUUID UUIDWithString:@&quot;a86e&quot;];
           for (CBCharacteristic *characteristic in service.characteristics) {
     
            if ([characteristic.UUID isEqual:authUUID]) {
             }
            [self.connectedPeripheral setNotifyValue:YES
                                       forCharacteristic:characteristic];
             }
    }
     
    -(void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
       if (error) {
       Here I am getting error sometimes &quot;The handle is invalid&quot;.
        }
    }

 


  [1]: https://developer.apple.com/Library/ios/samplecode/BTLE_Transfer/Introduction/Intro.html

Setting Notifications on Characteristic results in Invalid Handle error

I am trying to find a bluetooth packet sniffer to capture bluetooth signals from close by devices. I would like for this application to work on mac osx. I have had difficulty finding anything at all so my requirements are low right now - something that shows signal strength and mac address would be a good start. 

Bluetooth sniffer - preferably mac osx

Is there a way, using the Android SDK, to programmatically connect to an already-paired Bluetooth device?

In other words: I can go into Settings -&gt; Wireless &amp; networks -&gt; Bluetooth settings, and tap the device (listed as &quot;Paired but not connected&quot;), at which point it will connect. I&#39;d like to be able to do this programmatically, but don&#39;t see a way to do this.

I see the options to create an RFCOMM socket, and for a SPP device, I&#39;m assuming that&#39;ll do the connection part as well, but for an A2DP device, where the actual data transfer will be handled by the OS rather than by my app, I think that&#39;s not applicable?


Programmatically connect to paired Bluetooth device

I want to build a c file based on BlueZ but seems no bluetooth.h file in my system.

    fatal error: bluetooth/bluetooth.h: No such file or directory

I am sure the bluetooth dongle is running correctly and I have built Bluez successfully.

**Update**

For my case, I find the bluetooth.h in /user/include/bluetooth folder

Where is the bluetooth/bluetooth.h located in Linux?

My project requires to receive&amp;send bluetooth signal, and I am pretty new to react-native so which component I can use in react-native for bluetooth related functionality?

Bluetooth in react-native

I&#39;m trying to do this:

        BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
    	if (bt == null){
    		//Does not support Bluetooth
    		status.setText(&quot;Your device does not support Bluetooth&quot;);
    	}else{
    		//Magic starts. Let&#39;s check if it&#39;s enabled
    		if (!bt.isEnabled()){
    			Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
    		    startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
    		}	
    	}

But I get this error:

&gt; REQUEST_ENABLE_BT cannot be resolved to a variable

How can I fix it?

Error checking if Bluetooth is enabled in Android (REQUEST_ENABLE_BT cannot be resolved to a variable)

- **Goal**: Use BlueZ and an Bluetooth 4LE dongle to create a peripheral that advertises the bluetooth equivalent of &quot;Hello World&quot;.

- **Where I&#39;m At**: I&#39;ve currently got the BlueZ stack setup and downloaded, I can use the hci tool to recognize and see the Bluetooth dongle. I&#39;ve tinkered with hciconfig leadv but I&#39;m just not quite getting it/understanding what&#39;s going on.

- **What Help I Think I Need**: I need to get it to the next step. If anyone can either point me towards a good resource, walk me through this, or anything, It would be much appreciated. If I need to do additional leg(search)work I can but I&#39;ve scoured Google and SO with as many different derivatives of this question as I can think of.

*I tagged this as CoreBluetooth as well in hopes that maybe an iOS dev has tinkered with this at some point.

EDIT: In response to a comment, It seems prudent to state what my end goal is. I&#39;d ultimately like to advertise via the dongle the simplest of simple messages/signals and pick that up on an iOS device (CoreBluetooth). I&#39;ve been able to get the iOS side of things working well (tons of documentation compared to the Linux side of things) but that hard part for me is getting this adapter setup as a peripheral. The BlueZ stack is a terrible enigma for me.

EDIT: After more digging, I eventually stumbled upon this post: https://stackoverflow.com/questions/16052882/raspberry-pi-bluetooth-4-0-connection.
This has led me toward the topic of a GATT server, I&#39;ll continue pursuing this topic.

EDIT: Alright so my quest for learning goes on. Over the past couple of days I&#39;ve dived deeper into the hci*, sdptool, and gatttool tools. I&#39;ve gotten to the point of being able to set the adapter to advertise, &quot;hciconfig hci0 leadv&quot;. At this point, I can successfully &quot;see&quot; the adapter, but I cannot actually read anything off of it. I&#39;m not even seeing the friendly name. I&#39;ll keep trucking on but as always, any help/suggestions are more than welcome.

EDIT: Relevant Link, solid overview of Bluetooth LE pertaining to iOS.
https://developer.apple.com/library/content/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts/AboutCoreBluetooth/Introduction.html#//apple_ref/doc/uid/TP40013257-CH1-SW1


LAST EDIT: Hey all, this link covers how to create an iBeacon using a Raspberry Pi + BlueZ...
http://www.wadewegner.com/2014/05/create-an-ibeacon-transmitter-with-the-raspberry-pi/

Use BlueZ Stack As A Peripheral (Advertiser)


I am currently working on an iOS application based on bluetooth low energy devices. In order to get a unique identifier to compare the peripherals got, I have to get the MAC address of the peripherals. 

It is observed that the UUID property of a peripheral device varies across iOS devices and also for the peripheral device to get a UUID, it will have to get connected to a master device at least once. Since I have to deal with check-in&#39;s I don&#39;t want to establish a connection. As I went through the bluetooth services portal, I found that the device information itself is a service, which couldn&#39;t be retrieved unless a connection has been established between the master iOS device and the peripheral bluetooth low energy device.

I found that in Android we get the entire information of the device, including its MAC address (using getAddress()) when we get the response from the device on scanning itself.

I didn&#39;t find any properties in CBPeripheral class related to the device address.
Another way to get a unique parameter would be to customize the advertisement data to send additional information regarding the device, which requires more work on firmware side.

So is there any way in iOS that I could get the MAC address of the bluetooth low energy peripheral without establishing a connection?

Any help would be greatly appreciated.


Get MAC address of bluetooth low energy peripheral in iOS

I am new to android. I am designing an android application that receives serial data from a hardware device through bluetooth. I am working on Htc desire S. I used the sample Bluetooth chat code to receive data. But the data received is incorrect. It misses some values. Can anyone please provide me any other sample code to receive large amount of data through bluetooth and save it in a file.

How to receive serial data using android bluetooth

Android Bluetooth Low Energy API implements 1 method to connect to the device `connectGatt()` but 2 methods to close the connection `disconnect()` and `close()`.


Documentation says:

 - `disconnect()`: Disconnects an established connection, or cancels a connection attempt
       currently in progress.
   
 - `close()`: Application should call this method as early as possible after it is done with
         this GATT client.

The source code of [BluetoothGatt.java][1] shows that close() unregisters the application and disconnect() disconnect the client. However it does not say what that actually means. I mean, if there is only 1 way to connect to the client, why there are 2 ways to close/disconnect the connection?


  [1]: https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/bluetooth/BluetoothGatt.java

Difference between close() and disconnect()?

I&#39;m currently creating an iPhone app (Xcode 4.3.1, IOS 5) that could use Bluetooth devices! Main goal of this application is indoor navigation (GPS inside buildings isn&#39;t really accurate).

The only solution I see here (to keep my app on AppStore) is to try scan for available bluetooth devices!

I tried to use CoreBluetooth framework, but I don&#39;t get list of available devices! 
Maybe I don&#39;t use these functions correctly


    #import &lt;UIKit/UIKit.h&gt;
    #import &lt;CoreBluetooth/CoreBluetooth.h&gt;
    
    @interface AboutBhyperView : UIViewController &lt;CBPeripheralDelegate, CBCentralManagerDelegate&gt;
    {
        CBCentralManager *mgr;
    }
    @property (readwrite, nonatomic) CBCentralManager *mgr;
    @end
    
    
    
    - (void)viewDidLoad
    {
        [super viewDidLoad];
    
        mgr = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
    }
    
    
    - (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {
       
       
        NSLog([NSString stringWithFormat:@&quot;%@&quot;,[advertisementData description]]);
    }
    
    -(void)centralManager:(CBCentralManager *)central didRetrievePeripherals:(NSArray *)peripherals{
        NSLog(@&quot;This is it!&quot;);
    }
    
    
    - (void)centralManagerDidUpdateState:(CBCentralManager *)central{ 
        NSString *messtoshow;
       
        switch (central.state) {
            case CBCentralManagerStateUnknown:
            {
                messtoshow=[NSString stringWithFormat:@&quot;State unknown, update imminent.&quot;];
                break;
            }
            case CBCentralManagerStateResetting:
            {
                messtoshow=[NSString stringWithFormat:@&quot;The connection with the system service was momentarily lost, update imminent.&quot;];
                break;
            }
            case CBCentralManagerStateUnsupported:
            {
                messtoshow=[NSString stringWithFormat:@&quot;The platform doesn&#39;t support Bluetooth Low Energy&quot;];
                break;
            }
            case CBCentralManagerStateUnauthorized:
            {
                messtoshow=[NSString stringWithFormat:@&quot;The app is not authorized to use Bluetooth Low Energy&quot;];
                break;
            }
            case CBCentralManagerStatePoweredOff:
            {
                messtoshow=[NSString stringWithFormat:@&quot;Bluetooth is currently powered off.&quot;];
                break;
            }
            case CBCentralManagerStatePoweredOn:
            {
                messtoshow=[NSString stringWithFormat:@&quot;Bluetooth is currently powered on and available to use.&quot;];
                [mgr scanForPeripheralsWithServices:nil options:nil];
                //[mgr retrieveConnectedPeripherals];
    
    //--- it works, I Do get in this area!

                break;
            }   
    
        }
        NSLog(messtoshow); 
    } 


I&#39;m not sure about this line, how to pass correct parameters?

    [mgr scanForPeripheralsWithServices:nil options:nil];

I took a look into apple reference .. and I still don&#39;t understand what&#39;s that CBUUID ???
Every device has some bluetooth id? where can I find it?

    - (void)scanForPeripheralsWithServices:(NSArray *)serviceUUIDs options:(NSDictionary *)options;

Parameters
serviceUUIDs - An array of CBUUIDs the app is interested in. 
options - A dictionary to customize the scan, see CBCentralManagerScanOptionAllowDuplicatesKey.


Is there any other way to use Bluetooth on IOS? I mean, older frameworks that don&#39;t use BLE 4.0!


any advice would be appreciated!

thanks!



How to get list of available Bluetooth devices?

I want to discover `bluetooth` devices in range, list and pair to them on click. I used following code but its just closing application when I click on device name which I want to pair.

I want to know mistake in my code or any other way to do what i need.

    

    package com.marakana;
    
        import java.util.Set;
    
        import android.app.Activity;
        import android.bluetooth.BluetoothAdapter;
        import android.bluetooth.BluetoothDevice;
        import android.content.BroadcastReceiver;
        import android.content.Context;
        import android.content.Intent;
        import android.content.IntentFilter;
        import android.os.Bundle;
        import android.util.Log;
        import android.view.View;
        import android.view.Window;
        import android.view.View.OnClickListener;
        import android.widget.AdapterView;
        import android.widget.ArrayAdapter;
        import android.widget.Button;
        import android.widget.ListView;
        import android.widget.TextView;
        import android.widget.AdapterView.OnItemClickListener;
    
     
        public class BluetoothDemo extends Activity {
        // Debugging
        private static final String TAG = &quot;DeviceListActivity&quot;;
        private static final boolean D = true;
    
        // Return Intent extra
        public static String EXTRA_DEVICE_ADDRESS = &quot;device_address&quot;;
    
        // Member fields
        private BluetoothAdapter mBtAdapter;
        private ArrayAdapter&lt;String&gt; mPairedDevicesArrayAdapter;
        private ArrayAdapter&lt;String&gt; mNewDevicesArrayAdapter;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    
            // Setup the window
            requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
            setContentView(R.layout.device_list);
    
            // Set result CANCELED incase the user backs out
            setResult(Activity.RESULT_CANCELED);
    
            // Initialize the button to perform device discovery
            Button scanButton = (Button) findViewById(R.id.button_scan);
            scanButton.setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
                    doDiscovery();
                    v.setVisibility(View.GONE);
                }
            });
    
            // Initialize array adapters. One for already paired devices and
            // one for newly discovered devices
            mPairedDevicesArrayAdapter = new ArrayAdapter&lt;String&gt;(this, R.layout.device_name);
            mNewDevicesArrayAdapter = new ArrayAdapter&lt;String&gt;(this, R.layout.device_name);
    
            // Find and set up the ListView for paired devices
            ListView pairedListView = (ListView) findViewById(R.id.paired_devices);
            pairedListView.setAdapter(mPairedDevicesArrayAdapter);
            pairedListView.setOnItemClickListener(mDeviceClickListener);
    
            // Find and set up the ListView for newly discovered devices
            ListView newDevicesListView = (ListView) findViewById(R.id.new_devices);
            newDevicesListView.setAdapter(mNewDevicesArrayAdapter);
            newDevicesListView.setOnItemClickListener(mDeviceClickListener);
    
            // Register for broadcasts when a device is discovered
            IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
            this.registerReceiver(mReceiver, filter);
    
            // Register for broadcasts when discovery has finished
            filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
            this.registerReceiver(mReceiver, filter);
    
            // Get the local Bluetooth adapter
            mBtAdapter = BluetoothAdapter.getDefaultAdapter();
    
            // Get a set of currently paired devices
            Set&lt;BluetoothDevice&gt; pairedDevices = mBtAdapter.getBondedDevices();
    
            // If there are paired devices, add each one to the ArrayAdapter
            if (pairedDevices.size() &gt; 0) {
                findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
                for (BluetoothDevice device : pairedDevices) {
                    mPairedDevicesArrayAdapter.add(device.getName() + &quot;\n&quot; + device.getAddress());
                }
            } else {
                String noDevices = getResources().getText(R.string.none_paired).toString();
                mPairedDevicesArrayAdapter.add(noDevices);
            }
        }
    
        @Override
        protected void onDestroy() {
            super.onDestroy();
    
            // Make sure we&#39;re not doing discovery anymore
            if (mBtAdapter != null) {
                mBtAdapter.cancelDiscovery();
            }
    
            // Unregister broadcast listeners
            this.unregisterReceiver(mReceiver);
        }
    
        /**
         * Start device discover with the BluetoothAdapter
         */
        private void doDiscovery() {
            if (D) Log.d(TAG, &quot;doDiscovery()&quot;);
    
            // Indicate scanning in the title
            setProgressBarIndeterminateVisibility(true);
            setTitle(R.string.scanning);
    
            // Turn on sub-title for new devices
            findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE);
    
            // If we&#39;re already discovering, stop it
            if (mBtAdapter.isDiscovering()) {
                mBtAdapter.cancelDiscovery();
            }
    
            // Request discover from BluetoothAdapter
            mBtAdapter.startDiscovery();
        }
    
        // The on-click listener for all devices in the ListViews
        private OnItemClickListener mDeviceClickListener = new OnItemClickListener() {
            public void onItemClick(AdapterView&lt;?&gt; av, View v, int arg2, long arg3) {
                // Cancel discovery because it&#39;s costly and we&#39;re about to connect
                mBtAdapter.cancelDiscovery();
    
                // Get the device MAC address, which is the last 17 chars in the View
                String info = ((TextView) v).getText().toString();
                String address = info.substring(info.length() - 17);
    
                // Create the result Intent and include the MAC address
                Intent intent = new Intent();
                intent.putExtra(EXTRA_DEVICE_ADDRESS, address);
    
                // Set result and finish this Activity
                setResult(Activity.RESULT_OK, intent);
                finish();
            }
        };
    
        // The BroadcastReceiver that listens for discovered devices and
        // changes the title when discovery is finished
        private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                String action = intent.getAction();
    
                // When discovery finds a device
                if (BluetoothDevice.ACTION_FOUND.equals(action)) {
                    // Get the BluetoothDevice object from the Intent
                    BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                    // If it&#39;s already paired, skip it, because it&#39;s been listed already
                    if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
                        mNewDevicesArrayAdapter.add(device.getName() + &quot;\n&quot; + device.getAddress());
                    }
                // When discovery is finished, change the Activity title
                } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
                    setProgressBarIndeterminateVisibility(false);
                    setTitle(R.string.select_device);
                    if (mNewDevicesArrayAdapter.getCount() == 0) {
                        String noDevices = getResources().getText(R.string.none_found).toString();
                        mNewDevicesArrayAdapter.add(noDevices);
                    }
                }
            }
        };
    }

   

             

Android + Pair devices via bluetooth programmatically

I am writing a test app in iOS 7 with the Core Bluetooth API. When I am testing the application I found that I am getting the following warning message:

 &gt; TestBluetooth[626:60b] CoreBluetooth[API MISUSE] &lt;CBCentralManager: 0x16d4c230&gt; can only accept commands while in the powered on state

Later I debugged app and found that, warning is coming from the following line of code:
 
    [manager scanForPeripheralsWithServices:array options:scanOptions];

So can anyone please tell me why I am getting this message in the console? 

There are bluetooth 4.0 android devices around me, but this app is not discovering them as peripheral device. So why it is not discovering bluetooth 4.0 LE Android devices as peripherals?

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