How to receive serial data using android bluetooth

Question

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

User · Answer

Take a look at incredible Bluetooth Serial class that has onResume   ability that helped me so much  I hope this helps

User · Answer

try this code    Activity   package Android Arduino Bluetooth  import android app Activity  import android bluetooth BluetoothAdapter  import android bluetooth BluetoothDevice  import android bluetooth BluetoothSocket  import android content Intent  import android os Bundle  import android os Handler  import android view View  import android widget TextView  import android widget EditText    import android widget Button  import java io IOException  import java io InputStream  import java io OutputStream  import java util Set  import java util UUID   public class MainActivity extends Activity   TextView myLabel  EditText myTextbox  BluetoothAdapter mBluetoothAdapter  BluetoothSocket mmSocket  BluetoothDevice mmDevice  OutputStream mmOutputStream  InputStream mmInputStream  Thread workerThread  byte   readBuffer  int readBufferPosition  int counter  volatile boolean stopWorker    Override public void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout main        Button openButton    Button findViewById R id open       Button sendButton    Button findViewById R id send       Button closeButton    Button findViewById R id close       myLabel    TextView findViewById R id label       myTextbox    EditText findViewById R id entry          Open Button     openButton setOnClickListener new View OnClickListener                 public void onClick View v                        try                                findBT                    openBT                              catch  IOException ex                               Send Button     sendButton setOnClickListener new View OnClickListener                 public void onClick View v                        try                                sendData                              catch  IOException ex                               Close button     closeButton setOnClickListener new View OnClickListener                 public void onClick View v                        try                                closeBT                              catch  IOException ex                           void findBT         mBluetoothAdapter   BluetoothAdapter getDefaultAdapter        if mBluetoothAdapter    null                myLabel setText  No bluetooth adapter available               if  mBluetoothAdapter isEnabled                  Intent enableBluetooth   new Intent BluetoothAdapter ACTION REQUEST ENABLE           startActivityForResult enableBluetooth  0              Set lt BluetoothDevice gt  pairedDevices   mBluetoothAdapter getBondedDevices        if pairedDevices size    gt  0                for BluetoothDevice device   pairedDevices                        if device getName   equals  MattsBlueTooth                                   mmDevice   device                  break                                    myLabel setText  Bluetooth Device Found       void openBT   throws IOException       UUID uuid   UUID fromString  00001101-0000-1000-8000-00805F9B34FB      Standard SerialPortService ID     mmSocket   mmDevice createRfcommSocketToServiceRecord uuid               mmSocket connect        mmOutputStream   mmSocket getOutputStream        mmInputStream   mmSocket getInputStream         beginListenForData         myLabel setText  Bluetooth Opened       void beginListenForData         final Handler handler   new Handler         final byte delimiter   10    This is the ASCII code for a newline character      stopWorker   false      readBufferPosition   0      readBuffer   new byte 1024       workerThread   new Thread new Runnable                 public void run                                        while  Thread currentThread   isInterrupted    amp  amp   stopWorker                               try                                        int bytesAvailable   mmInputStream available                                                if bytesAvailable  gt  0                                                byte   packetBytes   new byte bytesAvailable                           mmInputStream read packetBytes                           for int i 0 i lt bytesAvailable i                                                          byte b   packetBytes i                               if b    delimiter                                     byte   encodedBytes   new byte readBufferPosition        System arraycopy readBuffer  0  encodedBytes  0  encodedBytes length        final String data   new String encodedBytes   US-ASCII         readBufferPosition   0                                   handler post new Runnable                                                                         public void run                                                                                 myLabel setText data                                                                                                                                       else                                                               readBuffer readBufferPosition      b                                                                                                                   catch  IOException ex                                         stopWorker   true                                                        workerThread start       void sendData   throws IOException       String msg   myTextbox getText   toString        msg      n       mmOutputStream write msg getBytes         myLabel setText  Data Sent       void closeBT   throws IOException       stopWorker   true      mmOutputStream close        mmInputStream close        mmSocket close        myLabel setText  Bluetooth Closed          AND Here the layout    lt  xml version  1 0  encoding  utf-8   gt   lt RelativeLayout xmlns android  http   schemas android com apk res android  xmlns tools  http   schemas android com tools  android layout width  fill parent  android layout height  fill parent  tools ignore  TextFields HardcodedText   gt    lt TextView     android id    id label      android layout width  fill parent      android layout height  wrap content      android text  Type here     gt    lt EditText     android id    id entry      android layout width  fill parent      android layout height  wrap content      android layout below   id label      android background   android drawable editbox background    gt    lt Button     android id    id open      android layout width  wrap content      android layout height  wrap content      android layout alignParentRight  true      android layout below   id entry      android layout marginLeft  10dip      android text  Open    gt    lt Button     android id    id send      android layout width  wrap content      android layout height  wrap content      android layout alignTop   id open      android layout toLeftOf   id open      android text  Send    gt    lt Button     android id    id close      android layout width  wrap content      android layout height  wrap content      android layout alignTop   id send      android layout toLeftOf   id send      android text  Close    gt    lt  RelativeLayout gt    Here for Manifest  add to Application     permission must be enabled complete  lt manifest      gt        lt uses-permission android name  android permission BLUETOOTH ADMIN    gt       lt uses-permission android name  android permission BLUETOOTH    gt       lt application gt         lt  application gt   lt  manifest gt

User · Answer

The issue with the null connection is related to the findBT   function  you must change the device name from  MattsBlueTooth  to your device name as well as confirm the UUID for your service device  Use something like BLEScanner app to confrim both on Android

User · Answer

I tried this out for transmitting continuous data (float values converted to string) from my PC (MATLAB) to my phone. But, still my App misreads the delimiter '\n' and still data gets garbled. So, I took the character 'N' as the delimiter rather than '\n' (it could be any character that doesn't occur as part of your data) and I've achieved better transmission speed - I gave just 0.1 seconds delay between transmitting successive samples - with more than 99% data integrity at the receiver i.e. out of 2000 samples (float values) that I transmitted, only 10 were not decoded properly in my application.

My answer in short is: Choose a delimiter other than '\r' or '\n' as these create more problems for real-time data transmission when compared to other characters like the one I've used. If we work more, may be we can increase the transmission rate even more. I hope my answer helps someone!

[android] How to receive serial data using android bluetooth

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