Communication Bluetooth android-arduino

Question

I have modified the android app "Bluetooth Chat" that you can find in android sdk examples version 2.1 The app estabilished a bluetooth connection with arduino, and, when with the app I send 0 or 1, arduino send a simple message "You have pressed 0 or 1". It works if I test with eclipse's debug, but when I test with my smartphone, the result in the display is different, arduino's string is fragmented

example: smartphone: 0 -> arduino "You have pressed 0 or 1" smartphone display: "y" "ou pr"

The rest of the string was lost or not shown in the display. Can you help me? No error in logcat, only this bug.

This is the code:

public class BluetoothLampService {
    // Debugging
    private static final String TAG = "BluetoothLampService";
    private static final boolean D = true;

    // Name for the SDP record when creating server socket
    private static final String NAME = "BluetoothLamp";

    // Unique UUID for this application - Standard SerialPortService ID
   private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");



    // Member fields
    private final BluetoothAdapter Adapter;
    private final Handler Handler;
 //   private AcceptThread AcceptThread;
    private ConnectThread ConnectThread;
    private ConnectedThread ConnectedThread;
    private int State;

    // Constants that indicate the current connection state
    public static final int STATE_NONE = 0;       // we're doing nothing
    public static final int STATE_LISTEN = 1;     // now listening for incoming connections
    public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection
    public static final int STATE_CONNECTED = 3;  // now connected to a remote device

    /**
     * Constructor. Prepares a new BluetoothChat session.
     * @param context  The UI Activity Context
     * @param handler  A Handler to  messages back to the UI Activity
     */
    public BluetoothLampService(Context context, Handler handler) {
        Adapter = BluetoothAdapter.getDefaultAdapter();
        State = STATE_NONE;
        Handler = handler;
    }

    /**
     * Set the current state of the chat connection
     * @param state  An integer defining the current connection state
     */
    private synchronized void setState(int state) {
         State = state;

        // Give the new state to the Handler so the UI Activity can update
        Handler.obtainMessage(MainActivity.MESSAGE_STATE_CHANGE, state, -1).sendToTarget();
    }

    /**
     * Return the current connection state. */
    public synchronized int getState() {
        return State;
    }

    /**
     * Start the chat service. Specifically start AcceptThread to begin a
     * session in listening (server) mode. Called by the Activity onResume() */
    public synchronized void start() {

        // Cancel any thread attempting to make a connection
        if (ConnectThread != null) {ConnectThread.cancel(); ConnectThread = null;}

        // Cancel any thread currently running a connection
        if (ConnectedThread != null) {ConnectedThread.cancel(); ConnectedThread = null;}

        // Start the thread to listen on a BluetoothServerSocket
 //       if (AcceptThread == null) {
 //           AcceptThread = new AcceptThread();
 //           AcceptThread.start();
  //      }
        setState(STATE_LISTEN);
    }

    /**
     * Start the ConnectThread to initiate a connection to a remote device.
     * @param device  The BluetoothDevice to connect
     */
    public synchronized void connect(BluetoothDevice device) {

        // Cancel any thread attempting to make a connection
        if (State == STATE_CONNECTING) {
            if (ConnectThread != null) {ConnectThread.cancel(); ConnectThread = null;}
        }

        // Cancel any thread currently running a connection
        if (ConnectedThread != null) {ConnectedThread.cancel(); ConnectedThread = null;}

        // Start the thread to connect with the given device
        ConnectThread = new ConnectThread(device);
        ConnectThread.start();
        setState(STATE_CONNECTING);
    }

    /**
     * Start the ConnectedThread to begin managing a Bluetooth connection
     * @param socket  The BluetoothSocket on which the connection was made
     * @param device  The BluetoothDevice that has been connected
     */
    public synchronized void connected(BluetoothSocket socket, BluetoothDevice device) {

        // Cancel the thread that completed the connection
        if (ConnectThread != null) {ConnectThread.cancel(); ConnectThread = null;}

        // Cancel any thread currently running a connection
        if (ConnectedThread != null) {ConnectedThread.cancel(); ConnectedThread = null;}

        // Cancel the accept thread because we only want to connect to one device
 //       if (AcceptThread != null) {AcceptThread.cancel(); AcceptThread = null;}

        // Start the thread to manage the connection and perform transmissions
        ConnectedThread = new ConnectedThread(socket);
        ConnectedThread.start();

        // Send the name of the connected device back to the UI Activity
        Message msg = Handler.obtainMessage(MainActivity.MESSAGE_DEVICE_NAME);
        Bundle bundle = new Bundle();
        bundle.putString(MainActivity.DEVICE_NAME, device.getName());
        msg.setData(bundle);
        Handler.sendMessage(msg);

        setState(STATE_CONNECTED);
    }

    /**
     * Stop all threads
     */
    public synchronized void stop() {
        if (ConnectThread != null) {ConnectThread.cancel(); ConnectThread = null;}
        if (ConnectedThread != null) {ConnectedThread.cancel(); ConnectedThread = null;}
   //     if (AcceptThread != null) {AcceptThread.cancel(); AcceptThread = null;}
        setState(STATE_NONE);
    }

    /**
     * Write to the ConnectedThread in an unsynchronized manner
     * @param out The bytes to write
     * @see ConnectedThread#write(byte[])
     */
    public void write(byte[] out) {
        // Create temporary object
        ConnectedThread r;
        // Synchronize a copy of the ConnectedThread
        synchronized (this) {
            if (State != STATE_CONNECTED) return;
            r = ConnectedThread;
        }
        // Perform the write unsynchronized
         r.write(out);
    }

    /**
     * Indicate that the connection attempt failed and notify the UI Activity.
     */
    private void connectionFailed() {
        setState(STATE_LISTEN);

        // Send a failure message back to the Activity
        Message msg = Handler.obtainMessage(MainActivity.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(MainActivity.TOAST, "Unable to connect device");
        msg.setData(bundle);
        Handler.sendMessage(msg);
    }

    /**
     * Indicate that the connection was lost and notify the UI Activity.
     */
    private void connectionLost() {
        setState(STATE_LISTEN);

        // Send a failure message back to the Activity
        Message msg = Handler.obtainMessage(MainActivity.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(MainActivity.TOAST, "Device connection was lost");
        msg.setData(bundle);
        Handler.sendMessage(msg);
    }

    /**
     * This thread runs while listening for incoming connections. It behaves
     * like a server-side client. It runs until a connection is accepted
     * (or until cancelled).
     */
    /*
    private class AcceptThread extends Thread {
        // The local server socket
        private final BluetoothServerSocket ServerSocket;

        public AcceptThread() {
            BluetoothServerSocket tmp = null;

            // Create a new listening server socket
            try {
                tmp = Adapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
            } catch (IOException e) {
                }
            ServerSocket = tmp;
        }

        public void run() {
            //Looper.prepare();

            setName("AcceptThread");
            BluetoothSocket socket = null;

            // Listen to the server socket if we're not connected
            while (State != STATE_CONNECTED) {
                try {
                    // This is a blocking call and will only return on a
                    // successful connection or an exception
                    socket = ServerSocket.accept();
                } catch (IOException e) {
                     break;
                   }

                // If a connection was accepted
                if (socket != null) {
                    synchronized (BluetoothLampService.this) {
                        switch (State) {
                                        case STATE_LISTEN:
                                        case STATE_CONNECTING:
                                        // Situation normal. Start the connected thread.
                                        connected(socket, socket.getRemoteDevice());
                                        break;
                                        case STATE_NONE:
                                        case STATE_CONNECTED:
                                            // Either not ready or already connected. Terminate new socket.
                                            try {
                                                    socket.close();
                                            } catch (IOException e) {
                                                }
                            break;
                        }
                    }
                }
            }
         //   Looper.loop();
        }

        public void cancel() {
             try {
               ServerSocket.close();
            } catch (IOException e) {
             }
        }
    }
*/

    /**
     * This thread runs while attempting to make an outgoing connection
     * with a device. It runs straight through; the connection either
     * succeeds or fails.
     */
    private class ConnectThread extends Thread {
        private final BluetoothSocket Socket;
        private final BluetoothDevice Device;

        public ConnectThread(BluetoothDevice device) {
            Device = device;
            BluetoothSocket tmp = null;

            // Get a BluetoothSocket for a connection with the
            // given BluetoothDevice
            try {
                tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
            } catch (IOException e) {
             }
            Socket = tmp;
        }

        public void run() {
            Looper.prepare();
             setName("ConnectThread");

            // 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
                Socket.connect();
            } catch (IOException e) {
                connectionFailed();
                // Close the socket
                    try {
                        Socket.close();
                    } catch (IOException e2) {}

                    // Start the service over to restart listening mode
                    BluetoothLampService.this.start();
                    return;
                }

                // Reset the ConnectThread because we're done
                synchronized (BluetoothLampService.this) {
                    ConnectThread = null;
                }
                // Start the connected thread


                connected(Socket, Device);
                Looper.loop();
        }

        public void cancel() {
            try {
                Socket.close();
            } catch (IOException e) {
         }
        }
    }

    /**
     * This thread runs during a connection with a remote device.
     * It handles all incoming and outgoing transmissions.
     */
    private class ConnectedThread extends Thread {
        private final BluetoothSocket Socket;
        private final InputStream InStream;
        private final OutputStream OutStream;

        public ConnectedThread(BluetoothSocket socket) {
            Socket = socket;
            InputStream tmpIn = null;
            OutputStream tmpOut = null;

            // Get the BluetoothSocket input and output streams
            try {
                tmpIn = socket.getInputStream();
                tmpOut = socket.getOutputStream();
            } catch (IOException e) {
            }

            InStream = tmpIn;
            OutStream = tmpOut;
        }

        public void run() {
            Looper.prepare();
             byte[] buffer = new byte[1024];
             int bytes;

            // Keep listening to the InputStream while connected
            while (true) {
                try {
                    // Read from the InputStream
                    // FUNZIONANTE 
                    bytes = InStream.read(buffer);
                    Log.i("BYTES", Integer.toString(bytes));

                    //String dati = new String(buffer);
                    //fine aggiunto da me


                    // Send the obtained bytes to the UI Activity
         Handler.obtainMessage(MainActivity.MESSAGE_READ, 27, -1, buffer).sendToTarget();//buffer
                } catch (IOException e) {
                   connectionLost();
                    break;
                  }
            }
            Looper.loop();
        }

        /**
         * Write to the connected OutStream.
         * @param buffer  The bytes to write
         */
        public void write(byte[] buffer) {
            try {
                OutStream.write(buffer);

                // Share the sent message back to the UI Activity
         Handler.obtainMessage(MainActivity.MESSAGE_WRITE, -1, -1, buffer).sendToTarget();


            } catch (IOException e) {
                }
        }

        public void cancel() {
            try {
                Socket.close();
            } catch (IOException e) {
             }
        }
    }
}

Answer 1

Have you already gived permission to your android app on your Manifest file?

uses-permission android:name="android.permission.BLUETOOTH" /

uses-permission android:name="android.permission.BLUETOOTH_ADMIN" /

Then check the serial baude rate on your arduino serial connection too.

Answer 2

Kindly try by first pairing the device explicitly from your Android phone's settings. Usually the pair code is 1234