Conexión bluetooth Android con Arduino

Buenas este es el primer tutorial enlazado a mis segundo blog CursoArduinoMega.
Este tutorial consiste conectar a través de una conexión bluetooth tu dispositivo Android con el Arduino.
Vamos a enviar y recibir información.
Desde el celular Android, vamos a tener dos botones. ON OFF que van encender o apagar respectivamente
Desde el Arduino vamos a enviar 1, 2,3, 4. Ahora utilizamos estos numeros pero podría ser cualquier tipo de información como la temperatura y la humedad de un DHT11 
Todos los demás botones es puramente demostrativo que otras funcionalidades se le pueden agregar.

Fuentes: wingoodharry arduino

Configurar HC06

Comencemos con arduino

//#include "DHT.h"
//#define DHTPIN 7
//#define DHTTYPE DHT11
//DHT dht(DHTPIN, DHTTYPE);
 
int led = 13; //led Rojo de prueba de conexión

float voltageValue[4] = {0,0,0,0};
char inbyte = 0; //Char para leer el led
 
void setup() {
  // initialise serial communications at 9600 bps:
  Serial.begin(9600);
  pinMode(led, OUTPUT);
  digitalWrite(led, LOW);
  //dht.begin();
}
 
void loop() {
  getVoltageValue();
  //when serial values have been received this will be true
  
  if (Serial.available() > 0)
  {
    inbyte = Serial.read();
    Serial.println(inbyte);
    if (inbyte == '2')
    {
      digitalWrite(led, LOW); //LED off
      voltageValue[0] = 0;
    }
    if (inbyte == '1')
    {
      digitalWrite(led, HIGH); //LED on
      voltageValue[0] = 1;
    }
  }
  sendAndroidValues();
  delay(2000); 
}
 
void getVoltageValue()
{
  voltageValue[0] = 1; //led
  voltageValue[1] = 2;
  voltageValue[2] = 3;
  voltageValue[3] = 4;
  
}

//enviar los valores por el dipositivo android por el modulo Bluetooth
void sendAndroidValues()
 {
  Serial.print('#'); //hay que poner # para el comienzo de los datos, así Android sabe que empieza el String de datos
  for(int k=0; k<4; k++)
  {
    Serial.print(voltageValue[k]);
    Serial.print('+'); //separamos los datos con el +, así no es más fácil debuggear la información que enviamos
  }
 Serial.print('~'); //con esto damos a conocer la finalización del String de datos
 Serial.println();
 delay(10);        //agregamos este delay para eliminar tramisiones faltantes
}

Ahora la conexión.
Nota: En código anterior no declaramos el TX y RX (recibir e enviar información) porque vamos a usar D0 y D1. En caso contrario deberíamos declararlo como en el siguiente ejemplo (ver)

SoftwareSerial BT(10,11); //10 RX, 11 TX.

• TXD: Transmisión de datos.
• RXD: Recepción de datos a un voltaje de 3,3V.

Muestro dos opciones. Ambas funcionan.

Lo más importante, cual es muy fácil de equivocarse si uno trabajo apurado, rápido.

Es que 

• el RXD hc06 va con el TX0 del arduino
• el TXD hc06 va con el RX0 del arduino

como muestro en las imágenes

Fotos reales

Y sin mas preámbulos a los que nos interesa el código de Android

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.tatoado.ramabluewingood" >

    <uses-permission android:name="android.permission.BLUETOOTH"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".DeviceListActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".MainActivity"></activity>
    </application>

</manifest>

device_name.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textSize="18sp"
    android:padding="5dp">

</TextView>

activy_main.xml (esto tiene que estar dentro de un linearlayout o relative o como gusten, para no ser muy largo solo puse lo esencial en este layout)

 <Button
    android:id="@+id/buttonOn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="LED ON" />

<Button
    android:id="@+id/buttonOff"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="LED OFF />

<TextView
    android:id="@+id/sensorView0"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>
<TextView
    android:id="@+id/sensorView1
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>
<TextView
    android:id="@+id/sensorView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>
<TextView
    android:id="@+id/sensorView3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>

device_list.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <TextView android:id="@+id/title_paired_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Seleccione un dispositivo btSerial "
        android:visibility="gone"
        android:background="#666"
        android:textColor="#fff"
        android:paddingLeft="5dp"
    />
    <ListView android:id="@+id/paired_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:stackFromBottom="false"
        android:layout_weight="1"
    />

    <TextView
        android:id="@+id/connecting"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <TextView
        android:id="@+id/infoText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Si no hay dispositivos en la lista, por favor enlaza tu dispositivo en la configuración de Android"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:layout_margin="5dp"
        android:textSize="18dp" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center">

    </LinearLayout>

</LinearLayout>

MainActivity.java

       

            package com.tatoado.ramabluewingood;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
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.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    Button btnOn, btnOff;
    TextView txtArduino, txtString, txtStringLength, sensorView0, sensorView1, sensorView2, sensorView3;
    TextView txtSendorLDR;
    Handler bluetoothIn;

    final int handlerState = 0;             //used to identify handler message
    private BluetoothAdapter btAdapter = null;
    private BluetoothSocket btSocket = null;
    private StringBuilder recDataString = new StringBuilder();

    private ConnectedThread mConnectedThread;

    // SPP UUID service - this should work for most devices
    private static final UUID BTMODULEUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

    // String for MAC address
    private static String address = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        //Link the buttons and textViews to respective views
        btnOn = (Button) findViewById(R.id.buttonOn);
        btnOff = (Button) findViewById(R.id.buttonOff);
        txtString = (TextView) findViewById(R.id.txtString);
        txtStringLength = (TextView) findViewById(R.id.testView1);
        sensorView0 = (TextView) findViewById(R.id.sensorView0);
        sensorView1 = (TextView) findViewById(R.id.sensorView1);
        sensorView2 = (TextView) findViewById(R.id.sensorView2);
        sensorView3 = (TextView) findViewById(R.id.sensorView3);

        txtSendorLDR = (TextView) findViewById(R.id.tv_sendorldr);


        bluetoothIn = new Handler() {
            public void handleMessage(android.os.Message msg) {
                if (msg.what == handlerState) {          //if message is what we want
                    String readMessage = (String) msg.obj;                                                                // msg.arg1 = bytes from connect thread
                    recDataString.append(readMessage);              //keep appending to string until ~
                    int endOfLineIndex = recDataString.indexOf("~");                    // determine the end-of-line
                    if (endOfLineIndex > 0) {                                           // make sure there data before ~
                        String dataInPrint = recDataString.substring(0, endOfLineIndex);    // extract string
                        txtString.setText("Datos recibidos = " + dataInPrint);
                        int dataLength = dataInPrint.length();       //get length of data received
                        txtStringLength.setText("Tamaño del String = " + String.valueOf(dataLength));

                        if (recDataString.charAt(0) == '#')        //if it starts with # we know it is what we are looking for
                        {
                            String sensor0 = recDataString.substring(1, 5);             //get sensor value from string between indices 1-5
                            String sensor1 = recDataString.substring(6, 10);            //same again...
                            String sensor2 = recDataString.substring(11, 15);
                            String sensor3 = recDataString.substring(16, 20);

                            if(sensor0.equals("1.00"))
                            sensorView0.setText("Encendido"); //update the textviews with sensor values
                            else
                                sensorView0.setText("Apagado"); //update the textviews with sensor values
                            sensorView1.setText(sensor1);
                            sensorView2.setText(sensor2);
                            sensorView3.setText(sensor3);
                            //sensorView3.setText(" Sensor 3 Voltage = " + sensor3 + "V");
                        }
                        recDataString.delete(0, recDataString.length());      //clear all string data
                        // strIncom =" ";
                        dataInPrint = " ";
                    }
                }
            }
        };

        btAdapter = BluetoothAdapter.getDefaultAdapter();       // get Bluetooth adapter
        checkBTState();


        // Set up onClick listeners for buttons to send 1 or 0 to turn on/off LED
        btnOff.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                mConnectedThread.write("2");    // Send "0" via Bluetooth
                Toast.makeText(getBaseContext(), "Apagar el LED", Toast.LENGTH_SHORT).show();
            }
        });

        btnOn.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                mConnectedThread.write("1");    // Send "1" via Bluetooth
                Toast.makeText(getBaseContext(), "Encender el LED", Toast.LENGTH_SHORT).show();
            }
        });
    }


    private BluetoothSocket createBluetoothSocket(BluetoothDevice device) throws IOException {

        return  device.createRfcommSocketToServiceRecord(BTMODULEUUID);
        //creates secure outgoing connecetion with BT device using UUID
    }

    @Override
    public void onResume() {
        super.onResume();

        //Get MAC address from DeviceListActivity via intent
        Intent intent = getIntent();

        //Get the MAC address from the DeviceListActivty via EXTRA
        address = intent.getStringExtra(DeviceListActivity.EXTRA_DEVICE_ADDRESS);

        //create device and set the MAC address
        //Log.i("ramiro", "adress : " + address);
        BluetoothDevice device = btAdapter.getRemoteDevice(address);

        try {
            btSocket = createBluetoothSocket(device);
        } catch (IOException e) {
            Toast.makeText(getBaseContext(), "La creacción del Socket fallo", Toast.LENGTH_LONG).show();
        }
        // Establish the Bluetooth socket connection.
        try
        {
            btSocket.connect();
        } catch (IOException e) {
            try
            {
                btSocket.close();
            } catch (IOException e2)
            {
                //insert code to deal with this
            }
        }
        mConnectedThread = new ConnectedThread(btSocket);
        mConnectedThread.start();

        //I send a character when resuming.beginning transmission to check device is connected
        //If it is not an exception will be thrown in the write method and finish() will be called
        mConnectedThread.write("x");
    }

    @Override
    public void onPause()
    {
        super.onPause();
        try
        {
            //Don't leave Bluetooth sockets open when leaving activity
            btSocket.close();
        } catch (IOException e2) {
            //insert code to deal with this
        }
    }

    //Checks that the Android device Bluetooth is available and prompts to be turned on if off
    private void checkBTState() {

        if(btAdapter==null) {
            Toast.makeText(getBaseContext(), "El dispositivo no soporta bluetooth", Toast.LENGTH_LONG).show();
        } else {
            if (btAdapter.isEnabled()) {
            } else {
                Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
                startActivityForResult(enableBtIntent, 1);
            }
        }
    }

    //create new class for connect thread
    private class ConnectedThread extends Thread {
        private final InputStream mmInStream;
        private final OutputStream mmOutStream;

        //creation of the connect thread
        public ConnectedThread(BluetoothSocket socket) {
            InputStream tmpIn = null;
            OutputStream tmpOut = null;

            try {
                //Create I/O streams for connection
                tmpIn = socket.getInputStream();
                tmpOut = socket.getOutputStream();
            } catch (IOException e) { }

            mmInStream = tmpIn;
            mmOutStream = tmpOut;
        }


        public void run() {
            byte[] buffer = new byte[256];
            int bytes;

            // Keep looping to listen for received messages
            while (true) {
                try {
                    bytes = mmInStream.read(buffer);         //read bytes from input buffer
                    String readMessage = new String(buffer, 0, bytes);
                    // Send the obtained bytes to the UI Activity via handler
                    bluetoothIn.obtainMessage(handlerState, bytes, -1, readMessage).sendToTarget();
                } catch (IOException e) {
                    break;
                }
            }
        }
        //write method
        public void write(String input) {
            byte[] msgBuffer = input.getBytes();           //converts entered String into bytes
            try {
                mmOutStream.write(msgBuffer);                //write bytes over BT connection via outstream
            } catch (IOException e) {
                //if you cannot write, close the application
                Toast.makeText(getBaseContext(), "La Conexión fallo", Toast.LENGTH_LONG).show();
                finish();

            }
        }
    }
}

DeviceListActivity.java

       

            package com.tatoado.ramabluewingood;

import java.util.Set;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;


public class DeviceListActivity extends Activity {
    // Debugging for LOGCAT
    private static final String TAG = "DeviceListActivity";
    private static final boolean D = true;
    
  
    // declare button for launching website and textview for connection status
    Button tlbutton;
    TextView textView1;
    
    // EXTRA string to send on to mainactivity
    public static String EXTRA_DEVICE_ADDRESS = "device_address";

    // Member fields
    private BluetoothAdapter mBtAdapter;
    private ArrayAdapter mPairedDevicesArrayAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.device_list);
    }
    
    @Override
    public void onResume() 
    {
     super.onResume();
     //*************** 
     checkBTState();

     textView1 = (TextView) findViewById(R.id.connecting);
     textView1.setTextSize(40);
     textView1.setText(" ");

     // Initialize array adapter for paired devices
     mPairedDevicesArrayAdapter = new ArrayAdapter(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);

     // Get the local Bluetooth adapter
     mBtAdapter = BluetoothAdapter.getDefaultAdapter();

     // Get a set of currently paired devices and append to 'pairedDevices'
     Set pairedDevices = mBtAdapter.getBondedDevices();

     // Add previosuly paired devices to the array
     if (pairedDevices.size() > 0) {
      findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);//make title viewable
      for (BluetoothDevice device : pairedDevices) {
       mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
      }
     } else {
      String noDevices = "Ningun dispositivo pudo ser emparejado";
      mPairedDevicesArrayAdapter.add(noDevices);
     }
  }

    // Set up on-click listener for the list (nicked this - unsure)
    private OnItemClickListener mDeviceClickListener = new OnItemClickListener() {
        public void onItemClick(AdapterView av, View v, int arg2, long arg3) {

         textView1.setText("Conectando...");
            // 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);

            // Make an intent to start next activity while taking an extra which is the MAC address.
   Intent i = new Intent(DeviceListActivity.this, MainActivity.class);
            i.putExtra(EXTRA_DEVICE_ADDRESS, address);
   startActivity(i);   
        }
    };

    private void checkBTState() {
        // Check device has Bluetooth and that it is turned on
      mBtAdapter=BluetoothAdapter.getDefaultAdapter(); // CHECK THIS OUT THAT IT WORKS!!!
        if(mBtAdapter==null) { 
         Toast.makeText(getBaseContext(), "El dispositivo no soporta Bluetooth", Toast.LENGTH_SHORT).show();
        } else {
          if (mBtAdapter.isEnabled()) {
            Log.d(TAG, "...Bluetooth Activado...");
          } else {
            //Prompt user to turn on Bluetooth
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBtIntent, 1);
 
            }
          }
        }
}