I am creating an Android app that allows me to control a device connected to Arduino using Bluetooth, with Android 4.4.2, Arduino Uno and HC-05 Module.
Right now I'm finding serious difficulties to print data in the Arduino serial (in order to verify if it's really working). I tried everything I have found in this or other forums related to this topic.
For the moment, I have been able to detect the devices, pair with them and create the Socket and the OutputStream, but for some reason the data doesn't show up.
The code is 2 basic Activities and their layouts (Android) and the Arduino code:
Image of how it shows the available devices.
Image of how now that device is paired with our Android Device.
GetPaired.java:
Basically gets the available devices, show them in a custom ListView, allows you to pair/unpair with them and after you get the device paired, you go to the ConnectionControl activity.
import java.lang.reflect.Method;
import java.util.ArrayList;
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.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Toast;
public class GetPaired extends Activity {
ListView listViewPaired;
ListView listViewDetected;
ArrayList<String> arrayListpaired;
Button buttonSearch,buttonControl;
ArrayAdapter<String> adapter, detectedAdapter;
BluetoothDevice bdDevice;
ArrayList<BluetoothDevice> arrayListPairedBluetoothDevices;
ListItemClickedonPaired listItemClickedonPaired;
BluetoothAdapter bluetoothAdapter = null;
ArrayList<BluetoothDevice> arrayListBluetoothDevices = null;
ListItemClicked listItemClicked;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bluetooth_demo);
listViewDetected = (ListView)
findViewById(R.id.listViewDetected);
listViewPaired = (ListView) findViewById(R.id.listViewPaired);
buttonSearch = (Button) findViewById(R.id.buttonSearch);
buttonControl = (Button) findViewById(R.id.buttonControl);
arrayListpaired = new ArrayList<String>();
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
arrayListPairedBluetoothDevices = new ArrayList<BluetoothDevice();
listItemClickedonPaired = new ListItemClickedonPaired();
arrayListBluetoothDevices = new ArrayList<BluetoothDevice>();
adapter = new ArrayAdapter<String>(GetPaired.this,
R.layout.custom_layout, arrayListpaired);
detectedAdapter = new ArrayAdapter<String>(GetPaired.this,
R.layout.custom_layout);
listViewDetected.setAdapter(detectedAdapter);
listItemClicked = new ListItemClicked();
detectedAdapter.notifyDataSetChanged();
listViewPaired.setAdapter(adapter);
}
@Override
protected void onStart() {
// TODO Auto-generated method stub
super.onStart();
//Get all the paired bluetooth devices with Android.
getPairedDevices();
listViewDetected.setOnItemClickListener(listItemClicked);
listViewPaired.setOnItemClickListener(listItemClickedonPaired);
}
private void getPairedDevices() {
Set<BluetoothDevice> pairedDevice =
bluetoothAdapter.getBondedDevices();
if (pairedDevice.size() > 0) {
for (BluetoothDevice device : pairedDevice) {
arrayListpaired.add(device.getName() + "\n" +
device.getAddress());
arrayListPairedBluetoothDevices.add(device);
break;
}
}
adapter.notifyDataSetChanged();
}
//When clicked a bluetooth device from the available list, a bond is
created between them.
class ListItemClicked implements OnItemClickListener{
@Override
public void onItemClick(AdapterView<?> parent, View view, int
position, long id) {
// TODO Auto-generated method stub
bdDevice = arrayListBluetoothDevices.get(position);
Log.i("Log", "The device : " + bdDevice.toString());
Boolean isBonded = false;
try {
isBonded = createBond(bdDevice);
if (isBonded) {
getPairedDevices();
adapter.notifyDataSetChanged();
Log.i("Log", "The bond is created: " + isBonded);
}
} catch (Exception e) {
e.printStackTrace();
}
connect(bdDevice);
}
}
//When clicked in the list of paired devices, you remove the bond and
the pairing.
class ListItemClickedonPaired implements OnItemClickListener{
@Override
public void onItemClick(AdapterView<?> parent, View view, int
position, long id) {
bdDevice = arrayListPairedBluetoothDevices.get(position);
try {
Boolean removeBonding = removeBond(bdDevice);
if (removeBonding) {
arrayListpaired.remove(position);
adapter.notifyDataSetChanged();
}
Log.i("Log", "Removed" + removeBonding);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private Boolean connect(BluetoothDevice bdDevice) {
Boolean bool = false;
try {
Log.i("Log", "service method is called ");
Class cl = Class.forName("android.bluetooth.BluetoothDevice");
Class[] par = {};
Method method = cl.getMethod("createBond", par);
bool = (Boolean) method.invoke(bdDevice);
} catch (Exception e) {
Log.i("Log", "Inside catch of serviceFromDevice Method");
e.printStackTrace();
}
return bool.booleanValue();
}
public boolean removeBond(BluetoothDevice btDevice)
throws Exception {
Class btClass =
Class.forName("android.bluetooth.BluetoothDevice");
Method removeBondMethod = btClass.getMethod("removeBond");
Boolean returnValue = (Boolean) removeBondMethod.invoke(btDevice);
return returnValue.booleanValue();
}
public boolean createBond(BluetoothDevice btDevice)
throws Exception {
Class class1 = Class.forName("android.bluetooth.BluetoothDevice");
Method createBondMethod = class1.getMethod("createBond");
Boolean returnValue = (Boolean) createBondMethod.invoke(btDevice);
return returnValue.booleanValue();
}
//Searches for available bluetooth devices to add them to the
Detected
List.
private BroadcastReceiver myReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
Toast.makeText(context, "ACTION_FOUND",
Toast.LENGTH_SHORT).show();
BluetoothDevice device =
intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
if (arrayListBluetoothDevices.size() < 1) // this checks
if the size of bluetooth device is 0,then add the
{ // device to
the arraylist.
detectedAdapter.add(device.getName() + "\n" +
device.getAddress());
arrayListBluetoothDevices.add(device);
detectedAdapter.notifyDataSetChanged();
} else {
boolean flag = true; // flag to indicate that
particular device is already in the arlist or not
for (byte i = 0; i < arrayListBluetoothDevices.size();
i++) {
if
(device.getAddress().equals(arrayListBluetoothDevices.get(i).getAddress())
) {
flag = false;
}
}
if (flag == true) {
detectedAdapter.add(device.getName() + "\n" +
device.getAddress());
arrayListBluetoothDevices.add(device);
detectedAdapter.notifyDataSetChanged();
}
}
}
}
};
//Method that starts the search of bluetooth devices to connect with.
public void startSearching(View v) {
arrayListBluetoothDevices.clear();
Log.i("Log", "in the start searching method");
IntentFilter intentFilter = new
IntentFilter(BluetoothDevice.ACTION_FOUND);
GetPaired.this.registerReceiver(myReceiver, intentFilter);
bluetoothAdapter.startDiscovery();
}
//When you have the device paired with Android, you can go to the
next
Activity, where the proper connection is stablished.
public void onControl(View v) {
if (arrayListPairedBluetoothDevices.size() > 0) {
Log.i("Log", "There is a paired device.");
Intent sipoptent = new Intent(getApplicationContext(),
ConnectionControl.class).putExtra("Bluetooth",
arrayListPairedBluetoothDevices.get(0));
startActivity(sipoptent);
if (arrayListPairedBluetoothDevices.get(0) != null) {
} else {
}
} else {
Log.i("Log", "Not paired to a device yet.");
Toast.makeText(GetPaired.this, "Not paired to a device
yet.",
Toast.LENGTH_SHORT).show();
}
}
}
The ConnectionControl Activity:
Receives an intent with a BluetoothDevice Object, as the device we are going to connect with. Creates the BluetoothSocket, the connection Thread the OutputStream.
*In this part of the code I tried to get another UUID, but again couldn't find anything.
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import java.io.IOException;
import java.util.UUID;
import java.io.OutputStream;
public class ConnectionControl extends AppCompatActivity {
Button on, off;
private BluetoothSocket btSocket = null;
private BluetoothDevice device;
private OutputStream mmOutStream =null;
// SPP UUID service - this should work for most devices
private static final UUID BTMODULEUUID = UUID.fromString("00001101-
0000-1000-8000-00805F9B34FB");
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
on = (Button) findViewById(R.id.onbutton);
off = (Button) findViewById(R.id.offbutton);
device = getIntent().getExtras().getParcelable("Bluetooth");
//Bluetooth device information retrieved by an Intent.
Toast.makeText(ConnectionControl.this, device.getAddress(),
Toast.LENGTH_SHORT).show();
}
@Override
public void onResume() {
super.onResume();
try {
//Creation of the socket of the connection.
btSocket = createBluetoothSocket(device);
} catch (IOException e) {
Toast.makeText(getBaseContext(),"Socket connection failed.",
Toast.LENGTH_LONG).show();
}
// Establish the Bluetooth socket connection.
try {
btSocket.connect();
ConnectedThread(btSocket);
write("x");
} catch (IOException e) {
try {
btSocket.close();
} catch (IOException e2) {}
}
}
//Creates secure outgoing connecetion with BT device using UUID
private BluetoothSocket createBluetoothSocket(BluetoothDevice device)
throws IOException {
return device.createRfcommSocketToServiceRecord(BTMODULEUUID);
}
//Creates the OutputStream from the socket.
public void ConnectedThread(BluetoothSocket socket) {
OutputStream tmpOut = null;
try {
tmpOut = socket.getOutputStream();
} catch (IOException e) {
Toast.makeText(getBaseContext(), "Connection Not
Established.", Toast.LENGTH_LONG).show();
}
Toast.makeText(getBaseContext(), "Connection Established.", Toast.LENGTH_LONG).show();
mmOutStream = tmpOut;
}
@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
}
}
//Transforms a String input into an array of bytes to send to the bluetooth device.
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(), "Conection failed.", Toast.LENGTH_LONG).show();
}
}
public void onON(View view){
write("0");
}
public void onOFF(View view){
write("1");
}
}
And the Arduino code:
In the Arduino hardware I connected the 5V and already entered in AT mode to the Bluetooth to change its name before.
#include <SoftwareSerial.h>
SoftwareSerial mySerial(10, 11); // RX, TX
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
// set the data rate for the SoftwareSerial port
mySerial.begin(9600);
}
void loop() { // run over and over
if (mySerial.available()) {
Serial.write(mySerial.read());
}
if (Serial.available()) {
mySerial.write(Serial.read());
}
}
What can I try next?
