Sending serial data from Arduino to Android via Bluetooth - NOT ANSWERED Yet

Question

Hi all,

I've been working on my Arduino project for quite a while now, managed to process the incoming data in the Arduino and display it on LCD (data is coming from a simulation on the laptop). But I cannot manage to view this data on my Android App (used MIT App Inventor) via Bluetooth (HC-06). I have managed to do this but after a week I tested it again and found some errors (I think problem was with my hardware) therefore (silly me) I didnt save the sketch, therefore blocks in MIT App Inventor are 100% working.

Also, I am connecting RX pin of Bluetooth through a voltage divider with pin 7. Any ideas pls?

Arduino sketch:

#include <SoftwareSerial.h>

#include <LiquidCrystal.h>

byte myByte; // Storing the incoming data from serial port

int txPin = 7;

int rxPin =6;

lcd(12,11,5,4,3,2) //pin of lcd ****I know this is not the exact command

SoftwareSerial BlueToothConnect(txPin, rxPin);

pinMode(rxPin, INPUT);

pinMode(txPin, OUTPUT);

void setup(){

lcd.begin(16,2);

Serial.begin(9600); //Serial communication

}

void loop(){

if(Serial.available(){

lcd.clear();

while(Serial.available()>0){ //Until data is being found in Serial, turn on serial on Bluetooth

BlueToothConnect.begin(9600);

myByte = Serial.read(); //reading the myByte data

lcd.write(myByte); //showing data on LCD

Serial.write(myByte) ; //Showing data on serial monitor

txPin = digitalWrite(myByte); //writing myByte content on pin 7 (txPin)

BlueToothConnect.write(txPin); // BlueToothConnect.print(txPin); //displaying content of txPin to be view on Android display

}

Message was edited by: Lor B

neilk · Accepted Answer

Hi lorrainebarbara I've never used SoftwareSerial successfully, although I've been trying to recently to reprogram an HC05 (Master/Slave Bluetooth). This requires the use of SoftWare serial ad so far I haven't got anybody else's sketches to work!! So I decided to make a very simple example; it works, and here it is: /* Demonstration of sending data to an Android App via Bluetooth. This example
 uses SoftwareSerial on pins 2 and 3
 
 Characters are read in from the keyboard, output on the Serial Monitor and written to
 the Bluetooth device using SoftwareSerial
 
 Neil Kenyon
 05 June 2015 
*/
 
#include <SoftwareSerial.h>`

#define rxPin 2 // define SoftwareSerial rx data pin
#define txPin 3 // define SoftwareSerial tx data pin

SoftwareSerial blueTooth(rxPin, txPin); // create instance of SoftwareSerial

void setup()
{
 Serial.begin(9600); // Start hardware Serial
 blueTooth.begin(9600); // Start SoftwareSerial
}

void loop()
{
 char c;
 if (Serial.available())
 {
 c = Serial.read();
 
 Serial.println(c); // Write the character to the Serial Monitor
 
 blueTooth.write (c); // Write the character to Bluetooth
 }
} It actually works with the very simple Android app given in my blog. Hope you can get it working Neil

gadget.iom · Answer

Are you trying to send sensor values or text typed into the serial monitor?

All of the other references to bluetooth.print are commented out.

Try putting:

bluetooth.print("Sending Init String"); // Test bluetooth TX

after the line:

bluetooth.begin(9600);  // Start bluetooth serial at 9600

and see if you get any output when you reset the Arduino.

Former Member · Answer

Hi neilk , Thank you so much I have managed to incorporate (and change) some of the program you ve published, worked Here is my whole sketch. Thanks alot for your help!! //Sending data serially to Android via Bluetooth from Arduino #include //Libary used for Software Serial (Using other pins instead of 0 and 1) //Since pin 0 and pin 1 are being used by the Arduino USB cable #include //Library used for LCD LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //Initilizing Arduino pins #define rxPin 8 // define SoftwareSerial rx data pin on pin8 #define txPin 9 // define SoftwareSerial tx data pin on pin9 int potPin = 0; // Define the Analog input SoftwareSerial blueTooth(rxPin, txPin); // create instance of SoftwareSerial(8, 9 respectively) void setup() { lcd.begin(16, 2); //Setting up LCD columns and rows Serial.begin(9600); // Start hardware Serial pinMode(potPin, INPUT); blueTooth.begin(9600); // Start SoftwareSerial } void loop() { byte incomingData; //incoming data if (Serial.available()) //If there is data in serial port { delay(100); //Delay of 100ms lcd.clear(); //Clear the LCD display while(Serial.available()>0) { incomingData = Serial.read();//read the values in 'incomingData' lcd.write(incomingData); // ASCII character printed on LCD Serial.write(incomingData); //Write the characters on the Serial Monitor //Serial.println(incomingData); // Write the characters to the Serial Monitor blueTooth.write(incomingData); // Write the characters to Bluetooth } } }

neilk · Answer

lorrainebarbara Hi If you have HC06, then it should already be in Slave mode and 9600 Baud by default. - shouldn't need AT commands at this stage I use a voltage divider between the Arduino Tx and HC06 Rx Have you paired the HC06 with your Android device? If you had it working, it may have become unpaired 
 txPin = digitalWrite(myByte); //writing myByte content on pin 7 (txPin) 
 BlueToothConnect.write(txPin); // BlueToothConnect.print(txPin); //displaying content of txPin to be view on Android display 
 Seems a bit confused - why are you trying to output to the software serial Tx pin with a digital Write? Finally, can I suggest you go back to basics and prove that you can send data to your Android device, via Bluetooth, using the Arduino hardware Rx/Tx pins, as shown in my blog: http://www.element14.com/community/people/neilk/blog/2014/07/18/app-inventor-and-arduino-part-2--send-data-from-arduino-to-android-app Using your own Android App, of course. Hope this helps Neil

happyforever · Answer

Thanks for reply my answer, but i try add the [ bluetooth.print( "Sending Init String" ); ] but the error still there. Besides that, serial monitor also do not display this message. Is because android part got problem? Below is my android code(MainActivity.java) package com.example.helloworld.ninjatechsmartheadphone ; import java.io.IOException ; import java.io.InputStream ; import java.io.OutputStream ; import java.lang.reflect.Method ; import java.util.UUID ; import android.support.v7.app.AppCompatActivity ; 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.TextView ; import android.media.MediaPlayer ; import android.widget.Toast ; public class MainActivity extends AppCompatActivity { private static final String TAG = "bluetooth" ; Button on ; Button off ; Button button ; TextView txtArduino ; Handler h ; final int RECIEVE_MESSAGE = 1 ; // Status for Handler private BluetoothAdapter btAdapter = null; private BluetoothSocket btSocket = null; private StringBuilder sb = new StringBuilder() ; private ConnectedThread mConnectedThread ; // SPP UUID service private static final UUID MY_UUID = UUID. fromString ( "00001101-0000-1000-8000-00805F9B34FB" ) ; private static String address = "98:D3:31:FD:21:00" ; @Override public void onCreate (Bundle savedInstanceState) { super .onCreate(savedInstanceState) ; setContentView(R.layout. activity_main ) ; final MediaPlayer catSoundMediaPlayer = MediaPlayer. create ( this, R.raw. afi ) ; button = (Button) findViewById(R.id. play ) ; on = (Button) findViewById(R.id. on ) ; off = (Button) findViewById(R.id. off ) ; txtArduino = (TextView) findViewById(R.id. txtArduino ) ; // for display the received data from the Arduino h = new Handler() { public void handleMessage (android.os.Message msg) { Log. d ( "msg" , "msg.what is " + msg. what ) ; switch (msg. what ) { case RECIEVE_MESSAGE : // if receive massage byte [] readBuf = ( byte []) msg. obj ; Toast. makeText (getBaseContext() , "I want try try try" , Toast. LENGTH_SHORT ).show() ; String strIncom = new String(readBuf , 0 , msg. arg1 ) ; // create string from bytes array sb .append(strIncom) ; // append string int endOfLineIndex = sb .indexOf( " 
 " ) ; // determine the end-of-line if (endOfLineIndex > 0 ) { // if end-of-line, String sbprint = sb .substring( 0 , endOfLineIndex) ; // extract string sb .delete( 0 , sb .length()) ; // and clear txtArduino .setText( "Data from Arduino: " + sbprint) ; // update TextView //off.setEnabled(true); // on.setEnabled(true); } Log. d ( TAG , "...String:" + sb .toString() + "Byte:" + msg. arg1 + "..." ) ; break; default : Toast. makeText (getBaseContext() , "I want try" , Toast. LENGTH_LONG ).show() ; Log. d ( TAG , "...String:" + sb .toString() + "Byte:" + msg. arg1 + "..." ) ; } } ; } ; btAdapter = BluetoothAdapter. getDefaultAdapter () ; // get Bluetooth adapter checkBTState() ; button .setOnClickListener( new OnClickListener() { public void onClick (View v) { catSoundMediaPlayer .start() ; //Intent intent = new Intent("android.intent.action.MUSIC_PLAYER"); //intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); //startActivity(intent); } }) ; on .setOnClickListener( new OnClickListener() { public void onClick (View v) { //on.setEnabled(false); mConnectedThread .write( "1" ) ; // Send "1" via Bluetooth Toast. makeText (getBaseContext() , "Turn on Alert Signal" , Toast. LENGTH_SHORT ).show() ; } }) ; off .setOnClickListener( new OnClickListener() { public void onClick (View v) { //off.setEnabled(false); mConnectedThread .write( "0" ) ; // Send "0" via Bluetooth Toast. makeText (getBaseContext() , "Turn off Alert Signal" , Toast. LENGTH_SHORT ).show() ; } }) ; } private BluetoothSocket createBluetoothSocket (BluetoothDevice device) throws IOException { try { final Method m = device.getClass().getMethod( "createInsecureRfcommSocketToServiceRecord" , new Class[] { UUID. class }) ; return (BluetoothSocket) m.invoke(device , MY_UUID ) ; } catch (Exception e) { Log. e ( TAG , "Could not create Insecure RFComm Connection" , e) ; } return device.createRfcommSocketToServiceRecord( MY_UUID ) ; } @Override public void onResume () { super .onResume() ; Log. d ( TAG , "...onResume - try connect..." ) ; // Set up a pointer to the remote node using it's address. BluetoothDevice device = btAdapter .getRemoteDevice( address ) ; // Two things are needed to make a connection: // A MAC address, which we got above. // A Service ID or UUID. In this case we are using the // UUID for SPP. try { btSocket = createBluetoothSocket(device) ; } catch (IOException e) { errorExit( "Fatal Error" , "In onResume() and socket create failed: " + e.getMessage() + "." ) ; } // Discovery is resource intensive. Make sure it isn't going on // when you attempt to connect and pass your message. btAdapter .cancelDiscovery() ; // Establish the connection. This will block until it connects. Log. d ( TAG , "...Connecting..." ) ; try { btSocket .connect() ; Log. d ( TAG , "....Connection ok..." ) ; Toast. makeText (getBaseContext() , "Connected" , Toast. LENGTH_SHORT ).show() ; } catch (IOException e) { try { //Log.d(TAG, "....111..."); //Toast.makeText(getBaseContext(), "1", Toast.LENGTH_SHORT).show(); btSocket .close() ; } catch (IOException e2) { errorExit( "Fatal Error" , "In onResume() and unable to close socket during connection failure" + e2.getMessage() + "." ) ; //Toast.makeText(getBaseContext(), "2", Toast.LENGTH_SHORT).show(); } } // Create a data stream so we can talk to server. Log. d ( TAG , "...Create Socket..." ) ; mConnectedThread = new ConnectedThread( btSocket ) ; mConnectedThread .start() ; } @Override public void onPause () { super .onPause() ; Log. d ( TAG , "...In onPause()..." ) ; try { btSocket .close() ; } catch (IOException e2) { errorExit( "Fatal Error" , "In onPause() and failed to close socket." + e2.getMessage() + "." ) ; } } private void checkBTState () { // Check for Bluetooth support and then check to make sure it is turned on // Emulator doesn't support Bluetooth and will return null if ( btAdapter == null ) { errorExit( "Fatal Error" , "Bluetooth not support" ) ; } else { if ( btAdapter .isEnabled()) { Log. d ( TAG , "...Bluetooth ON..." ) ; } else { //Prompt user to turn on Bluetooth Intent enableBtIntent = new Intent(BluetoothAdapter. ACTION_REQUEST_ENABLE ) ; startActivityForResult(enableBtIntent , 1 ) ; } } } private void errorExit (String title , String message){ Toast. makeText (getBaseContext() , title + " - " + message , Toast. LENGTH_LONG ).show() ; finish() ; } private class ConnectedThread extends Thread { private final InputStream mmInStream ; private final OutputStream mmOutStream ; public ConnectedThread (BluetoothSocket socket) { InputStream tmpIn = null; OutputStream tmpOut = null; // Get the input and output streams, using temp objects because // member streams are final try { tmpIn = socket.getInputStream() ; tmpOut = socket.getOutputStream() ; } catch (IOException e) { } mmInStream = tmpIn ; mmOutStream = tmpOut ; } public void run () { byte [] buffer = new byte [ 256 ] ; // buffer store for the stream int bytes ; // bytes returned from read() //Toast.makeText(getBaseContext(), "qqqqqqq", Toast.LENGTH_SHORT).show(); // Keep listening to the InputStream until an exception occurs while ( true ) { try { // Read from the InputStream bytes = mmInStream .read(buffer) ; // Get number of bytes and message in "buffer" h .obtainMessage( RECIEVE_MESSAGE , bytes , - 1 , buffer).sendToTarget() ; // Send to message queue Handler Toast. makeText (getBaseContext() , "q111q" , Toast. LENGTH_SHORT ).show() ; } catch (IOException e) { //Toast.makeText(getBaseContext(), "qq222qq", Toast.LENGTH_SHORT).show(); break; } } } /* Call this from the main activity to send data to the remote device */ public void write (String message) { Log. d ( TAG , "...Data to send: " + message + "..." ) ; byte [] msgBuffer = message.getBytes() ; try { mmOutStream .write(msgBuffer) ; } catch (IOException e) { Log. d ( TAG , "...Error data send: " + e.getMessage() + "..." ) ; } } } }

happyforever · Answer

Hi Neil, can you help me check my android code got any problem? I think maybe is android part cause this error. Below is my android code(MainActivity.java) package com.example.helloworld.ninjatechsmartheadphone ; import java.io.IOException ; import java.io.InputStream ; import java.io.OutputStream ; import java.lang.reflect.Method ; import java.util.UUID ; import android.support.v7.app.AppCompatActivity ; 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.TextView ; import android.media.MediaPlayer ; import android.widget.Toast ; public class MainActivity extends AppCompatActivity { private static final String TAG = "bluetooth" ; Button on ; Button off ; Button button ; TextView txtArduino ; Handler h ; final int RECIEVE_MESSAGE = 1 ; // Status for Handler private BluetoothAdapter btAdapter = null; private BluetoothSocket btSocket = null; private StringBuilder sb = new StringBuilder() ; private ConnectedThread mConnectedThread ; // SPP UUID service private static final UUID MY_UUID = UUID. fromString ( "00001101-0000-1000-8000-00805F9B34FB" ) ; private static String address = "98:D3:31:FD:21:00" ; @Override public void onCreate (Bundle savedInstanceState) { super .onCreate(savedInstanceState) ; setContentView(R.layout. activity_main ) ; final MediaPlayer catSoundMediaPlayer = MediaPlayer. create ( this, R.raw. afi ) ; button = (Button) findViewById(R.id. play ) ; on = (Button) findViewById(R.id. on ) ; off = (Button) findViewById(R.id. off ) ; txtArduino = (TextView) findViewById(R.id. txtArduino ) ; // for display the received data from the Arduino h = new Handler() { public void handleMessage (android.os.Message msg) { Log. d ( "msg" , "msg.what is " + msg. what ) ; switch (msg. what ) { case RECIEVE_MESSAGE : // if receive massage byte [] readBuf = ( byte []) msg. obj ; Toast. makeText (getBaseContext() , "I want try try try" , Toast. LENGTH_SHORT ).show() ; String strIncom = new String(readBuf , 0 , msg. arg1 ) ; // create string from bytes array sb .append(strIncom) ; // append string int endOfLineIndex = sb .indexOf( " 
 " ) ; // determine the end-of-line if (endOfLineIndex > 0 ) { // if end-of-line, String sbprint = sb .substring( 0 , endOfLineIndex) ; // extract string sb .delete( 0 , sb .length()) ; // and clear txtArduino .setText( "Data from Arduino: " + sbprint) ; // update TextView //off.setEnabled(true); // on.setEnabled(true); } Log. d ( TAG , "...String:" + sb .toString() + "Byte:" + msg. arg1 + "..." ) ; break; default : Toast. makeText (getBaseContext() , "I want try" , Toast. LENGTH_LONG ).show() ; Log. d ( TAG , "...String:" + sb .toString() + "Byte:" + msg. arg1 + "..." ) ; } } ; } ; btAdapter = BluetoothAdapter. getDefaultAdapter () ; // get Bluetooth adapter checkBTState() ; button .setOnClickListener( new OnClickListener() { public void onClick (View v) { catSoundMediaPlayer .start() ; //Intent intent = new Intent("android.intent.action.MUSIC_PLAYER"); //intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); //startActivity(intent); } }) ; on .setOnClickListener( new OnClickListener() { public void onClick (View v) { //on.setEnabled(false); mConnectedThread .write( "1" ) ; // Send "1" via Bluetooth Toast. makeText (getBaseContext() , "Turn on Alert Signal" , Toast. LENGTH_SHORT ).show() ; } }) ; off .setOnClickListener( new OnClickListener() { public void onClick (View v) { //off.setEnabled(false); mConnectedThread .write( "0" ) ; // Send "0" via Bluetooth Toast. makeText (getBaseContext() , "Turn off Alert Signal" , Toast. LENGTH_SHORT ).show() ; } }) ; } private BluetoothSocket createBluetoothSocket (BluetoothDevice device) throws IOException { try { final Method m = device.getClass().getMethod( "createInsecureRfcommSocketToServiceRecord" , new Class[] { UUID. class }) ; return (BluetoothSocket) m.invoke(device , MY_UUID ) ; } catch (Exception e) { Log. e ( TAG , "Could not create Insecure RFComm Connection" , e) ; } return device.createRfcommSocketToServiceRecord( MY_UUID ) ; } @Override public void onResume () { super .onResume() ; Log. d ( TAG , "...onResume - try connect..." ) ; // Set up a pointer to the remote node using it's address. BluetoothDevice device = btAdapter .getRemoteDevice( address ) ; // Two things are needed to make a connection: // A MAC address, which we got above. // A Service ID or UUID. In this case we are using the // UUID for SPP. try { btSocket = createBluetoothSocket(device) ; } catch (IOException e) { errorExit( "Fatal Error" , "In onResume() and socket create failed: " + e.getMessage() + "." ) ; } // Discovery is resource intensive. Make sure it isn't going on // when you attempt to connect and pass your message. btAdapter .cancelDiscovery() ; // Establish the connection. This will block until it connects. Log. d ( TAG , "...Connecting..." ) ; try { btSocket .connect() ; Log. d ( TAG , "....Connection ok..." ) ; Toast. makeText (getBaseContext() , "Connected" , Toast. LENGTH_SHORT ).show() ; } catch (IOException e) { try { //Log.d(TAG, "....111..."); //Toast.makeText(getBaseContext(), "1", Toast.LENGTH_SHORT).show(); btSocket .close() ; } catch (IOException e2) { errorExit( "Fatal Error" , "In onResume() and unable to close socket during connection failure" + e2.getMessage() + "." ) ; //Toast.makeText(getBaseContext(), "2", Toast.LENGTH_SHORT).show(); } } // Create a data stream so we can talk to server. Log. d ( TAG , "...Create Socket..." ) ; mConnectedThread = new ConnectedThread( btSocket ) ; mConnectedThread .start() ; } @Override public void onPause () { super .onPause() ; Log. d ( TAG , "...In onPause()..." ) ; try { btSocket .close() ; } catch (IOException e2) { errorExit( "Fatal Error" , "In onPause() and failed to close socket." + e2.getMessage() + "." ) ; } } private void checkBTState () { // Check for Bluetooth support and then check to make sure it is turned on // Emulator doesn't support Bluetooth and will return null if ( btAdapter == null ) { errorExit( "Fatal Error" , "Bluetooth not support" ) ; } else { if ( btAdapter .isEnabled()) { Log. d ( TAG , "...Bluetooth ON..." ) ; } else { //Prompt user to turn on Bluetooth Intent enableBtIntent = new Intent(BluetoothAdapter. ACTION_REQUEST_ENABLE ) ; startActivityForResult(enableBtIntent , 1 ) ; } } } private void errorExit (String title , String message){ Toast. makeText (getBaseContext() , title + " - " + message , Toast. LENGTH_LONG ).show() ; finish() ; } private class ConnectedThread extends Thread { private final InputStream mmInStream ; private final OutputStream mmOutStream ; public ConnectedThread (BluetoothSocket socket) { InputStream tmpIn = null; OutputStream tmpOut = null; // Get the input and output streams, using temp objects because // member streams are final try { tmpIn = socket.getInputStream() ; tmpOut = socket.getOutputStream() ; } catch (IOException e) { } mmInStream = tmpIn ; mmOutStream = tmpOut ; } public void run () { byte [] buffer = new byte [ 256 ] ; // buffer store for the stream int bytes ; // bytes returned from read() //Toast.makeText(getBaseContext(), "qqqqqqq", Toast.LENGTH_SHORT).show(); // Keep listening to the InputStream until an exception occurs while ( true ) { try { // Read from the InputStream bytes = mmInStream .read(buffer) ; // Get number of bytes and message in "buffer" h .obtainMessage( RECIEVE_MESSAGE , bytes , - 1 , buffer).sendToTarget() ; // Send to message queue Handler Toast. makeText (getBaseContext() , "q111q" , Toast. LENGTH_SHORT ).show() ; } catch (IOException e) { //Toast.makeText(getBaseContext(), "qq222qq", Toast.LENGTH_SHORT).show(); break; } } } /* Call this from the main activity to send data to the remote device */ public void write (String message) { Log. d ( TAG , "...Data to send: " + message + "..." ) ; byte [] msgBuffer = message.getBytes() ; try { mmOutStream .write(msgBuffer) ; } catch (IOException e) { Log. d ( TAG , "...Error data send: " + e.getMessage() + "..." ) ; } } } }

neilk · Answer

Hi talesdg You can find it here: https://www.element14.com/community/people/neilk/blog/2014/07/18/app-inventor-and-arduino-part-2--send-data-from-arduino-to-android-app Hope this helps. Neil

neilk · Answer

Hi dssen You can find the link to my blog in the previous post. Neil

Sending serial data from Arduino to Android via Bluetooth - NOT ANSWERED Yet

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