Sending data from Android to Arduino using Bluetooth HC-06

Question

I created an Android application to communicate with my Arduino using Bluetooth. But when I send data from my Android device to Arduino, Arduino does not respond to what I sent. I can get a connection from my Android device to my Arduino. So no problem.

Here is my full script for Android.

package nl.handoko.LumaMini; import java.io.IOException; 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.util.Log; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends Activity { private static final String TAG = "LumaMini"; private static final int REQUEST_ENABLE_BT = 1; private BluetoothAdapter btAdapter = null; private BluetoothSocket btSocket = null; private OutputStream outStream = null; Button fourty, thirty, twenty, twelve, automatic, manual; TextView message; // Well known SPP UUID private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); // Server MAC address private static String address = "98:D3:31:30:09:43"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Log.d(TAG, "In onCreate()"); setContentView(R.layout.activity_mainnn); fourty = (Button) findViewById(R.id.button1); thirty = (Button) findViewById(R.id.button4); twenty = (Button) findViewById(R.id.button2); twelve = (Button) findViewById(R.id.button5); automatic = (Button) findViewById(R.id.button3); manual = (Button) findViewById(R.id.button6); message = (TextView) findViewById(R.id.textView1); fourty.setText("40 Leds"); thirty.setText("30 Leds"); twenty.setText("20 Leds"); twelve.setText("12 Leds"); automatic.setText("Automatic"); manual.setText("Manual"); message.setText("Using this app you can take full control of the Luma Mini!" + "When it running on automatic please switch back to manual first before switching to other versions."); btAdapter = BluetoothAdapter.getDefaultAdapter(); checkBTState(); fourty.setOnClickListener(new OnClickListener() { public void onClick(View v) { sendData("a"); Toast msg = Toast.makeText(getBaseContext(), "40 Leds version", Toast.LENGTH_SHORT); msg.show(); } }); thirty.setOnClickListener(new OnClickListener() { public void onClick(View v) { sendData("b"); Toast msg = Toast.makeText(getBaseContext(), "30 Leds version", Toast.LENGTH_SHORT); msg.show(); } }); twenty.setOnClickListener(new OnClickListener() { public void onClick(View v) { sendData("c"); Toast msg = Toast.makeText(getBaseContext(), "20 Leds version", Toast.LENGTH_SHORT); msg.show(); } }); twelve.setOnClickListener(new OnClickListener() { public void onClick(View v) { sendData("d"); Toast msg = Toast.makeText(getBaseContext(), "12 Leds version", Toast.LENGTH_SHORT); msg.show(); } }); automatic.setOnClickListener(new OnClickListener() { public void onClick(View v) { sendData("e"); Toast msg = Toast.makeText(getBaseContext(), "Run automatically", Toast.LENGTH_SHORT); msg.show(); } }); manual.setOnClickListener(new OnClickListener() { public void onClick(View v) { sendData("f"); Toast msg = Toast.makeText(getBaseContext(), "Manually switch Leds", Toast.LENGTH_SHORT); msg.show(); } }); } @Override public void onResume() { super.onResume(); Log.d(TAG, "...In onResume - Attempting client connect..."); // Set up a pointer to the remote node using it 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 = device.createRfcommSocketToServiceRecord(MY_UUID); } 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 to Remote..."); try { btSocket.connect(); Log.d(TAG, "...Connection established and data link opened..."); } catch (IOException e) { try { btSocket.close(); } catch (IOException e2) { errorExit("Fatal Error", "In onResume() and unable to close socket during connection failure" + e2.getMessage() + "."); } } // Create a data stream so we can talk to server. Log.d(TAG, "...Creating Socket..."); try { outStream = btSocket.getOutputStream(); } catch (IOException e) { errorExit("Fatal Error", "In onResume() and output stream creation failed:" + e.getMessage() + "."); } } @Override public void onPause() { super.onPause(); Log.d(TAG, "...In onPause()..."); if (outStream != null) { try { outStream.flush(); } catch (IOException e) { errorExit("Fatal Error", "In onPause() and failed to flush output stream: " + e.getMessage() + "."); } } 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 supported. Aborting."); } else { if (btAdapter.isEnabled()) { Log.d(TAG, "...Bluetooth is enabled..."); } else { //Prompt user to turn on Bluetooth Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT); } } } private void errorExit(String title, String message){ Toast msg = Toast.makeText(getBaseContext(), title + " - " + message, Toast.LENGTH_SHORT); msg.show(); finish(); } private void sendData(String message) { byte[] msgBuffer = message.getBytes(); Log.d(TAG, "...Sending data: " + message + "..."); try { outStream.write(msgBuffer); } catch (IOException e) { String msg = "In onResume() and an exception occurred during write: " + e.getMessage(); msg = msg + ".\n\nCheck that the SPP UUID: " + MY_UUID.toString() + " exists on server.\n\n"; errorExit("Fatal Error", msg); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } } 

And here is my Arduino script:

 #include <SoftwareSerial.h> #include <TimerOne.h> #define Rx 2 #define Tx 3 #define seconds 4 char serialData; // Serial data memory int counter1; // Overflow memory int action; // Action trigger int once = 0; // Run only once SoftwareSerial Bluetooth(Rx, Tx); void setup(){ pinMode(Tx, OUTPUT); // Configure Tx as OUTPUT (Transmitter) pinMode(Rx, INPUT); delay(1000); Bluetooth.begin(9600); Serial.begin(1200); delay(1000); Serial.print("Bluetooth ready"); Bluetooth.flush(); TimerOneSetup(); // Run the setup for Timer One for(int i = 5; i <= 8; i++){ // Make pins 5, 6, 7 and 8 OUTPUT pinMode(i, OUTPUT); } } void interrupt1(){ // Timer One loop counter1++; // Count the amount of seconds has passed if (counter1 == seconds){ // Trigger the next action after a several amount of seconds (Default: 4 seconds) action++; counter1 = 0; } if (action > 3){ // Reset action trigger when after all actions were runned action = 0; } } void loop(){ // Endless loop if (Serial.available()){ // Wait for data recieved from Local device serialData = Serial.read(); // Put recieved data in memory Serial.print("Data recieved from Local device: "); Serial.println(serialData); } if (Bluetooth.available()){ // Wait for data recieved from Bluetooth device serialData = Bluetooth.read(); // Put recieved data in memory Serial.print("Data recieved from Bluetooth device: "); Serial.print(serialData); } if (once == 0){ // This script will be run only once serialData = 'e'; // Put switch on automatic on startup once++; // Get into the next stage which may be run only once } switch(serialData){ // Perform action on state of the switch case 'a': fourtyLeds(); // Show the 40 Leds version of the Luma Mini break; case 'b': thirtyLeds(); // Show the 30 Leds version of the Luma Mini break; case 'c': twentyLeds(); // Show the 20 Leds version of the Luma Mini break; case 'd': twelveLeds(); // Show the 12 Leds version of the Luma Mini break; case 'e': while(serialData == 'e'){ // Keep changing different Led versions of the Luma Mini automatically switch(action){ case 0: // Wait for the action trigger to hit the first action fourtyLeds(); // Show the 40 Leds version of the Luma Mini break; case 1: // Wait for the action trigger to hit the second action twelveLeds(); // Show the 12 Leds version of the Luma Mini break; case 2: // Wait for the action trigger to hit the third action twentyLeds(); // Show the 20 Leds version of the Luma Mini break; case 4: // Wait for the action trigger to hit the fourth action thirtyLeds(); // Show the 30 Leds version of the Luma Mini break;} if (Serial.read() == 'f'){ // Wait for data recieved from Local device serialData = Serial.read(); // Put recieved data in memory Serial.print("Data recieved from Local device: "); Serial.println(serialData); } if (Bluetooth.read() == 'f'){ // Wait for data recieved from Bluetooth device serialData = Bluetooth.read(); // Put recieved data in memory Serial.print("Data recieved from Bluetooth device: "); Serial.println(serialData); } break; } } } void BluetoothSetup(){ pinMode(Tx, OUTPUT); // Configure Tx as OUTPUT (Transmitter) pinMode(Rx, INPUT); // Configure Rx as INPUT (Reciever) Bluetooth.begin(9600); // Set Bluetooth baud rate to default baud rate 38400 Bluetooth.print("\r\n+STWMOD=0\r\n"); // Set the Bluetooth to work in slave mode Bluetooth.print("\r\n+STNA=Luma Mini\r\n"); // Set Bluetooth name to Luma Mini Bluetooth.print("\r\n+STOAUT=1\r\n"); // Permit paired device to connect Bluetooth.print("\r\n+STAUTO=0\r\n"); // Auto-connection should be forbidden here delay(2000); Bluetooth.print("\r\n+INQ=1\r\n"); // Make this Bluetooth Slave inquirable Serial.println("The slave Bluetooth is inquirable!"); delay(2000); Bluetooth.flush(); } void TimerOneSetup(){ Timer1.initialize(1000000); // Initialize Timer One for an overflow exactly every 1 second Timer1.attachInterrupt(interrupt1); // Open the Timer One loop } void fourtyLeds(){ // Show the 40 Leds version of the Luma Mini for(int i = 5; i <= 8; i++){ digitalWrite(i, LOW); } } void thirtyLeds(){ // Show the 30 Leds version of the Luma Mini digitalWrite(5, HIGH); digitalWrite(6, LOW); digitalWrite(7, LOW); digitalWrite(8, LOW); } void twentyLeds(){ // Show the 20 Leds version of the Luma Mini digitalWrite(5, HIGH); digitalWrite(6, HIGH); digitalWrite(7, LOW); digitalWrite(8, HIGH); } void twelveLeds(){ // Show the 12 Leds version of the Luma Mini for (int i = 5; i <= 8; i++){ digitalWrite(i, HIGH); } } 

My question is: how can I send CHAR data from an Android device to Arduino? And what to edit on my script?

Answer 1

I did not view your code. But looking at the question, I propose to keep the Arduino FW encoding until the Android application is tested and developed to a certain level. The way forward could be:

• Disconnect HC-06 from other equipment.
• Make a feedback connection on the HC-06 (i.e., connect the TX and RX outputs of the HC-06 together.
• Then check out the Android app. If the application receives the same as the transmitted one, your Android application works fine, and you can move on with the Arduino FW. Else, the Android app needs to be improved.

You can see a similar question on the bluetooth module HC-05 on Arduino + Debugging .

Answer 2

Here is the code I use and it works great for me.

On the Android side, I only include the bluetooth file, which should be easy to fit into your application. The main advantage is that after your application launches it by calling btConnect (), everything else will be automatic. It finds and connects to your HC-06 without further "human intervention." And if you turn off “HC-06,” Android will continue to watch “HC-06,” to return to online, and reconnect to it.

The sketch of the Arduino sends a signal once per second. If 10 seconds are missed, Android assumes that the connection is lost and will switch to connection mode.

JAVA ANDROID BLUETOOTH FILE:

 package com.exercise.androidanimbuttons; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.content.IntentFilter; import android.widget.Toast; import android.bluetooth.BluetoothSocket; import android.app.ProgressDialog; import android.os.AsyncTask; import java.io.IOException; import java.io.InputStream; import java.util.UUID; import java.util.Set; import android.os.Handler; public class BlueTooth extends vars { private Set<BluetoothDevice> pairedDevices; String address = null; private ProgressDialog progress = null; BluetoothAdapter myBluetooth = null; BluetoothSocket btSocket = null; InputStream mmInStream = null; private Handler myHandler = new Handler(); byte[] buffer = new byte[25]; int readBytes; files filesI = new files(); Handler btH = new Handler(); static final UUID myUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); private SingBroadcastReceiver mReceiver; Runnable btSearch; void stopDiscovery() { if (myBluetooth.isDiscovering()){ myBluetooth.cancelDiscovery(); } } void findCurrentBT() { if (!myBluetooth.isEnabled()){ Intent enableBT = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBT, 0xDEADBEEF); } if (myBluetooth.isDiscovering()){ myBluetooth.cancelDiscovery(); } closeProgress(); progress = ProgressDialog.show(BlueTooth.this, "Searching for headband...", "MAKE SURE THE HEADBAND IS TURNED ON."); progress.setCanceledOnTouchOutside(true); myBluetooth.startDiscovery(); mReceiver = new SingBroadcastReceiver(); IntentFilter ifilter = new IntentFilter(BluetoothDevice.ACTION_FOUND); this.registerReceiver(mReceiver, ifilter); checkSearch(); } private class SingBroadcastReceiver extends BroadcastReceiver { public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (BluetoothDevice.ACTION_FOUND.equals(action)) { BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); String derp = device.getName() + " - " + device.getAddress(); ta(derp); Toast.makeText(context, derp, Toast.LENGTH_LONG); if ((device.getName() != null) && (device.getName().indexOf("HC-06") == 0) && (device.getName().length() == 5)) { myBluetooth.cancelDiscovery(); address = device.getAddress(); new ConnectBT().execute(); } } } } private Runnable readBT = new Runnable() { public void run() { int i; int twoByte = 0; short high = 0, low = 0; try { if (mmInStream.available() > 3) { cnt = 0; readBytes = mmInStream.read(buffer); String S = ""; for (i = 0; i < 2; i++) S += String.format("%03d", buffer[i] & 0xFF)+", "; high = (short)(buffer[3] & 0xFF); low = (short)(buffer[2] & 0xFF); twoByte = ((high << 8) | low); S += String.format("%03d", twoByte) + "\r\n"; filesI.writeALine("nights","data12.txt",S); ta(S); } } catch (IOException e) { ta("err:2 " + e.toString()); } if (btSocket.isConnected()) myHandler.postDelayed(this, 100); } }; public void btConnect() { Disconnect(); findCurrentBT(); } public void btOn() { turnOnLed(); } public void btOff() { turnOffLed(); } public void btDisconnect() { Disconnect(); } private void Disconnect() { if (btSocket!=null) { try { btSocket.close(); } catch (IOException e) { msg("Bluetooth Disconnect Error");} } } private void turnOffLed() { if (btSocket!=null) { try { btSocket.getOutputStream().write("TF".toString().getBytes()); } catch (IOException e) { msg("Error"); } } } private void turnOnLed() { int len; byte[] buffer = new byte[400]; if (btSocket!=null) { try { btSocket.getOutputStream().write("TO".toString().getBytes()); len = btSocket.getInputStream().available(); btSocket.getInputStream().read(buffer,0,len); } catch (IOException e) { msg("Error"); } } } private void msg(String s) { Toast.makeText(getApplicationContext(),s,Toast.LENGTH_LONG).show(); } void closeProgress() { if (progress != null) progress.dismiss(); } private class ConnectBT extends AsyncTask<Void, Void, Void> { @Override protected void onPreExecute() { closeProgress(); progress = ProgressDialog.show(BlueTooth.this, "Connecting to headband...", ""); progress.setCanceledOnTouchOutside(true); } @Override protected Void doInBackground(Void... devices) { try { if (btSocket == null || (!btSocket.isConnected())) { BluetoothDevice dispositivo = myBluetooth.getRemoteDevice(address); btSocket = dispositivo.createInsecureRfcommSocketToServiceRecord(myUUID); BluetoothAdapter.getDefaultAdapter().cancelDiscovery(); btSocket.connect(); } } catch (IOException e) { } return null; } @Override protected void onPostExecute(Void result) { super.onPostExecute(result); if (!btSocket.isConnected()) { msg("Connection Failed. Is the headband turned on?"); } else { msg("Connected."); try { mmInStream = btSocket.getInputStream(); myHandler.postDelayed(readBT, 1000); } catch (IOException e) { ta("err:1 " + e.toString()); } } closeProgress(); } } int cnt = 0; void checkSearch() { if (btSearch != null) return; btSearch = new Runnable(){@Override public void run(){ if ((btSocket != null) && (btSocket.isConnected())) { cnt--; if (cnt < -10) { cnt = 0; btConnect(); } } else if (myBluetooth.isDiscovering()) { cnt++; } btH.postDelayed(this, 1000); fa(cnt); }}; btH.postDelayed(btSearch,1000); } } 

COMPLIANCE WITH ARDUINO ESCHET:

 byte mini [4]; int battery; unsigned long mill = millis(); byte moveCnt = 1; int minuteCnt = 0; int lastMove = 0; int moveA, moveB, moveC, LMoveA, LMoveB, LMoveC, totMove, eyes, LEyes, totEyes; int moveUpA = 0; int moveDnA = 1000; int moveUpB = 0; int moveDnB = 1000; int moveUpC = 0; int moveDnC = 1000; #include <SoftwareSerial.h> SoftwareSerial mySerial(3, 5); // RX, TX void setup() { Serial .begin(9600); mySerial.begin(9600); } void loop() { if (millis() > mill) { mill += 100; minuteCnt++; // *** EYES *** eyes = analogRead(A6); totEyes += abs(eyes-LEyes); LEyes = eyes; // *** MOVEMENT *** --KEEP-- moveA = max(0,analogRead(A1) >> 2); moveA = analogRead(A0); moveB = analogRead(A1); moveC = analogRead(A2); totMove += abs(moveA-LMoveA) + abs(moveB-LMoveB) + abs(moveC-LMoveC); LMoveA = moveA; LMoveB = moveB; LMoveC = moveC; // *** SEND SECOND *** if (minuteCnt >= 10) { minuteCnt = 0; // *** BATTERY *** battery = analogRead(A5); // battery mini[2] = (battery & 0xff); // battery low byte mini[3] = ((battery >> 8) & 0xff); // battery high byte // *** EYES *** mini[0] = min(max(0,totEyes-10),255); totEyes = 0; // *** MOVEMENT *** mini[1] = min(max(0,totMove-30),255); totMove = 0; Serial.print(mini[0]); Serial.print(" "); Serial.print(mini[1]); Serial.print(" "); Serial.print(mini[2]); Serial.print(" "); Serial.println(mini[3]); mySerial.write(mini,4); } } }