25 March 2013

Bluetooth Android Processing 3

PART THREE


If you happened to land on this page and missed PART ONE, and PART TWO, I would advise you go back and read those sections first.

This is what you'll find in part one:
  • Downloading and setting up the Android SDK
  • Downloading the Processing IDE
  • Setting up and preparing the Android device
  • Running through a couple of Processing/Android sketches on an Andoid phone.
This is what you will find in part two:

  • Introducing Toasts (display messages)
  • Looking out for BluetoothDevices using BroadcastReceivers
  • Getting useful information from a discovered Bluetooth device
  • Connecting to a Bluetooth Device
  • An Arduino Bluetooth Sketch that can be used in this tutorial


InputStream and OutputStream
We will now borrow some code from the Android developers site to help us to establish communication between the Android phone and the Bluetooth shield on the Arduino. By this stage we have already scanned and discovered the bluetooth device and made a successful connection. We now need to create an InputStream and OutputStream to handle the flow of communication between the devices. Let us start with the Android/Processing Side.
The Android Developers site suggests to create a new Thread to handle the incoming and outgoing bytes, because this task uses "blocking" calls. Blocking calls means that the application will appear to be frozen until the call completes. We will create a new Thread to receive bytes through the BluetoothSocket's InputStream, and will send bytes to the Arduino through the BluetoothSocket's OutputStream.
This Thread will continue to listen/send bytes for as long as needed, and will eventually close when we tell it to. We will also need a Handler() to act on any bytes received via the InputStream. The Handler is necessary to transfer information from the IO Thread to the main application thread. This is done by using a Message class. Here is a summary of relevant code that we will subsequently add to the ConnectBluetooth sketch (which was described in Part Two of this tutorial):

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import android.bluetooth.BluetoothSocket;
import java.io.InputStream;
import java.io.OutputStream;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

// Message types used by the Handler
public static final int MESSAGE_WRITE = 1;
public static final int MESSAGE_READ = 2;

// The Handler that gets information back from the Socket
private final Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MESSAGE_WRITE:
//Do something when writing
break;
case MESSAGE_READ:
//Get the bytes from the msg.obj
byte[] readBuf = (byte[]) msg.obj;
// construct a string from the valid bytes in the buffer
String readMessage = new String(readBuf, 0, msg.arg1);
break;
}
}
};



private class SendReceiveBytes implements Runnable {
private BluetoothSocket btSocket;
private InputStream btInputStream = null;
private OutputStream btOutputStream = null;
String TAG = "SendReceiveBytes";

public SendReceiveBytes(BluetoothSocket socket) {
btSocket = socket;
try {
btInputStream = btSocket.getInputStream();
btOutputStream = btSocket.getOutputStream();
}
catch (IOException streamError) {
Log.e(TAG, "Error when getting input or output Stream");
}
}

public void run() {
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()

// Keep listening to the InputStream until an exception occurs
while (true) {
try {
// Read from the InputStream
bytes = btInputStream.read(buffer);
// Send the obtained bytes to the UI activity
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
}
catch (IOException e) {
Log.e(TAG, "Error reading from btInputStream");
break;
}
}
}

/* Call this from the main activity to send data to the remote device */
public void write(byte[] bytes) {
try {
btOutputStream.write(bytes);
}
catch (IOException e) {
Log.e(TAG, "Error when writing to btOutputStream");
}
}

/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
btSocket.close();
}
catch (IOException e) {
Log.e(TAG, "Error when closing the btSocket");
}
}
}

Notice that we place an endless loop in the run() method to continuously read bytes from the InputStream. This continuous process of reading bytes needs to be a different thread from the main application otherwise it would cause the program to "hang". This thread passes any read bytes to the main application by using the Handler's .sendToTarget() method.
You will also notice the use of Log.e(TAG, ".....") commands. This is useful for debugging Android problems, especially when you comae across errors that generate a "caused the application to close unexpectedly" dialog box to appear on your phone.  I personally created a shortcut of the adb.exe on my desktop and changed the target to
  • "c:\[INSERT FOLDER]\Android\android-sdk\platform-tools\adb.exe" logcat *:E
The adb.exe program comes with the Android-SDK downloaded in Part One . Once you find the adb.exe on your hard-drive, you just create a shortcut on your desktop. Right-click the shortcut, choose "Properties" and as indicated above, you change the last bit of the Target to
  • logcat *:E
So if you get an unexpected error on your android device, just go back to your laptop, and double-click on your new desktop adb.exe shortcut to get a better idea of where your program has gone wrong.

We will now incorporate the sketch above into our ConnectBluetooth Android/Processing App, however we will call this updated version "SendReceiveBytes"
Once we have created a successful connection, and created our Input/OutputStreams, we will send a single letter "r" to the Arduino via bluetooth, and if all goes well, we should see the light on the RGB Chainable LED turn Red (see further down for Arduino sketch).
I borrowed Byron's code snippet from this site: to convert a string ("r") to a byte array, which is used in the write() method. The relevant code can be found on lines 199-208 below. I have bolded the lines numbers to make it a little easier to see the changes I made (compared to the previous sketch).

Android/Processing Sketch 6: SendReceiveBytes
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/* SendReceiveBytes: Written by ScottC on 25 March 2013 using 
Processing version 2.0b8
Tested on a Samsung Galaxy SII, with Android version 2.3.4
Android ADK - API 10 SDK platform */

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.widget.Toast;
import android.view.Gravity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;

import java.util.UUID;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
public BluetoothSocket scSocket;


boolean foundDevice=false; //When true, the screen turns green.
boolean BTisConnected=false; //When true, the screen turns purple.
String serverName = "ArduinoBasicsServer";

// Message types used by the Handler
public static final int MESSAGE_WRITE = 1;
public static final int MESSAGE_READ = 2;
String readMessage="";

//Get the default Bluetooth adapter
BluetoothAdapter bluetooth = BluetoothAdapter.getDefaultAdapter();

/*The startActivityForResult() within setup() launches an
Activity which is used to request the user to turn Bluetooth on.
The following onActivityResult() method is called when this
Activity exits. */
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode==0) {
if (resultCode == RESULT_OK) {
ToastMaster("Bluetooth has been switched ON");
}
else {
ToastMaster("You need to turn Bluetooth ON !!!");
}
}
}


/* Create a BroadcastReceiver that will later be used to
receive the names of Bluetooth devices in range. */
BroadcastReceiver myDiscoverer = new myOwnBroadcastReceiver();


/* Create a BroadcastReceiver that will later be used to
identify if the Bluetooth device is connected */
BroadcastReceiver checkIsConnected = new myOwnBroadcastReceiver();


// The Handler that gets information back from the Socket
private final Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MESSAGE_WRITE:
//Do something when writing
break;
case MESSAGE_READ:
//Get the bytes from the msg.obj
byte[] readBuf = (byte[]) msg.obj;
// construct a string from the valid bytes in the buffer
readMessage = new String(readBuf, 0, msg.arg1);
break;
}
}
};


void setup() {
orientation(LANDSCAPE);
/*IF Bluetooth is NOT enabled, then ask user permission to enable it */
if (!bluetooth.isEnabled()) {
Intent requestBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(requestBluetooth, 0);
}


/*If Bluetooth is now enabled, then register a broadcastReceiver to report any
discovered Bluetooth devices, and then start discovering */
if (bluetooth.isEnabled()) {
registerReceiver(myDiscoverer, new IntentFilter(BluetoothDevice.ACTION_FOUND));
registerReceiver(checkIsConnected, new IntentFilter(BluetoothDevice.ACTION_ACL_CONNECTED));

//Start bluetooth discovery if it is not doing so already
if (!bluetooth.isDiscovering()) {
bluetooth.startDiscovery();
}
}
}


void draw() {
//Display a green screen if a device has been found,
//Display a purple screen when a connection is made to the device
if (foundDevice) {
if (BTisConnected) {
background(170, 50, 255); // purple screen
}
else {
background(10, 255, 10); // green screen
}
}

//Display anything received from Arduino
text(readMessage, 10, 10);
}


/* This BroadcastReceiver will display discovered Bluetooth devices */
public class myOwnBroadcastReceiver extends BroadcastReceiver {
ConnectToBluetooth connectBT;

@Override
public void onReceive(Context context, Intent intent) {
String action=intent.getAction();
ToastMaster("ACTION:" + action);

//Notification that BluetoothDevice is FOUND
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
//Display the name of the discovered device
String discoveredDeviceName = intent.getStringExtra(BluetoothDevice.EXTRA_NAME);
ToastMaster("Discovered: " + discoveredDeviceName);

//Display more information about the discovered device
BluetoothDevice discoveredDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
ToastMaster("getAddress() = " + discoveredDevice.getAddress());
ToastMaster("getName() = " + discoveredDevice.getName());

int bondyState=discoveredDevice.getBondState();
ToastMaster("getBondState() = " + bondyState);

String mybondState;
switch(bondyState) {
case 10:
mybondState="BOND_NONE";
break;
case 11:
mybondState="BOND_BONDING";
break;
case 12:
mybondState="BOND_BONDED";
break;
default:
mybondState="INVALID BOND STATE";
break;
}
ToastMaster("getBondState() = " + mybondState);

//Change foundDevice to true which will make the screen turn green
foundDevice=true;

//Connect to the discovered bluetooth device (SeeedBTSlave)
if (discoveredDeviceName.equals("SeeedBTSlave")) {
ToastMaster("Connecting you Now !!");
unregisterReceiver(myDiscoverer);
connectBT = new ConnectToBluetooth(discoveredDevice);
//Connect to the the device in a new thread
new Thread(connectBT).start();
}
}

//Notification if bluetooth device is connected
if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
ToastMaster("CONNECTED _ YAY");

while (scSocket==null) {
//do nothing
}
ToastMaster("scSocket" + scSocket);
BTisConnected=true; //turn screen purple
if (scSocket!=null) {
SendReceiveBytes sendReceiveBT = new SendReceiveBytes(scSocket);
new Thread(sendReceiveBT).start();
String red = "r";
byte[] myByte = stringToBytesUTFCustom(red);
sendReceiveBT.write(myByte);
}
}
}
}
public static byte[] stringToBytesUTFCustom(String str) {
char[] buffer = str.toCharArray();
byte[] b = new byte[buffer.length << 1];
for (int i = 0; i < buffer.length; i++) {
int bpos = i << 1;
b[bpos] = (byte) ((buffer[i]&0xFF00)>>8);
b[bpos + 1] = (byte) (buffer[i]&0x00FF);
}
return b;
}

public class ConnectToBluetooth implements Runnable {
private BluetoothDevice btShield;
private BluetoothSocket mySocket = null;
private UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

public ConnectToBluetooth(BluetoothDevice bluetoothShield) {
btShield = bluetoothShield;
try {
mySocket = btShield.createRfcommSocketToServiceRecord(uuid);
}
catch(IOException createSocketException) {
//Problem with creating a socket
Log.e("ConnectToBluetooth", "Error with Socket");
}
}

@Override
public void run() {
/* Cancel discovery on Bluetooth Adapter to prevent slow connection */
bluetooth.cancelDiscovery();

try {
/*Connect to the bluetoothShield through the Socket. This will block
until it succeeds or throws an IOException */
mySocket.connect();
scSocket=mySocket;
}
catch (IOException connectException) {
Log.e("ConnectToBluetooth", "Error with Socket Connection");
try {
mySocket.close(); //try to close the socket
}
catch(IOException closeException) {
}
return;
}
}

/* Will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mySocket.close();
}
catch (IOException e) {
}
}
}


private class SendReceiveBytes implements Runnable {
private BluetoothSocket btSocket;
private InputStream btInputStream = null;
private OutputStream btOutputStream = null;
String TAG = "SendReceiveBytes";

public SendReceiveBytes(BluetoothSocket socket) {
btSocket = socket;
try {
btInputStream = btSocket.getInputStream();
btOutputStream = btSocket.getOutputStream();
}
catch (IOException streamError) {
Log.e(TAG, "Error when getting input or output Stream");
}
}


public void run() {
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()

// Keep listening to the InputStream until an exception occurs
while (true) {
try {
// Read from the InputStream
bytes = btInputStream.read(buffer);
// Send the obtained bytes to the UI activity
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
}
catch (IOException e) {
Log.e(TAG, "Error reading from btInputStream");
break;
}
}
}


/* Call this from the main activity to send data to the remote device */
public void write(byte[] bytes) {
try {
btOutputStream.write(bytes);
}
catch (IOException e) {
Log.e(TAG, "Error when writing to btOutputStream");
}
}


/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
btSocket.close();
}
catch (IOException e) {
Log.e(TAG, "Error when closing the btSocket");
}
}
}



/* My ToastMaster function to display a messageBox on the screen */
void ToastMaster(String textToDisplay) {
Toast myMessage = Toast.makeText(getApplicationContext(),
textToDisplay,
Toast.LENGTH_SHORT);
myMessage.setGravity(Gravity.CENTER, 0, 0);
myMessage.show();
}


Arduino Sketch: Testing the Input/OutputStream
We will borrow the Arduino Sketch from my previous blog post (here). Which should change the RGB LED to red when it receives an "r" through the bluetooth serial port.
You should also be able to send text to the Android phone by opening up the Serial Monitor on the Arduino IDE (although found this to be somewhat unreliable/unpredictable. I may need to investigate a better way of doing this, but it should work to some capacity (I sometimes find that a couple of letters go missing on transmision).
In this sketch I am using a Bluetooth shield like this one,  and have connected a Grove Chainable RGB LED to it using a Grove Universal 4 Pin Cable.

Bluetooth Shield with Grove RGB LED

Arduino Sketch 2: Bluetooth RGB Colour Changer

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/* This project combines the code from a few different sources.
This project was put together by ScottC on the 15/01/2013
http://arduinobasics.blogspot.com/

Bluetooth slave code by Steve Chang - downloaded from :
http://www.seeedstudio.com/wiki/index.php?title=Bluetooth_Shield

Grove Chainable RGB code can be found here :
http://www.seeedstudio.com/wiki/Grove_-_Chainable_RGB_LED#Introduction

*/

#include <SoftwareSerial.h> //Software Serial Port

#define uint8 unsigned char
#define uint16 unsigned int
#define uint32 unsigned long int

#define RxD 6 // This is the pin that the Bluetooth (BT_TX) will transmit to the Arduino (RxD)
#define TxD 7 // This is the pin that the Bluetooth (BT_RX) will receive from the Arduino (TxD)

#define DEBUG_ENABLED 1

int Clkpin = 9; //RGB LED Clock Pin (Digital 9)
int Datapin = 8; //RGB LED Data Pin (Digital 8)

SoftwareSerial blueToothSerial(RxD,TxD);
/*----------------------SETUP----------------------------*/ void setup() {
Serial.begin(9600); // Allow Serial communication via USB cable to computer (if required)
pinMode(RxD, INPUT); // Setup the Arduino to receive INPUT from the bluetooth shield on Digital Pin 6
pinMode(TxD, OUTPUT); // Setup the Arduino to send data (OUTPUT) to the bluetooth shield on Digital Pin 7
pinMode(13,OUTPUT); // Use onboard LED if required.
setupBlueToothConnection(); //Used to initialise the Bluetooth shield

pinMode(Datapin, OUTPUT); // Setup the RGB LED Data Pin
pinMode(Clkpin, OUTPUT); // Setup the RGB LED Clock pin

}
/*----------------------LOOP----------------------------*/ void loop() {
digitalWrite(13,LOW); //Turn off the onboard Arduino LED
char recvChar;
while(1){
if(blueToothSerial.available()){//check if there's any data sent from the remote bluetooth shield
recvChar = blueToothSerial.read();
Serial.print(recvChar); // Print the character received to the Serial Monitor (if required)

//If the character received = 'r' , then change the RGB led to display a RED colour
if(recvChar=='r'){
Send32Zero(); // begin
DataDealWithAndSend(255, 0, 0); // first node data
Send32Zero(); // send to update data
}

//If the character received = 'g' , then change the RGB led to display a GREEN colour
if(recvChar=='g'){
Send32Zero(); // begin
DataDealWithAndSend(0, 255, 0); // first node data
Send32Zero(); // send to update data
}

//If the character received = 'b' , then change the RGB led to display a BLUE colour
if(recvChar=='b'){
Send32Zero(); // begin
DataDealWithAndSend(0, 0, 255); // first node data
Send32Zero(); // send to update data
}
}

//You can use the following code to deal with any information coming from the Computer (serial monitor)
if(Serial.available()){
recvChar = Serial.read();

//This will send value obtained (recvChar) to the phone. The value will be displayed on the phone.
blueToothSerial.print(recvChar);
}
}
}

//The following code is necessary to setup the bluetooth shield ------copy and paste----------------
void setupBlueToothConnection()
{
blueToothSerial.begin(38400); //Set BluetoothBee BaudRate to default baud rate 38400
blueToothSerial.print("\r\n+STWMOD=0\r\n"); //set the bluetooth work in slave mode
blueToothSerial.print("\r\n+STNA=SeeedBTSlave\r\n"); //set the bluetooth name as "SeeedBTSlave"
blueToothSerial.print("\r\n+STOAUT=1\r\n"); // Permit Paired device to connect me
blueToothSerial.print("\r\n+STAUTO=0\r\n"); // Auto-connection should be forbidden here
delay(2000); // This delay is required.
blueToothSerial.print("\r\n+INQ=1\r\n"); //make the slave bluetooth inquirable
Serial.println("The slave bluetooth is inquirable!");
delay(2000); // This delay is required.
blueToothSerial.flush();
}

//The following code snippets are used update the colour of the RGB LED-----copy and paste------------
void ClkProduce(void){
digitalWrite(Clkpin, LOW);
delayMicroseconds(20);
digitalWrite(Clkpin, HIGH);
delayMicroseconds(20);
}
void Send32Zero(void){
unsigned char i;
for (i=0; i<32; i++){
digitalWrite(Datapin, LOW);
ClkProduce();
}
}

uint8 TakeAntiCode(uint8 dat){
uint8 tmp = 0;
if ((dat & 0x80) == 0){
tmp |= 0x02;
}

if ((dat & 0x40) == 0){
tmp |= 0x01;
}

return tmp;
}
// gray data
void DatSend(uint32 dx){
uint8 i;
for (i=0; i<32; i++){
if ((dx & 0x80000000) != 0){
digitalWrite(Datapin, HIGH);
} else {
digitalWrite(Datapin, LOW);
}

dx <<= 1;
ClkProduce();
}
}
// data processing
void DataDealWithAndSend(uint8 r, uint8 g, uint8 b){
uint32 dx = 0;

dx |= (uint32)0x03 << 30; // highest two bits 1,flag bits
dx |= (uint32)TakeAntiCode(b) << 28;
dx |= (uint32)TakeAntiCode(g) << 26;
dx |= (uint32)TakeAntiCode(r) << 24;

dx |= (uint32)b << 16;
dx |= (uint32)g << 8;
dx |= r;

DatSend(dx);
}



Some GUI Buttons

My aim is to somewhat recreate the experience from a similar project I blogged about (here). However I wanted to have much more control over the GUI. I will start by creating a few buttons, but will later look at making a much more fun/interactive design (hopefully). The following simple Android/Processing sketch will be totally independant of the sketch above, it will be a simple App that will have a few buttons which will change the colour of the background on the phone. Once we get the hang of this, we will incorporate it into our Bluetooth Sketch.
To start off with, we will need to download an Android/Processing library which will allow us to create the buttons that we will use in our App.
Unzip the apwidgets_r44.zip file and put the apwidgets folder into your default Processing sketch "libraries" folder. For more information about installing contributed libraries into you Processing IDE - have a look at this site.
You will need to reboot your Processing IDE before being able to see the "apwidgets" item appear in the Processing IDE's menu,
  • Sketch > Import Library :  Under the "Contributed" list item.
If you cannot see this menu item, then you will need to try again. Make sure you are putting it into the default sketch libraries folder, which may not be in the same folder as the processing IDE. To find out the default sketch location - look here:
  • File > Preferences > Sketchbook location
Ok, now that you have the APWidgets library installed in your Processing IDE, make sure you are still in Andorid Mode, and copy the following sketch into the IDE, and run the program on your device. This sketch borrows heavily from the APWidgets Button example, which can be found here.

Android/Processing Sketch 7: Button Presser
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import apwidgets.*;

APWidgetContainer widgetContainer;
APButton redButton, greenButton, blueButton, offButton;
String buttonText="";
int buttonWidth=0;
int buttonHeight=0;
int n=4; //number of buttons
int gap=10; //gap between buttons


void setup() {
buttonWidth=((width/n)-(n*gap));
buttonHeight=(height/2);
widgetContainer = new APWidgetContainer(this); //create new container for widgets
redButton =new APButton((buttonWidth*(n-4)+(gap*1)), gap, buttonWidth, buttonHeight, "RED"); //Create a RED button
greenButton = new APButton((buttonWidth*(n-3)+(gap*2)), gap, buttonWidth, buttonHeight, "GREEN"); //Create a GREEN button
blueButton = new APButton((buttonWidth*(n-2)+(gap*3)), gap, buttonWidth, buttonHeight, "BLUE"); //Create a BLUE button
offButton = new APButton((buttonWidth*(n-1)+(gap*4)), gap, buttonWidth, buttonHeight, "OFF"); //Create a OFF button
widgetContainer.addWidget(redButton); //place red button in container
widgetContainer.addWidget(greenButton); //place green button in container
widgetContainer.addWidget(blueButton);//place blue button in container
widgetContainer.addWidget(offButton);//place off button in container
background(0); //Start with a black background
}



void draw() {
//Change the text based on the button being pressed.
text(buttonText, 10, buttonHeight+(buttonHeight/2));
}



//onClickWidget is called when a widget is clicked/touched
void onClickWidget(APWidget widget) {

if (widget == redButton) { //if the red button was clicked
buttonText="RED";
background(255, 0, 0);
}
else if (widget == greenButton) { //if the green button was clicked
buttonText="GREEN";
background(0, 255, 0);
}
else if (widget == blueButton) { //if the blue button was clicked
buttonText="BLUE";
background(0, 0, 255);
}
else if (widget == offButton) { //if the off button was clicked
buttonText="OFF";
background(0);
}
}

The sketch creates 4 buttons, one for Red, Green, Blue and Off. In this example, we use the onClickWidget() method to deal with button_click events, which we use to change the colour of the background.  I forgot to include the following line in the setup() method:
  • orientation(LANDSCAPE);
This will force the application to go into landscape mode, which is what I intended.


Bluetooth Buttons : Adding Buttons to the Bluetooth project

We will now incorporate the Buttons sketch into our Bluetooth project so that when we press a button, it will send a letter to the Arduino via Bluetooth. The letter will be used by the Arduino to decide what colour to display on the Chainable RGB LED. We will still keep the previous functionality of changing the LED to RED when a successful Input/OutputStream is created, because this will be the signal to suggest that it is now ok to press the buttons (and we should see it work).

Here is the updated Android/Processing sketch

Android/Processing Sketch 8: Bluetooth App1

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/* BluetoothApp1: Written by ScottC on 25 March 2013 using 
Processing version 2.0b8
Tested on a Samsung Galaxy SII, with Android version 2.3.4
Android ADK - API 10 SDK platform
Apwidgets version: r44 */

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.widget.Toast;
import android.view.Gravity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;

import java.util.UUID;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import apwidgets.*;
public BluetoothSocket scSocket;


//Used for the GUI**************************************
APWidgetContainer widgetContainer;
APButton redButton, greenButton, blueButton, offButton;
String buttonText="";
int buttonWidth=0;
int buttonHeight=0;
int n=4; //number of buttons
int gap=10; //gap between buttons

boolean foundDevice=false; //When true, the screen turns green.
boolean BTisConnected=false; //When true, the screen turns purple.
String serverName = "ArduinoBasicsServer";

// Message types used by the Handler
public static final int MESSAGE_WRITE = 1;
public static final int MESSAGE_READ = 2;
String readMessage="";

//Used to send bytes to the Arduino
SendReceiveBytes sendReceiveBT=null;

//Get the default Bluetooth adapter
BluetoothAdapter bluetooth = BluetoothAdapter.getDefaultAdapter();

/*The startActivityForResult() within setup() launches an
Activity which is used to request the user to turn Bluetooth on.
The following onActivityResult() method is called when this
Activity exits. */
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode==0) {
if (resultCode == RESULT_OK) {
ToastMaster("Bluetooth has been switched ON");
}
else {
ToastMaster("You need to turn Bluetooth ON !!!");
}
}
}


/* Create a BroadcastReceiver that will later be used to
receive the names of Bluetooth devices in range. */
BroadcastReceiver myDiscoverer = new myOwnBroadcastReceiver();


/* Create a BroadcastReceiver that will later be used to
identify if the Bluetooth device is connected */
BroadcastReceiver checkIsConnected = new myOwnBroadcastReceiver();



// The Handler that gets information back from the Socket
private final Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MESSAGE_WRITE:
//Do something when writing
break;
case MESSAGE_READ:
//Get the bytes from the msg.obj
byte[] readBuf = (byte[]) msg.obj;
// construct a string from the valid bytes in the buffer
readMessage = new String(readBuf, 0, msg.arg1);
break;
}
}
};



void setup() {
orientation(LANDSCAPE);

//Setup GUI********************************
buttonWidth=((width/n)-(n*gap));
buttonHeight=(height/2);
widgetContainer = new APWidgetContainer(this); //create new container for widgets
redButton =new APButton((buttonWidth*(n-4)+(gap*1)), gap, buttonWidth, buttonHeight, "RED"); //Create a RED button
greenButton = new APButton((buttonWidth*(n-3)+(gap*2)), gap, buttonWidth, buttonHeight, "GREEN"); //Create a GREEN button
blueButton = new APButton((buttonWidth*(n-2)+(gap*3)), gap, buttonWidth, buttonHeight, "BLUE"); //Create a BLUE button
offButton = new APButton((buttonWidth*(n-1)+(gap*4)), gap, buttonWidth, buttonHeight, "OFF"); //Create a OFF button
widgetContainer.addWidget(redButton); //place red button in container
widgetContainer.addWidget(greenButton); //place green button in container
widgetContainer.addWidget(blueButton);//place blue button in container
widgetContainer.addWidget(offButton);//place off button in container
background(0); //Start with a black background

/*IF Bluetooth is NOT enabled, then ask user permission to enable it */
if (!bluetooth.isEnabled()) {
Intent requestBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(requestBluetooth, 0);
}

/*If Bluetooth is now enabled, then register a broadcastReceiver to report any
discovered Bluetooth devices, and then start discovering */
if (bluetooth.isEnabled()) {
registerReceiver(myDiscoverer, new IntentFilter(BluetoothDevice.ACTION_FOUND));
registerReceiver(checkIsConnected, new IntentFilter(BluetoothDevice.ACTION_ACL_CONNECTED));

//Start bluetooth discovery if it is not doing so already
if (!bluetooth.isDiscovering()) {
bluetooth.startDiscovery();
}
}
}


void draw() {
//Display a green screen if a device has been found,
//Display a purple screen when a connection is made to the device
if (foundDevice) {
if (BTisConnected) {
background(170, 50, 255); // purple screen
}
else {
background(10, 255, 10); // green screen
}
}


//Change the text based on the button being pressed.
text(buttonText, 10, buttonHeight+(buttonHeight/2));

//Display anything received from Arduino
text(readMessage, 10, buttonHeight+(buttonHeight/2)+30);
}



/* This BroadcastReceiver will display discovered Bluetooth devices */
public class myOwnBroadcastReceiver extends BroadcastReceiver {
ConnectToBluetooth connectBT;

@Override
public void onReceive(Context context, Intent intent) {
String action=intent.getAction();
ToastMaster("ACTION:" + action);

//Notification that BluetoothDevice is FOUND
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
//Display the name of the discovered device
String discoveredDeviceName = intent.getStringExtra(BluetoothDevice.EXTRA_NAME);
ToastMaster("Discovered: " + discoveredDeviceName);

//Display more information about the discovered device
BluetoothDevice discoveredDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
ToastMaster("getAddress() = " + discoveredDevice.getAddress());
ToastMaster("getName() = " + discoveredDevice.getName());

int bondyState=discoveredDevice.getBondState();
ToastMaster("getBondState() = " + bondyState);

String mybondState;
switch(bondyState) {
case 10:
mybondState="BOND_NONE";
break;
case 11:
mybondState="BOND_BONDING";
break;
case 12:
mybondState="BOND_BONDED";
break;
default:
mybondState="INVALID BOND STATE";
break;
}
ToastMaster("getBondState() = " + mybondState);

//Change foundDevice to true which will make the screen turn green
foundDevice=true;

//Connect to the discovered bluetooth device (SeeedBTSlave)
if (discoveredDeviceName.equals("SeeedBTSlave")) {
ToastMaster("Connecting you Now !!");
unregisterReceiver(myDiscoverer);
connectBT = new ConnectToBluetooth(discoveredDevice);
//Connect to the the device in a new thread
new Thread(connectBT).start();
}
}

//Notification if bluetooth device is connected
if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
ToastMaster("CONNECTED _ YAY");
int counter=0;
while (scSocket==null) {
//do nothing
}
ToastMaster("scSocket" + scSocket);
BTisConnected=true; //turn screen purple
if (scSocket!=null) {
sendReceiveBT = new SendReceiveBytes(scSocket);
new Thread(sendReceiveBT).start();
String red = "r";
byte[] myByte = stringToBytesUTFCustom(red);
sendReceiveBT.write(myByte);
}
}
}
}

public static byte[] stringToBytesUTFCustom(String str) {
char[] buffer = str.toCharArray();
byte[] b = new byte[buffer.length << 1];
for (int i = 0; i < buffer.length; i++) {
int bpos = i << 1;
b[bpos] = (byte) ((buffer[i]&0xFF00)>>8);
b[bpos + 1] = (byte) (buffer[i]&0x00FF);
}
return b;
}

public class ConnectToBluetooth implements Runnable {
private BluetoothDevice btShield;
private BluetoothSocket mySocket = null;
private UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

public ConnectToBluetooth(BluetoothDevice bluetoothShield) {
btShield = bluetoothShield;
try {
mySocket = btShield.createRfcommSocketToServiceRecord(uuid);
}
catch(IOException createSocketException) {
//Problem with creating a socket
Log.e("ConnectToBluetooth", "Error with Socket");
}
}

@Override
public void run() {
/* Cancel discovery on Bluetooth Adapter to prevent slow connection */
bluetooth.cancelDiscovery();

try {
/*Connect to the bluetoothShield through the Socket. This will block
until it succeeds or throws an IOException */
mySocket.connect();
scSocket=mySocket;
}
catch (IOException connectException) {
Log.e("ConnectToBluetooth", "Error with Socket Connection");
try {
mySocket.close(); //try to close the socket
}
catch(IOException closeException) {
}
return;
}
}

// Will allow you to get the socket from this class
public BluetoothSocket getSocket() {
return mySocket;
}

/* Will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mySocket.close();
}
catch (IOException e) {
}
}
}



private class SendReceiveBytes implements Runnable {
private BluetoothSocket btSocket;
private InputStream btInputStream = null;
;
private OutputStream btOutputStream = null;
String TAG = "SendReceiveBytes";

public SendReceiveBytes(BluetoothSocket socket) {
btSocket = socket;
try {
btInputStream = btSocket.getInputStream();
btOutputStream = btSocket.getOutputStream();
}
catch (IOException streamError) {
Log.e(TAG, "Error when getting input or output Stream");
}
}

public void run() {
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()

// Keep listening to the InputStream until an exception occurs
while (true) {
try {
// Read from the InputStream
bytes = btInputStream.read(buffer);
// Send the obtained bytes to the UI activity
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
}
catch (IOException e) {
Log.e(TAG, "Error reading from btInputStream");
break;
}
}
}

/* Call this from the main activity to send data to the remote device */
public void write(byte[] bytes) {
try {
btOutputStream.write(bytes);
}
catch (IOException e) {
Log.e(TAG, "Error when writing to btOutputStream");
}
}

/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
btSocket.close();
}
catch (IOException e) {
Log.e(TAG, "Error when closing the btSocket");
}
}
}



/* My ToastMaster function to display a messageBox on the screen */
void ToastMaster(String textToDisplay) {
Toast myMessage = Toast.makeText(getApplicationContext(),
textToDisplay,
Toast.LENGTH_SHORT);
myMessage.setGravity(Gravity.CENTER, 0, 0);
myMessage.show();
}




//onClickWidget is called when a widget is clicked/touched
void onClickWidget(APWidget widget) {
String sendLetter = "";

//Disable the previous Background colour changers
foundDevice=false;
BTisConnected=false;

if (widget == redButton) { //if the red button was clicked
buttonText="RED";
background(255, 0, 0);
sendLetter = "r";
}
else if (widget == greenButton) { //if the green button was clicked
buttonText="GREEN";
background(0, 255, 0);
sendLetter = "g";
}
else if (widget == blueButton) { //if the blue button was clicked
buttonText="BLUE";
background(0, 0, 255);
sendLetter = "b";
}
else if (widget == offButton) { //if the off button was clicked
buttonText="OFF";
background(0);
sendLetter = "x";
}

byte[] myByte = stringToBytesUTFCustom(sendLetter);
sendReceiveBT.write(myByte);
}

The sketch above has been thrown together without much planning or consideration for code efficiency. It was deliberately done this way so that you could see and follow the incremental approach used to create this Android/Processing Bluetooth App. I will do my best to rewrite and simplify some of the code, however, I don't anticipate the final sketch will be a short script.
You should have noticed that I included a fourth button called an "off" button. This will turn off the RGB led. However, the Arduino code in its current format does not know what to do with an 'x'. So we will update the sketch as follows:

Arduino Sketch 3: Bluetooth RGB Colour Changer (with OFF option)

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/* This project combines the code from a few different sources.
This project was put together by ScottC on the 15/01/2013
http://arduinobasics.blogspot.com/

Bluetooth slave code by Steve Chang - downloaded from :
http://www.seeedstudio.com/wiki/index.php?title=Bluetooth_Shield

Grove Chainable RGB code can be found here :
http://www.seeedstudio.com/wiki/Grove_-_Chainable_RGB_LED#Introduction

Updated on 25 March 2013: Receive 'x' to turn off RGB LED.

*/

#include <SoftwareSerial.h> //Software Serial Port

#define uint8 unsigned char
#define uint16 unsigned int
#define uint32 unsigned long int

#define RxD 6 // This is the pin that the Bluetooth (BT_TX) will transmit to the Arduino (RxD)
#define TxD 7 // This is the pin that the Bluetooth (BT_RX) will receive from the Arduino (TxD)

#define DEBUG_ENABLED 1

int Clkpin = 9; //RGB LED Clock Pin (Digital 9)
int Datapin = 8; //RGB LED Data Pin (Digital 8)

SoftwareSerial blueToothSerial(RxD, TxD);


/*----------------------SETUP----------------------------*/
void setup() {
Serial.begin(9600); // Allow Serial communication via USB cable to computer (if required)
pinMode(RxD, INPUT); // Setup the Arduino to receive INPUT from the bluetooth shield on Digital Pin 6
pinMode(TxD, OUTPUT); // Setup the Arduino to send data (OUTPUT) to the bluetooth shield on Digital Pin 7
pinMode(13, OUTPUT); // Use onboard LED if required.
setupBlueToothConnection(); //Used to initialise the Bluetooth shield

pinMode(Datapin, OUTPUT); // Setup the RGB LED Data Pin
pinMode(Clkpin, OUTPUT); // Setup the RGB LED Clock pin
}


/*----------------------LOOP----------------------------*/
void loop() {
digitalWrite(13, LOW); //Turn off the onboard Arduino LED
char recvChar;
while (1) {
if (blueToothSerial.available()) {//check if there's any data sent from the remote bluetooth shield
recvChar = blueToothSerial.read();
Serial.print(recvChar); // Print the character received to the Serial Monitor (if required)

//If the character received = 'r' , then change the RGB led to display a RED colour
if (recvChar=='r') {
Send32Zero(); // begin
DataDealWithAndSend(255, 0, 0); // first node data
Send32Zero(); // send to update data
}

//If the character received = 'g' , then change the RGB led to display a GREEN colour
if (recvChar=='g') {
Send32Zero(); // begin
DataDealWithAndSend(0, 255, 0); // first node data
Send32Zero(); // send to update data
}

//If the character received = 'b' , then change the RGB led to display a BLUE colour
if (recvChar=='b') {
Send32Zero(); // begin
DataDealWithAndSend(0, 0, 255); // first node data
Send32Zero(); // send to update data
}

//If the character received = 'x' , then turn RGB led OFF
if (recvChar=='x') {
Send32Zero(); // begin
DataDealWithAndSend(0, 0, 0); // first node data
Send32Zero(); // send to update data
}
}

//You can use the following code to deal with any information coming from the Computer (serial monitor)
if (Serial.available()) {
recvChar = Serial.read();

//This will send value obtained (recvChar) to the phone. The value will be displayed on the phone.
blueToothSerial.print(recvChar);
}
}
}



//The following code is necessary to setup the bluetooth shield ------copy and paste----------------
void setupBlueToothConnection()
{
blueToothSerial.begin(38400); //Set BluetoothBee BaudRate to default baud rate 38400
blueToothSerial.print("\r\n+STWMOD=0\r\n"); //set the bluetooth work in slave mode
blueToothSerial.print("\r\n+STNA=SeeedBTSlave\r\n"); //set the bluetooth name as "SeeedBTSlave"
blueToothSerial.print("\r\n+STOAUT=1\r\n"); // Permit Paired device to connect me
blueToothSerial.print("\r\n+STAUTO=0\r\n"); // Auto-connection should be forbidden here
delay(2000); // This delay is required.
blueToothSerial.print("\r\n+INQ=1\r\n"); //make the slave bluetooth inquirable
Serial.println("The slave bluetooth is inquirable!");
delay(2000); // This delay is required.
blueToothSerial.flush();
}


//The following code snippets are used update the colour of the RGB LED-----copy and paste------------
void ClkProduce(void) {
digitalWrite(Clkpin, LOW);
delayMicroseconds(20);
digitalWrite(Clkpin, HIGH);
delayMicroseconds(20);
}
void Send32Zero(void) {
unsigned char i;
for (i=0; i<32; i++) {
digitalWrite(Datapin, LOW);
ClkProduce();
}
}



uint8 TakeAntiCode(uint8 dat) {
uint8 tmp = 0;
if ((dat & 0x80) == 0) {
tmp |= 0x02;
}

if ((dat & 0x40) == 0) {
tmp |= 0x01;
}
return tmp;
}


// gray data
void DatSend(uint32 dx) {
uint8 i;
for (i=0; i<32; i++) {
if ((dx & 0x80000000) != 0) {
digitalWrite(Datapin, HIGH);
}
else {
digitalWrite(Datapin, LOW);
}
dx <<= 1;
ClkProduce();
}
}

// data processing
void DataDealWithAndSend(uint8 r, uint8 g, uint8 b) {
uint32 dx = 0;

dx |= (uint32)0x03 << 30; // highest two bits 1,flag bits
dx |= (uint32)TakeAntiCode(b) << 28;
dx |= (uint32)TakeAntiCode(g) << 26;
dx |= (uint32)TakeAntiCode(r) << 24;

dx |= (uint32)b << 16;
dx |= (uint32)g << 8;
dx |= r;

DatSend(dx);
}



Well that concludes part 3.
Part 4 is a summary of the finished project with videos, screenshots, parts used etc.
I hope you found this tutorial useful. I would love to receive any advice on how I could improve these tutorials (please put your recommendations in comments below).

Reason for this Project:
While there are quite a few people creating Android/Arduino projects, I have not been able to find many that show how these are being accomplished using the Android/Processing IDE, and even less on how they are using Bluetooth in their Android/Processing projects. I hope my piecing of information will spark some creative Bluetooth projects of your own.



PART 4: Navigate here.





48 comments:

  1. Hi Scott,

    Thanks so much for sharing your work with us! I am in a team that is trying to develop an Android app that can interface through Bluetooth with an Arduino-driven sensor and we've been dutifully following your tutorial to build our app.

    We were able to get our phone screen to turn purple in the previous steps but are having trouble with this section. When we test the "SendReceiveBytes" sketch on my friend's Motorola Atrix 2, it turns the screen black momentarily and then displays a "sketch failed unexpectedly" message. Per your instructions, we've looked into the log file and find the following to be relevant to the launch of our app.... any ideas on what could be going on here?

    Log file:
    --------- beginning of /dev/log/main
    --------- beginning of /dev/log/system
    04-25 20:57:58.854 3746 3746 E Trace : error opening trace file: Permission denied (13)
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: FATAL EXCEPTION: Animation Thread
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: java.lang.SecurityException: Need BLUETOOTH permission: Neither user 10127 nor current process has android.permission.BLUETOOTH.
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: at android.os.Parcel.readException(Parcel.java:1425)
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: at android.os.Parcel.readException(Parcel.java:1379)
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: at android.bluetooth.IBluetooth$Stub$Proxy isEnabled(IBluetooth.java:1710)
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: at android.bluetooth.BluetoothAdapter.isEnabled(BluetoothAdapter.java:453)
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: at processing.test.sketch_130425a.sketch_130425a.setup(sketch_130425a.java:125)
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: at processing.core.PApplet.handleDraw(Unknown Source)
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: at processing.core.PGraphicsAndroid2D.requestDraw(PGraphicsAndroid2D.java:169)
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: at processing.core.PApplet.run(Unknown Source)
    04-25 20:57:59.295 3746 3762 E AndroidRuntime: at java.lang.Thread.run(Thread.java:856)
    04-25 20:57:59.545 3770 3770 E Trace : error opening trace file: Permissiondenied (13)
    04-25 20:57:59.635 3785 3785 E Trace : error opening trace file: Permissiondenied (13)
    04-25 20:57:59.845 3804 3804 E Trace : error opening trace file: Permissiondenied (13)
    04-25 20:58:00.036 2569 3830 E MediatorService: Cannot create command object
    04-25 20:58:00.076 3833 3833 E Trace : error opening trace file: Permission denied (13)
    04-25 20:58:00.656 3853 3853 E Trace : error opening trace file: Permission denied (13)
    04-25 20:58:02.038 1368 3889 E Adreno200-ES20: : GL_INVALID_ENUM
    04-25 20:58:02.338 3900 3900 E Trace : error opening trace file: Permission denied (13)
    04-25 20:58:02.728 3922 3922 E Trace : error opening trace file: Permission denied (13)
    04-25 20:58:09.666 2569 2569 E LSApp_App: Sending Message to Handler (com.motorola.contextual.virtualsensor.locationsensor.LocationDetection$MessageHandler) {41d6e950}: msg :1010002
    04-25 20:59:07.317 4055 4055 E Trace : error opening trace file: Permission denied (13)

    Thank you in advance for any help!!

    ReplyDelete
    Replies
    1. Hi David,
      Please double-check that you have enabled the Bluetooth permissions as per part one of this tutorial series. Each Processing/Android sketch needs to include these permissions as you move further into the tutorial.
      Let me know how you go.
      Regards Scott.

      Delete
  2. Hello Scott,

    firstly congratulate you on the good job you have done. just great!

    I agree with you on the reason for your project. I am trying to create a gui into processing to control my house and comunicate with blootooht, i have just started and i found your blog!.

    I have a different blootooth module (BlueSMiRF Gold) hooked to arduino and i am struggling with this device to get the connection.

    Any idea about the config for it? is it needed?

    Get a connection from a pc is quite straightforward but from android i am having troubles.

    Thank you for your help!

    ReplyDelete
    Replies
    1. Hi Oscar,

      From what I can see, you will definitely need to adapt my code in order to use your Bluetooth module. The "void setupBlueToothConnection()" method in the Arduino code is specific for the Bluetooth shield that I am using. My suggestion to you is to set up an Arduino sketch which will successfully connect to your computer via Bluetooth, and use the same Arduino sketch with the Android program.
      You may want to investigate which device (Arduino or PC) you have set as the master and which is the slave. I'm pretty sure I treated the Bluetooth module on the Arduino as the slave in my example.
      You need to make sure that your Bluetooth Smirf module is discoverable after you upload your Arduino sketch.
      I hope that helps???
      Scott

      Delete
    2. Thank Scott for your reply!

      After some changes into the configuration i managed to make it work. I had to change indise the method connect2Bt()the line:

      btSocket = btShield.createRfcommSocketToServiceRecord(uuid);

      for:

      btShield.createRfcommSocketToServiceRecord(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));

      being the same that makes it works.

      After this change and pairing with the Smirf i got the comunication.

      What i don´t understand is why take so long for getting up the communication. 5 to 10 seconds.

      Also sometimes i get the message:

      "That's weird. Proc 157 got signal 3, but there's no stack trace."

      I coudn´t find any information about this issue. Do you know what it could be about?

      Thanks for your help!

      Delete
    3. Hi Oscar.
      Am glad you managed to get it to work. I know I had some problems with the UUID when I was first trying to put this all together. I tried changing the UUID, but it came up with some errors. I am not exactly sure whether each Bluetooth manufacturer uses this UUID on their modules and I am not sure how one would go about changing it if they needed to. And no, I have not come across the error you describe.
      Regards
      Scott

      Delete
    4. I also started getting this signal 3 error you described. Did you ever trace the source of the error?
      Regards,
      AJ

      Delete
    5. Hi Allan,
      I have never seen that error on my system but I anticipate that it has something to do with the creation of a Socket. See if resetting the Bluetooth module on the Arduino and Bluetooth on the Android device makes any difference. This may be one for the forums.

      Delete
    6. Thanks Scott,
      That does remedy the issue, but is a bit extreme.
      This is a great site by the way. Thanks for taking the time and effort in putting this together. We all appreciate it.
      Regards,
      AJ

      Delete
    7. Hi Allan,

      It may have something to do with the fact that I don't have any code related to closing the socket (safely). But not 100% sure.

      And thanks for the feedback :)

      Scott

      Delete
  3. First of all, great work! I followed your tutorial up to the example with detecting button inputs. I see an error popping up in the console as soon as I press a button:

    java.lang.reflect.InvocationTargetException
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at apwidgets.APWidget.onClick(APWidget.java:69)
    at android.view.View.performClick(View.java:4084)
    at android.view.View$PerformClick.run(View.java:16966)
    at android.os.Handler.handleCallback(Handler.java:615)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:4931)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:558)
    at dalvik.system.NativeStart.main(Native Method)
    Caused by: java.lang.NullPointerException
    at processing.test.bluetooth_connect1.bluetooth_connect1$Connect2BtDevice.write(bluetooth_connect1.java:297)
    at processing.test.bluetooth_connect1.bluetooth_connect1.onClickWidget(bluetooth_connect1.java:159)
    ... 14 more

    ReplyDelete
    Replies
    1. Hi Fresco,

      Have you tried the ApWidgets sketch from their site here ?

      And just wanted to confirm whether you are having problems with Sketch 7 or 8? And if problem with Android processing sketch 8, did sketch 7 work for you ?

      Delete
  4. Hi Scott,

    Thanks for your fast response :)

    I've used this library: https://code.google.com/p/apwidgets/downloads/detail?name=apwidgets_r44_for_Java1.5.zip&can=2&q=

    apwidgets_r44_for_java1.5

    and i had troubles starting with sketch 7!

    Thanks for any further hints!
    Best

    ReplyDelete
    Replies
    1. In your error log, it mentions "Connect2BtDevice.write()"
      I don't have any mention of this in sketch 7. Have you modified sketch 7 ?

      Scott

      Delete
  5. Hi Scott,

    One last question. In the above reference implementation for Android specifically in the message handler. You have a section of the code as follows:

    case MESSAGE_WRITE:
    //Do something when writing

    Do you have some representative code that would operate in the context of the handler?

    Thanks Scott

    ReplyDelete
    Replies
    1. Hi Allan,

      That is a very good question.
      mHandler is triggered in the example via this line:
      mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer).sendToTarget();

      And is used to notify the UI Thread only when new data is discovered.
      We don't want to hold up the UI Thread while polling for new data, so we use a different Thread to do this.

      The example above does not use the mHandler section "when" Writing, and almost seems redundant. However, think of mHandler as a unidirectional alert mechanism.
      When reading, we alert the UI that we have discovered new bytes.
      You would use "case MESSAGE_WRITE" when you want to alert the main UI about something related to writing. You could even create your own codes for other alerts if you wanted to.

      To give you an example of how you could use this section:
      On line 339 of sketch 8 we have this code:

      public void write(byte[] bytes) {
      try { btOutputStream.write(bytes);
      } catch (IOException e) {
      Log.e(TAG, "Error when writing to btOutputStream");
      }}

      In the example above, I have chosen to use Log.e as a way of reporting an exception with the writing process. However, I could have replaced that line with something like:

      mHandler.obtainMessage(MESSAGE_WRITE, bytes).sendToTarget();

      Therefore if there is an exception with the writing of bytes, the main UI will be notified, and then you can use the case MESSAGE_WRITE section of mHandler to do what you want, like display a message or STOP writing or something else.

      Some more information on the handler can be found here

      Hope that answers your question.

      Regards
      Scott


      Delete
  6. Hello Scott.

    First of all, thumbs up for the amazing work. You should be teaching these materials in a college or something :) Thank you so much for taking the time to post this.
    Second, I was hoping you could help me identify the problem. I have used the Arduino Sketch 3, along with the Android/Processing Sketch 8. The app would pair with the Arduino Bluetooth and retrieve all the info from it. However, there's no possible communication. When I click a button on the app, nothing happens on the board.
    Please note that I am using Arduino Uno board, XBee Shield V1.1, and Bluetooth Bee Model HC-06 V2.0.

    Best Regards,

    Huda :)

    ReplyDelete
    Replies
    1. Hi Huda,
      I am assuming that you have successfully completed all of the other steps without any issues.
      Are you using a chainable RGB led?
      If not then I am assuming that you would have to modify the Arduino sketch. It is sometimes hard to know where things go wrong when I am not sure about your specific setup. But maybe answer my first couple of questions and then perhaps I can point you in the right direction.

      Delete
    2. Thanks for your reply :)

      Yes all the other steps were trouble-free.

      I am not using any RGB Led yet. I am just using the on-board Led, pin no. 13. I modified the Arduino sketch accordingly. If you may give me your email address, I would send you the setup of the whole thing. I really need help with this because it is the first time for me I work with Arduino via Bluetooth. Please help.

      Best Regards,

      Huda.

      Delete
    3. Hi Huda,
      Perhaps send me a message through YouTube?

      Regards
      Scott

      Delete
    4. I tagged you with the pictures via Google+, You can message me through Youtube. I've already sent you a message.

      Much regards Scott,

      Huda..

      Delete
  7. Hi Scott,

    thanks for the valuable code.
    I went into a problem in sketches 6 and 8 with a compiler error:
    "test.sendreceivebytes.SendReceiveBytes is already defined in processing.test.sendreceivebytes"

    -compile:
    [javac] Since compiler setting isn't classic or modern, ignoring fork setting.
    [javac] Since compiler setting isn't classic or modern, ignoring fork setting.
    [javac] Since compiler setting isn't classic or modern, ignoring fork setting.
    [javac] Compiling 3 source files to C:\DOKUME~1\ADMINI~1\LOKALE~1\Temp\android5333549756587688394sketch\bin\classes
    [javac] Since compiler setting isn't classic or modern, ignoring fork setting.
    [javac] C:\DOKUME~1\ADMINI~1\LOKALE~1\Temp\android5333549756587688394sketch\src\processing\test\sendreceivebytes\SendReceiveBytes.java:294: processing.test.sendreceivebytes.SendReceiveBytes is already defined in processing.test.sendreceivebytes
    [javac] private class SendReceiveBytes implements Runnable {
    [javac] ^
    [javac] 1 error

    BUILD FAILED
    C:\Dokumente und Einstellungen\Administrator\Lokale Einstellungen\Anwendungsdaten\Android\android-sdk\tools\ant\build.xml:712: The following error occurred while executing this line:
    C:\Dokumente und Einstellungen\Administrator\Lokale Einstellungen\Anwendungsdaten\Android\android-sdk\tools\ant\build.xml:726: Compile failed; see the compiler error output for details.

    Thanks för a hint!

    Kind Regards
    Uwe

    ReplyDelete
    Replies
    1. Hi Uwe,

      Try replacing all references to SendReceiveBytes in the sketch to something unique like SRBytes. Someone else also had this problem, and am not too sure why, but they seemed to solve the problem by changing the conflicting name of the class SendReceiveBytes to something else.

      Let me know if this works for you.
      Scott

      Delete
    2. Hi Scott,

      thanks for your fast reply. I have done following "changes":

      189: SRBytes sendReceiveBT = new SRBytes(scSocket);
      ...

      258: private class SRBytes implements Runnable {
      ...

      264: public SRBytes(BluetoothSocket socket) {
      ...

      and it works;-).
      OS is WinXP, Android project. Maybe this helps anyone in finding the reason for the behaviour.

      Kind Regards
      Uwe

      Delete
  8. Hi Scott,
    Im trying to connect to a bluetooth device using your code on my phone but its not able to connect/pair to it.
    I replaced the string "SeeedBTSlave" with my device's name but it keeps hanging.

    ReplyDelete
    Replies
    1. Im able to get upto the green light part but then it gets stuck. I've tried changing my device's name to "SeeedBTSlave" but it still hangs.

      Delete
  9. Hello Scott C , Thanks for everything . i learnt so many things through you .
    i have a small problem , i got the sketch 6 my phone (galaxys4) . i try to connect to HC-05 bluetooth module . when i download the code , it can found a device ("discovered=hc-05) and says Found . but It cant connect to the device . there fore i cant send data what s wrong you think ? thanks in advance .

    ReplyDelete
  10. My guess is that you will have to modify the Arduino code to accommodate your specific Bluetooth device. There are many different Bluetooth devices out there... So this is where I would start. You may want to look for Arduino examples on the internet that use your specific device.

    ReplyDelete
  11. thanks scott it works now .i just changed the name of the bt device .(blueToothSerial.print("\r\n+STNA=SeeedBTSlave\r\n")) i put HC-05 instead of SeeedBTslave ...
    how can i send letter(r ,g ,b ) to arduino ? becoz when i download the android sketch. i just have seen purple screen . i cant do anything else ( like a open keyboard or sth else )

    ReplyDelete
    Replies
    1. Work your way through to sketch 8.
      On sketch 8 you will see on line 384, 389 and 394 that it will send the letters r g and b respectively.

      If you are getting the purple screen - you should have an active connection. And the letters should transmit.

      Delete
  12. Hello Scott C , first of all ,Thank you so much for these parts again and again. these concern my final year project . and you helped me so much .i modified processing sketch 8 . i controlled a bulb and curtain via bluetooth . so far i just send data to arduino through bluetooth . but i want to do it vice verso which means that , for instance i want to display temperature on my android application . so i need to send data from arduino to application using LM35 or sth like it . . can you help about it pls . i donno what to change or add .

    ReplyDelete
    Replies
    1. Hi Burakozen - you didn't say whether you were having problems on the Arduino side or the Android application side.

      On the Arduino side:
      You can send values to the Android application using:
      blueToothSerial.print(x);
      where x is the value that you want to send.

      On the Application side:
      Sketch 8 should already be displaying received data on the screen.
      The variable that you need to search for in the Android sketch is:
      readMessage

      Look through the android sketch for that variable and then trace it back as required - to find out how it displays the value.

      Delete
  13. Hello ,Thanks for replying Scott C , its important for me becoz its last step for my project . i tried what u say . also with some alternatives .
    On arduino side i putted these into setup() and loop() //not same sketch , i defined int x = 100 ; and i also defined another variable as char x (i inspired of revChar ) //
    blueToothSerial.print("burak :");


    blueToothSerial.println(x,DEC);

    *****on processing side "***
    firstly i tried without change , later i modified in order to see well like this
    textSize(50);
    fill(0);
    text(readMessage,300,50);

    // but didnt worked . :( .should i change/ add something more on processing or arduino side ? ..
    Thank you Scott again

    ReplyDelete
    Replies
    1. Hi Burakozen,
      Unfortunately, blogs are not really set up for this type of troubleshooting.
      This kind of question is best served in a forum - where you can easily and logically post your code. It is too hard to identify what is going wrong without looking at what you have done to the code.
      The only advice I can give you is to check to make sure that you have this part of the code included on the processing side:
      private final Handler mHandler = new Handler() {
      ....}
      Also make sure that you have not gone beyond the dimensions of the screen when you define
      text(....300,50)
      Other than that - best to post your query into a forum.
      Regards
      Scott

      Delete
  14. Yes , you're right Scott ,I'm sorry . i posted your code to stackoverflow . if you have time , pls check it out . http://stackoverflow.com/questions/23540754/send-data-from-arduino-to-android-app-via-bluetooth

    Thank you so much .

    ReplyDelete
    Replies
    1. Hi Burak,
      I have posted a comment on the code you used. Not sure if it will help or not.
      I do recommend that you update the comments in your code to match the changes that you have made. Otherwise it becomes very difficult to understand and follow.

      Delete
    2. Burak -
      I forgot to ask "What are you using to trigger the Arduino to send the data via Bluetooth?"
      In my example above - you can use the Serial monitor to send data from your computer to your android device via the Arduino (providing the computer and Arduino are connected via USB cable). This functionality is already provided within the code. No modification required.

      However, if you are trying to send data to the android device without using the Serial monitor, then you will need to change the Arduino code accordingly. However, the Processing code should be able to receive and display it.

      Delete
  15. I just would like to inform you guys that codes in this blog works using the Android Mode of Processing version 2.0b7. But encounters a compilation problem using Android Mode of Processing Version 2.2.1. The 2.2.1 version detects an error around a "void run()" syntax while the 2.0b7 version detects no errors and successfully compiles the code. I just don't know if it is a bug in the 2.2.1 version.

    ReplyDelete
    Replies
    1. Thanks Myrdal,
      This is really good to know.

      Delete
    2. Guys, I think I found the problem regarding the reason why processing 2.2.1 could not compile the codes. This is due to an " @override " before a " public void run() { " , version 2.0b7 compiles the code with or without the override, but only compiles on version 2.2.1 without it.

      Delete
  16. Is it possible for the APButton to be invisible or transparent? Wherein the user is able to click on it but not see it?

    ReplyDelete
    Replies
    1. I guess it depends on the button's foreground and background colour. I am sure you could make them the same to make it "invisible"

      Delete
  17. Is it possible for an APButton to be a clickable image instead?

    ReplyDelete
    Replies
    1. Hi Myrdal.

      I cannot see why you couldn't have a clickable image instead.

      Delete
    2. I was able to create a clickable image. Instead of using APButtons, I used Processing image instead in creating the button.

      Delete
    3. Awesome - that is good to know

      Delete
  18. Hello Scott
    Thank you for your great work.
    I have a little problem when receiving bytes from BT device:
    In my application, the arduino card send every second a lttle text of ten characters and very often the first character is not received!
    What do you think about that?
    Thank you very much!

    ReplyDelete
    Replies
    1. Hi Anonymous,
      Not sure.. but maybe you should send a leading character (as a consistent junk character) that you could ignore at the other end... for example a character that you know will not be used routinely like "~" or "^" or some other character of your choice.
      Send this character a few times before your actual text, and it should fix it. I have no idea why it would not receive the first character though..

      SEND: ~~~~^ArduinoBasics

      on receiving end - look for the "~" character, and then do a while loop to wait for the "^" character. Once it finds the "^" character, then deal with the remaining text.

      Not sure if that helps you??

      Delete

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