The Internet of Things (IoT) and the Quantified Self are the two most significant trends in mobile technology. Knowing how to develop software that interfaces with hardware via a mobile device is a skill every mobile developer should possess. Fortunately, many open source hardware solutions exist such as Arduino, Raspberry PI, RedBoard and a few others, which provides developers an opportunity to cultivate a thorough understanding of electronics and learn how to integrate them using software. This discussion will focus on Arduino since it is the most prominent of these solutions.

1. Android Development For Arduino 101
By: Bryan Jones Richardson
Software Engineer
stable|kernel
bryan.richardson@stablekernel.com
stablekernel.com

2. We’re stable|kernel.
stable|kernel is an Atlanta-based mobile development company
to craft smartly-designed mobile applications that connect brands
directly with their users.

3. The Internet of Things?
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4. @stablekernel
The internet of things (IoT) is the
network of physical devices,
embedded with electronics, software,
sensors, actuators, and network
connectivity that enable them to
collect and exchange data.
• Transportation (Street Lights)
• Healthcare
• Agriculture
• Durables & Wearable
• Object Oriented World

5. What Is Arduino?
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6. @stablekernel
Arduino is an open-source electronics
platform based on easy-to-use hardware
and software. It's intended for anyone
making interactive projects.
(Basically, a small computer that you can
connect to anything).
• Uno
• Mega
• Yun
• Minimal Cost Barriers
• Raspberry Pi, Edison, etc.

9. Let’s Make Music
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10. Arduino Communication Strategies
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•USB
•Bluetooth
•Network

11. Android & Arduino via USB
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12. @stablekernel
Android USB Classes
• UsbManager
• UsbDevice
• UsbDeviceConnection
• UsbInterface
• UsbEndpoint
• UsbConstants

13. @stablekernel
Detect Android USB Connection
private final BroadcastReceiver usbConnectionAttachedReceiver = new BroadcastReceiver() {
@Override
public void onReceive(@NonNull Context context, @NonNull Intent intent) {
activeUsbDevice = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
connectUsb();
}
};
private final BroadcastReceiver usbConnectionDetachedReceiver = new BroadcastReceiver() {
@Override
public void onReceive(@NonNull Context context, @NonNull Intent intent) {
UsbDevice detachedDevice = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (detachedDevice == activeUsbDevice) {
disconnectUsb();
}
}
};

14. @stablekernel
Determine if Arduino is Connected
for (int i = 0; i < activeUsbDevice.getInterfaceCount(); i++) {
UsbInterface usbInterface = activeUsbDevice.getInterface(i);
if (usbInterface.getEndpointCount() == 2) {
for (int j = 0; j < endpointCount; j++) {
UsbEndpoint endpoint = usbInterface.getEndpoint(j);
if (endpoint.getType() != UsbConstants.USB_ENDPOINT_XFER_BULK) {
continue;
}
if (endpoint.getDirection() == UsbConstants.USB_DIR_OUT) {
endpointOut = usbInterface.getEndpoint(j);
} else if (endpoint.getDirection() == UsbConstants.USB_DIR_IN) {
endpointIn = usbInterface.getEndpoint(j);
}
}
}
}
}

15. @stablekernel
Establish Communication w/ Arduino
private void setupUSBComm() {
UsbManager manager = (UsbManager) getActivity().getSystemService(Context.USB_SERVICE);
Boolean permitToRead = manager.hasPermission(arduinoDevice);
if (permitToRead) {
connection = manager.openDevice(arduinoDevice);
if (connection != null) {
connection.claimInterface(activeUSBInterface, true);
//requestType, SET_CONTROL_LINE_STATE, value, index, buffer, length, timeout
connection.controlTransfer(RQSID_SET_REQUEST_TYPE, RQSID_SET_CONTROL_LINE_STATE, 0, 0, null, 0, 0);
connection.controlTransfer(RQSID_SET_REQUEST_TYPE, RQSID_SET_LINE_CODING, 0, 0, encodingSetting, 7, 0);
}
} else {
manager.requestPermission(arduinoDevice, permissionIntent);
}
}

16. @stablekernel
Send Android Data to Arduino
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
playNote(position);
}
public void playNote(int note_value) {
byte[] bytesOut = new byte[]{ (byte) note_value};
if(arduinoDevice != null) {
usbArduinoConnection.bulkTransfer(endpointOut, bytesOut, 1, 0);
}
}

17. @stablekernel
Process Android Data on Arduino
int speakerPin = 9;
int tones[] = { 440, 494, 523, 587, 659, 698, 784};
void setup() {
pinMode(speakerPin, OUTPUT);
Serial.begin(9600);
}
void loop() {
if (Serial.available()) {
int incomingByte = Serial.read();
if (incomingByte > -1) {
playNote(incomingByte);
}
}
}
void playNote(int note) {
tone(speakerPin, tones[note], 200);
}

18. @stablekernel
Hardware Setup
Ground Pin 9
Piezo BreadBoardUno USB

19. Android & Arduino via Bluetooth
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20. @stablekernel
Android Bluetooth Classes
<uses-permission android:name = "android.permission.BLUETOOTH_ADMIN"/>
<uses-permission android:name = “android.permission.BLUETOOTH”/>
private BluetoothAdapter bluetoothAdapter;
private BluetoothSocket bluetoothSocket;
private Set<BluetoothDevice> pairedBluetoothDevices;
static final UUID myUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

21. @stablekernel
Connect To BlueTooth Device
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
BluetoothDevice btDevice = bluetoothAdapter.getRemoteDevice(bluetoothAddress);
btSocket = btDevice.createInsecureRfcommSocketToServiceRecord(myUUID);
BluetoothAdapter.getDefaultAdapter().cancelDiscovery();
btSocket.connect();

22. @stablekernel
Send Android Data to Arduino
byte[] bytesOut = new byte[]{ note_value };
try {
btSocket.getOutputStream().write(bytesOut);
} catch (IOException e) {
// handle exception
}

23. @stablekernel
Debugging on Arduino

24. @stablekernel
Debugging on Arduino
digitalWrite(ledPin, LOW);
digitalWrite(ledPin, HIGH);
serialPrint(…);

25. @stablekernel
Hardware Setup
Bluetooth
Transmitter
LED

26. Android & Arduino via Network
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27. @stablekernel
Configure Yun For Connectivity

28. @stablekernel
Configure Yun For Connectivity

29. @stablekernel
Configure Yun For Connectivity

30. @stablekernel
Implement Arduino Code
#include <Bridge.h>
#include <YunServer.h>
#include <YunClient.h>
YunServer server;
...

31. @stablekernel
Implement Arduino Code
void setup() {
...
Bridge.begin();
server.listenOnLocalhost();
server.begin();
}

32. @stablekernel
Implement Arduino Code
void loop() {
YunClient client = server.accept();
if (client) {
process(client);
client.stop();
}
delay(50);
}
void process(YunClient client) {
String incomingNote = client.readStringUntil('/');
playNote(incomingNote.toInt());
}

33. @stablekernel
Send Android Data to Arduino Yun
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
String[] musicalNotes = new String[] { "A","B","C","D","E","F","G"};
ArrayAdapter<String> musicalNotesAdapter = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, musicalNotes);
notesListView.setOnItemClickListener(this);
notesListView.setAdapter(musicalNotesAdapter);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String note = String.valueOf(position);
HttpClient client = new DefaultHttpClient();
String URL = “http://10.0.0.19/arduino/“ + note;
HttpGet request = new HttpGet(URL);
ResponseHandler<String> responseHandler = new BasicResponseHandler();
client.execute(httpget, responseHandler);
}

34. @stablekernel
Hardware Setup

35. Live Demo
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36. Questions?
Business Inquiries:
Sarah Woodward
Director of Business Development
sarah.woodward@stablekernel.com
Bryan Jones Richardson
Software Engineer
bryan.richardson@stablekernel.cm
blog.stablekernel.com