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Controlling LEDs using an Android device

I have wanted to learn Arduino for a while now. However, I also wanted to incorporate Android in there somewhere. This seemed to be a pretty simple start-up project.

Android App

























Connecting to Arduino Bluetooth shield

On clicking "Connect to Arduino BT", the Android device connects with Arduino. For my purposes, I hard-coded the MAC address of my Arduino Bluetooth in the Android program. 


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bluetoothConnect.setOnClickListener(new View.OnClickListener() {
 public void onClick(View v) {
  try
  {
   String macAddress = "20:13:06:26:10:39";
   if (connect(macAddress))
   {
    greenLED.setVisibility(View.VISIBLE);
    blueLED.setVisibility(View.VISIBLE);
    redLED.setVisibility(View.VISIBLE);
    goRound.setVisibility(View.VISIBLE);
    showToast("Connected");
   }
  }
  catch (final Exception e)
  {
   showToast(e.getMessage());
  }
 }
});

Sending Characters that mean something to the Arduino


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private void send(final String message) throws IOException {
 if (mConnected)
 {
  if (mBluetoothSocket != null)
  {
   mOutputStream.write(message.getBytes());
  }
 }
}

For green LED, if check-box is checked, 1 is sent. If it is unchecked, 0 is sent. Red and green LED follows the same process (with different Char values of course). Finally for the RGB Go Round button, 6 is sent. The code for green LED and RGB Go Round button is below:


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greenLED.setOnCheckedChangeListener(new CheckBox.OnCheckedChangeListener() {
 @Override
 public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
  try
  {
   if (isChecked)
   {
    send("1");      
   }
   else
   {
    send("0");      
   }
  }
  catch (IOException e)
  {
   showToast(e.getMessage());
  }
 }
});

goRound.setOnClickListener(new View.OnClickListener() {
 public void onClick(View v) {
  redLED.setChecked(false);
  greenLED.setChecked(false);
  blueLED.setChecked(false);  
  try
  {
   send("6");
  }
  catch (IOException e)
  {   
   e.printStackTrace();
  }
 }
});

Arduino Side

//Project: Bluetooth LED 

#include <SoftwareSerial.h>// import the serial library
SoftwareSerial newPorts(10, 11); // RX, TX
const byte LED_PINgreen = 13;
const byte LED_PINblue = 9;
const byte LED_PINred=8;
void setup()
{
  newPorts.begin(9600);
  pinMode(LED_PINgreen, OUTPUT);
  pinMode(LED_PINblue, OUTPUT);
  pinMode(LED_PINred, OUTPUT);
  digitalWrite(LED_PINgreen, LOW);
  digitalWrite(LED_PINblue, LOW);
  digitalWrite(LED_PINred, LOW);
}

void loop()
{
  while (newPorts.available() > 0)
  {
    char ch = newPorts.read();
    executeReceivedCommand(ch);
  }
}

void executeReceivedCommand(char command)
{
  switch (command)
  {
    case '0':
      digitalWrite(LED_PINgreen, LOW);
      break;
    case '1':
      digitalWrite(LED_PINgreen, HIGH);
      break;
    case '2':
      digitalWrite(LED_PINblue, LOW);
      break;
    case '3':
      digitalWrite(LED_PINblue, HIGH);
      break;
    case '4':
      digitalWrite(LED_PINred, LOW);
      break;
    case '5':
      digitalWrite(LED_PINred, HIGH);
      break;
     case '6':
      digitalWrite(LED_PINgreen, LOW);
      digitalWrite(LED_PINblue, LOW);
      digitalWrite(LED_PINred, LOW);
      while (newPorts.available() <= 0){
         digitalWrite(LED_PINgreen, HIGH);         
         delay(100);
         digitalWrite(LED_PINgreen, LOW); 
         delay(50);  
         digitalWrite(LED_PINred, HIGH);
         delay(100);
         digitalWrite(LED_PINred, LOW);
         delay(50);
         digitalWrite(LED_PINblue, HIGH);   
         delay(100);
         digitalWrite(LED_PINblue, LOW); 
         delay(50);        
      }     
      break;
  }
}

Demo



Use:

Currently, I have put this assembly behind a lotus vase in my room. Whenever I cannot sleep at night, this will give me some company. In future, I would like to transform it into some sort of "Northern Light" simulator. At this point, I do not have enough experience to know if that is even possible.






Ayush Subedi

Coffee Connoisseur