AndroidRCCar

The previous attempt was in shambles due to the lack of proper products. This time, I got myself a Sainsmart L293D motor driver (actually a cloned version of the ever so popular Adafruit L293D driver) and a handy four wheel drive chassis. Hereupon, the only adjustment  required was the use of analog pins as digital pins. This is the consequence of the motor driver using up all the digital pins and leaving no pins for the Bluetooth shield. I also hooked up the Arduino to a USB power bank.

Tools used:
~ Arduino Uno
~ 4WD Chassis
~ SainSmart motor driver (L293D)
~ Sunkee 30ft Bluetooth Module
~ Anker 15000 mAh power bank


Android:

MainActivity.java 

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
package com.example.androidcar;

import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {
 private boolean mConnected;
 private BluetoothSocket mBluetoothSocket;
 private OutputStream mOutputStream;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  final Button bluetoothConnect = (Button) findViewById(R.id.button1);
  final Button buttonDisconnect = (Button) findViewById(R.id.button2);
  final Button forward = (Button) findViewById(R.id.button3);
  final Button reverse = (Button) findViewById(R.id.button4);
  final Button left = (Button) findViewById(R.id.button5);
  final Button right = (Button) findViewById(R.id.button6);
  bluetoothConnect.setOnClickListener(new View.OnClickListener() {
   public void onClick(View v) {
    try
    {
     //hard coded macAddress
     String macAddress = "20:13:06:26:10:39";
     if (connect(macAddress))
     {
      showToast("Connected");
     }
    }
    catch (final Exception e)
    {
     showToast(e.getMessage());
    }
   }
  });
  buttonDisconnect.setOnClickListener(new View.OnClickListener() {
   public void onClick(View v) {
    disconnect();
    showToast("Disconnected");
   }
  });
  forward.setOnTouchListener(new View.OnTouchListener() {
   @SuppressWarnings("deprecation")
   public boolean onTouch(View v, MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_MOVE)
    {
     forward.setBackgroundColor(Color.GREEN);
     // myButton.setText("Pressed!");
     try
     {
      send("0");
     }
     catch (IOException e)
     {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
     return true;
    }
    if (event.getAction() == MotionEvent.ACTION_UP)
    {
     try
     {
      send("2");
     }
     catch (IOException e)
     {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
     forward.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.btn_default));
     return false;
    }
    return true;
   }
  });
  reverse.setOnTouchListener(new View.OnTouchListener() {
   @SuppressWarnings("deprecation")
   public boolean onTouch(View v, MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_MOVE)
    {
     reverse.setBackgroundColor(Color.RED);
     // myButton.setText("Pressed!");
     try
     {
      send("1");
     }
     catch (IOException e)
     {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
     return true;
    }
    if (event.getAction() == MotionEvent.ACTION_UP)
    {
     reverse.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.btn_default));
     try
     {
      send("2");
     }
     catch (IOException e)
     {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
     return false;
    }
    return true;
   }
  });
  left.setOnTouchListener(new View.OnTouchListener() {
   @SuppressWarnings("deprecation")
   public boolean onTouch(View v, MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_MOVE)
    {
     left.setBackgroundColor(Color.BLUE);
     // myButton.setText("Pressed!");
     try
     {
      send("3");
     }
     catch (IOException e)
     {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
     return true;
    }
    if (event.getAction() == MotionEvent.ACTION_UP)
    {
     try
     {
      send("2");
     }
     catch (IOException e)
     {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
     left.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.btn_default));
     return false;
    }
    return true;
   }
  });
  right.setOnTouchListener(new View.OnTouchListener() {
   @SuppressWarnings("deprecation")
   public boolean onTouch(View v, MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_MOVE)
    {
     right.setBackgroundColor(Color.BLUE);
     // myButton.setText("Pressed!");
     try
     {
      send("4");
     }
     catch (IOException e)
     {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
     return true;
    }
    if (event.getAction() == MotionEvent.ACTION_UP)
    {
     try
     {
      send("2");
     }
     catch (IOException e)
     {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
     right.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.btn_default));
     return false;
    }
    return true;
   }
  });
 }

 @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
 protected void onPause() {
  disconnect();
  super.onPause();
 }

 private void showToast(final String hint) {
  Context context = getApplicationContext();
  if (context != null)
  {
   Toast.makeText(context, hint, Toast.LENGTH_SHORT).show();
  }
 }

 private boolean connect(final String remoteMacAddress) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException, IOException {
  if (mConnected)
  {
   return true;
  }
  // Check that Bluetooth adapter exists.
  BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
  if (bluetoothAdapter == null)
  {
   showToast("Bluetooth adapter not found");
   return false;
  }
  // If Bluetooth adapter exists but it is turned off then turn it on and
  // exit.
  if (!bluetoothAdapter.isEnabled())
  {
   Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
   startActivityForResult(enableBtIntent, 1);
   return false;
  }
  // Connection.
  BluetoothDevice bluetoothDevice = bluetoothAdapter.getRemoteDevice(remoteMacAddress);
  Method m = bluetoothDevice.getClass().getMethod("createRfcommSocket", new Class[] { int.class });
  mBluetoothSocket = (BluetoothSocket) m.invoke(bluetoothDevice, 1);
  mBluetoothSocket.connect();
  // Init output stream. mOutputStream will be used in send() method.
  mOutputStream = mBluetoothSocket.getOutputStream();
  mConnected = true;
  return true;
 }

 private void disconnect() {
  if (mConnected)
  {
   try
   {
    if (mBluetoothSocket != null)
    {
     mBluetoothSocket.close();
     mBluetoothSocket = null;
    }
   }
   catch (IOException e)
   {
    mBluetoothSocket = null;
   }
  }
  mConnected = false;
 }

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

activity_main.xml

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#f1faf3"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button3"
        android:layout_alignParentTop="true"
        android:layout_alignRight="@+id/button3"
        android:text="Connect to Arduino BT"
        android:textColor="#237031"
        android:textStyle="bold" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignRight="@+id/button1"
        android:text="Disconnect"
        android:textColor="#ff0000"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/button2"
        android:layout_alignLeft="@+id/button3"
        android:layout_alignTop="@+id/button2"
        android:layout_toLeftOf="@+id/button4"
        android:textIsSelectable="true" />

    <Button
        android:id="@+id/button5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/button4"
        android:layout_alignLeft="@+id/button3"
        android:layout_below="@+id/button3"
        android:text=" Left "
        android:textSize="30sp"
        android:textStyle="bold" />

    <Button
        android:id="@+id/button6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/button5"
        android:layout_alignRight="@+id/button3"
        android:layout_alignTop="@+id/button5"
        android:text="Right"
        android:textSize="30sp"
        android:textStyle="bold" />

    <Button
        android:id="@+id/button4"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:layout_above="@+id/button2"
        android:layout_centerHorizontal="true"
        android:text="Reverse"
        android:textSize="50sp"
        android:textStyle="bold" />

    <Button
        android:id="@+id/button3"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button4"
        android:layout_below="@+id/button1"
        android:layout_marginTop="15dp"
        android:text="Forward"
        android:textSize="50sp"
        android:textStyle="bold" />

</RelativeLayout>

Arduino 

//Project: Android RC Car
//Author: Ayush Subedi

#include <AFMotor.h> //import Adafruit Motor library
#include <SoftwareSerial.h>// import the serial library
SoftwareSerial newPorts(15, 17); // RX =15= A1, TX=17=A3  
AF_DCMotor motor1(1, MOTOR12_1KHZ); // create motor #1, 1KHz pwm
AF_DCMotor motor2(2, MOTOR12_1KHZ); // create motor #2, 1KHz pwm
AF_DCMotor motor3(3, MOTOR34_1KHZ); // create motor #3, 1KHz pwm
AF_DCMotor motor4(4, MOTOR34_1KHZ); // create motor #4, 1KHz pwm

void setup() {
  newPorts.begin(9600);           
  motor1.setSpeed(255);     // set the speed to 200/255
  motor2.setSpeed(255);     // set the speed to 200/255
  motor3.setSpeed(255);     // set the speed to 200/255
  motor4.setSpeed(255);     // set the speed to 200/255
}

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

void executeReceivedCommand(char command)
{
  switch (command)
  {
    //Forward
  case '0':
    motor1.run(FORWARD);     
    motor2.run(FORWARD);
    motor3.run(FORWARD);
    motor4.run(FORWARD);  
  break;
    
    //Reverse
  case '1':
    motor1.run(BACKWARD);     
    motor2.run(BACKWARD);
    motor3.run(BACKWARD);
    motor4.run(BACKWARD);
   
  break;     

    //Left : skid steering
    case '3':
    motor1.run(FORWARD);
    motor4.run(FORWARD);
    motor2.run(RELEASE);
    motor3.run(RELEASE);
  break;
  
    //Right : skid steering
    case '4':
    motor2.run(FORWARD);
    motor3.run(FORWARD);
    motor1.run(RELEASE);
    motor4.run(RELEASE);
  break;

     //Stall
  case '2':
    motor1.run(RELEASE);      
    motor2.run(RELEASE);
    motor3.run(RELEASE);
    motor4.run(RELEASE);    
  break;
  }
}






























In a nutshell, the Android device sends Char type to Arduino which is used to rotate the motors to maneuver towards a desired direction.

Forward: 0
Reverse: 1
Stop: 2
Left: 3
Right: 4

The car turns left and right by implementing skid steering.


Pictures and Video:









Tags: , , , ,
Ayush Subedi

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi eu sem ultrices, porttitor mi eu, euismod ante. Maecenas vitae velit dignissim velit rutrum gravida sit amet eget risus. Donec sit amet mollis nisi, nec commodo est.