Object Tracking Robot





Introduction: Object Tracking Robot

Few weeks ago I thought to make robot that can track object with android phone. At the beginning I searched about it in google. I found some articles but none had source code of android app. My first thought it's "it too hard for me" and I gave up. But I could not stand that I can't make something that I want. So I tried again and after week of hard work with android code I finished my project.

Please if you like my project, vote for me in move it contest. Thanks!

Step 1: Parts

All parts (without smartphone) costed $60:

- arduino LINK TO BUY

- smartphone with android LINK TO BUY

- robot chassis LINK TO BUY

- cables to connect it

- H bridge for DC motors (I use pololu TB6612FNG) LINK TO BUY

- bluetooth module HC-06 LINK TO BUY

- If you want to do PCB go to step 4

Step 2: How Does It Work?

The best way to make it, it's to use android phone with special app which check view from camera recognize position of red color and sends it to arduino over bluetooth. App uses openCV library to image processing. It calculate arithmetic average to check where is red color. Below I added piece of android code to see how it work:

bitmap = Bitmap.createBitmap(mRgba.cols(), mRgba.rows(), Bitmap.Config.ARGB_8888); Utils.matToBitmap(mRgba, bitmap);

int x = 0;

int y = 0;

int all_x = 0;

int all_y = 0;

while(x < 176) {

while(y < 144){

int pixel = bitmap.getPixel(x, y);

int redValue = Color.red(pixel);

int blueValue = Color.blue(pixel);

int greenValue = Color.green(pixel);

if(redValue > 200 && blueValue < 70 && greenValue < 70){


all_x = all_x + x;

all_y = all_y + y;





y = 0;


y = 0;

x = 0;

x_center = all_x / points;

y_center = all_y / points;

Step 3: Connection

Above you can find schema with connection. In next step I added .sch and .brd file from eagle.

I added some jumper wires on the top of the H bridge to do PCB.

Step 4: PCB (optional)

Needed parts to make PCB:

- Everything that was mentioned in first step


- Atmega 8 or 128 or 328

-resistor 1,2 K Ohm

- LED diode (no matter which color)

- linear stabilizer with 5V output

- some female headers

- everything to do PCB read here

- Driller, soldering, etc.

Step 5: Program for Arduino

Arduino code is very basic. It gets data from serial and change it to numbers.

String bluetoothRead, Str_x, Str_y, Str_p;
int x ;
int y ;
int points;
int length;

int pwmMotorA=11;
int pwmMotorB=10;
int ForwardA=8;
int BackA=9;
int ForwardB=6;
int BackB=7;

void setup() {

pinMode(pwmMotorA, OUTPUT);
pinMode(ForwardA, OUTPUT);

pinMode(BackA, OUTPUT);
pinMode(pwmMotorA, OUTPUT);

pinMode(ForwardB, OUTPUT);
pinMode(BackB, OUTPUT);

analogWrite(pwmMotorA, 140);
analogWrite(pwmMotorB, 140);


void loop() {
int i=0;
char commandbuffer[200];



while( Serial.available() && i< 199) {
commandbuffer[i++] = Serial.read();

bluetoothRead = (char*)commandbuffer;
length = bluetoothRead.length();

if(bluetoothRead.substring(0, 1).equals("x")){

int i=1;
while(bluetoothRead.substring(i, i+1) != ("y")){

Str_x = bluetoothRead.substring(1, i);
x = Str_x.toInt();

Str_y = bluetoothRead.substring(i+1, length -1);
y = Str_y.toInt();

Str_p = bluetoothRead.substring(length - 1, length);
points = Str_p.toInt();

i = 1;


if(x < 40){

if(x > 140){

if(x < 140 && x > 40){
if(points == 1){
if(points == 0){
if(points == 2){

void Left(){
digitalWrite(ForwardA, LOW);
digitalWrite(BackA, HIGH);

digitalWrite(ForwardB, HIGH);
digitalWrite(BackB, LOW);


void Right(){

digitalWrite(ForwardA, HIGH);
digitalWrite(BackA, LOW);

digitalWrite(ForwardB, LOW);
digitalWrite(BackB, HIGH);


void Forward(){
digitalWrite(ForwardA, HIGH);
digitalWrite(BackA, LOW);

digitalWrite(ForwardB, HIGH);
digitalWrite(BackB, LOW);

void Back(){
digitalWrite(ForwardA, LOW);
digitalWrite(BackA, HIGH);

digitalWrite(ForwardB, LOW);
digitalWrite(BackB, HIGH);

void Stop(){
digitalWrite(ForwardA, LOW);
digitalWrite(BackA, LOW);

digitalWrite(ForwardB, LOW);
digitalWrite(BackB, LOW);

Step 6: Android App

Instruction how to install app:

1. the first step is download FollowBot.apk file

2.Send apk file to your phone

3.Open file manager and find FollowBot.apk file

4.Click on it and click install (if you have enabled the option to install applications outside the google play you need to turn it on)

5.You have finished the installation, you can run the application

Step 7: Android App (source Code)

Bellow I added source code of my app. This app uses simple bluetooth communication to send data to arduino. OpenCV library is very simply, at the beginning I had some problems with use it but I read about it on internet and easily understood everything. If you have problems with understanding the code, leave comment or send PM.

Step 8: Conclusion

So at the end I can say, that my project works great and that my first thought: "it's too hard for me" was very, very bad.

Any comments welcome. If you have problems, leave a comment and I will try to help you.

Sorry for my English :)


  • Hi Nikus, I also reo...-Yunus ZiyaE

    Yunus ZiyaE made it!


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Hello. I noticed that you do not use external quart to mount. Does it work with internal? How did you load the code on atmega? Thank you.

Sir I did everything as you said but the app isn't working



can you please explain logic of how the car is turning using arduino program i can understand the logic

please please help me

Thanks Nicholas , it's chase red object , need bright red or enough light for camera to recognize and follow ..when I move the red object , my robot make cirlcle move, like trying to find the object . I was using promini and powering all boards with 5v ubec & 2s lipo


Congratulations! It's nice to that somebody made my project. Thanks a lot for picture!

hi Nikus, can i track a shoe so it can follow a human being..
hoping for your reply.


Yes, you can if your shoes are red or orange. You can also always change color to follow in code of app. Thanks for comment!

its a verry cool project....can it be modified to send data over wifi ... i'm tryng to make it work on a nodemcu esp8266 .. and i cant make it work...or if it can send data on local web srver. can u help me... my email is neotrix20@gmail.com

Thanks in advance

hi Mr. nikus i was wondering why you put x < 140 && x > 40 for forward .

I hope I can get a reply from you thank you :)

Hi, to keep some distance from object if there are too many red pixels robot need to go back if there are less it need to go forward.