How To Make A Line Follower And A Bluetooth Controlled Robot

Robots are becoming more demanding day by day. In today's automation world everyone is busy designing robots to reduce the cost of production and the damage caused by human errors. Line following and Bluetooth controlled bots are also part of the era of automation. So, in this blog, we are designing a line follower and a Bluetooth controlled robot. And after completing this blog you will understand the basics of motor driver, HC-05 and line sensor.

What is Line follower Robot?

Baisically,  it is a robot designed to follow the line and automatically deliver the object to its destination. This robot uses a closed-loop system to follow the track accurately.

If you check the above image, you will see two to three LED kind of things at the bottom of the robot. These LEDs are nothing but an IR sensor. If you want to know the working of IR sensor, then I request you to check this blog of mine. In that blog, I have explained everything you want to know about IR sensors.

Coming to the point, these IR sensors are mounted on the lower part of the robot which tracks the line and moves towards its destination according to the received input.

What Is HC-05  Bluetooth Controlled Robot?

This type of robot uses the HC-05 Bluettoh Module . This module receives input from the smartphone and functions according to commands received from the user.

I have already written a blog on HC-05 in which I have explained everything about interfacing of HC-05 with Arduino. If you want to know about HC-05 in details, then I request you to check out this HC-05 blog.

It was about the basic introduction of all these subjects, now what do you think are the other components that you might need in the design of a robot? No information !! Don't worry, I tell you.

Circuit Diagram For Line Follower Robot

Till this point what we have discussed up to this point was about the basic introduction of line follower robots and Bluetooth controlled robots, now what do you think are the other components that you might need in the design of a robot? No idea !! Don't worry, I’ll tell you.

Components You May Require to Design A line Follower Robot and a Bluetooth controlled robot

• Chassis
• Wheels and Motors
• Line Sensor
• Motor Driver
• HC-05 Bluetooth Controller

Chassis For The Robot

When building a robot, the first thing you should keep in mind is the chassis. The chassis is like a robot's skeleton that gives strength to the robot.

The chassis is like the backbone of any robot and therefore care must be taken when designing but thanks to Robu, they have already designed the chassis for people like us and this is a product link.

If (LineSensor2 == LOW && LineSensor1 == LOW ) 

{ 

  DigitalWrite(Left_motor1, HIGH) 

  DigitalWrite(Left_motor2, LOW) 

  DigitalWrite(Right_motor1, HIGH) 

  DigitalWrite(Right_motor2, LOW) 

} 

• Second Situation

If the right-sensor is LOW and the second sensor is HIGH, it means that the robot is moving to the left-direction and to return it to its original position we have to use the following line of code.

If (LineSensor1 == LOW  && LineSensor2 == HIGH) 

{ 

  DigitalWrite(Left_motor1, HIGH) 

  DigitalWrite(Left_motor2, LOW) 

  DigitalWrite(Right_motor1, LOW) 

  DigitalWrite(Right_motor2, LOW) 

} 

 If (LineSensor1 == HIGH  && LineSensor2 == LOW) 

{ 

  DigitalWrite(Left_motor1, HIGH) 

  DigitalWrite(Left_motor2, LOW) 

  DigitalWrite(Right_motor1, LOW) 

  DigitalWrite(Right_motor2, LOW) 

} 

If ((LineSensor1 == HIGH  && LineSensor2 == HIGH ) || (LineSensor1 == LOW  && LineSensor2 == LOW)) 

{ 

  DigitalWrite(Left_motor1, LOW) 

  DigitalWrite(Left_motor2, LOW) 

  DigitalWrite(Right_motor1, LOW) 

  DigitalWrite(Right_motor2, LOW) 

} 

In this way we have created a decision-making system for line follower robot, this decision system will help our robot find its way. The full code for the line follower robot is as follows. 

int LineSensor1 =  2;
int LineSensor2 =  3;
int leftMotor1  =  4;
int leftMotor2  =  5;
int rightMotor1 =  6;
int rightMotor2 =  7;

int leftValue =  0;
int rightValue = 0;
void setup()
{
  pinMode (leftMotor, OUTPUT);
  pinMode (rightMotor, OUTPUT);
  pinMode (LineSensor1, INPUT);
  pinMode (LineSensor2, INPUT);
    
}
void loop()
{
  leftValue = digitalRead (leftInput);
  rightValue= digitalRead (rightInput);

if (LineSensor2 == LOW && LineSensor1 == LOW ) 

{ 

  DigitalWrite(Left_motor1, HIGH) 

  DigitalWrite(Left_motor2, LOW) 

  DigitalWrite(Right_motor1, HIGH) 

  DigitalWrite(Right_motor2, LOW) 

}
else if (LineSensor1 == LOW  && LineSensor2 == HIGH) 

{ 

  DigitalWrite(Left_motor1, HIGH) 

  DigitalWrite(Left_motor2, LOW) 

  DigitalWrite(Right_motor1, LOW) 

  DigitalWrite(Right_motor2, LOW) 

}  
 else if (LineSensor1 == HIGH  && LineSensor2 == LOW) 

{ 

  DigitalWrite(Left_motor1, HIGH) 

  DigitalWrite(Left_motor2, LOW) 

  DigitalWrite(Right_motor1, LOW) 

  DigitalWrite(Right_motor2, LOW) 

}
  eles if ((LineSensor1 == HIGH  && LineSensor2 == HIGH ) || (LineSensor1 == LOW  && LineSensor2 == LOW)) 

{ 

  DigitalWrite(Left_motor1, LOW) 

  DigitalWrite(Left_motor2, LOW) 

  DigitalWrite(Right_motor1, LOW) 

  DigitalWrite(Right_motor2, LOW) 

}

Circuit Diagram for Bluetooth controlled Robot

Code For Bluetooth Controlled Robot

Up to this point, we have talked about how to design code for a line follower robot, in this part of this blog we are designing a code used to control a robot using your smartphone goes. To do this, you need to pair the smartphone with HC-05.

Once you successfully connect the Bluetooth module to the smartphone, you will need to install this app in your phone and using the following code you are ready to control your robot manually. 

In this code, we have used the softwareserial.h library to establish communication between the Arduino and HC-05 Bluetooth modules. And using this app we are sending commands to the Arduino. 

#include<SoftwareSerial.h>

#define IN1 4
#define IN2 5
#define IN3 6
#define IN4 7
#define EN1 9
#define EN2 10

SoftwareSerial mySerial(2, 3); // RX, TX

String data;
int btVal;

void setup() 
{  
  //Serial.begin(115200);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);
  pinMode(EN1, OUTPUT);
  pinMode(EN2, OUTPUT);
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, LOW);
  digitalWrite(EN1,HIGH);
  digitalWrite(EN2,HIGH);
  mySerial.begin(9600);
}

void loop()
{
 while (mySerial.available())
 {  
  {  
      data = mySerial.readStringUntil('\n');
      Serial.print(str);             
  } 
    
     btVal= (data.toInt());
    Serial.print("BlueTooth Value ");
    Serial.println(btVal);    



  switch (btVal) 
   {
      case 1:                                
        Serial.println("Forward");
        forward();
        break;

      case 2:                 
        Serial.println("Reverse");
        reverse();
        break;

      case 3:         
        Serial.println("Left");
        left();
        break;
        
      case 4:                     
        Serial.println("Right");
        right();
        break;
        
      case 5:                                            
        Serial.println("Stop");
        stoprobot();
        break;      

  }

 } 
 
                                                              
   if (mySerial.available() < 0)                              
    {
     //Serial.println("No Bluetooth Data ");          
    }
  
}

void forward()
{
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
}

void reverse()
{
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH);
}

void left()
{
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
}

void right()
{
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, LOW);
}

void stoprobot()
{
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, LOW);
}

Conclusion-

In this blog, we have learned how to design a line following and a bluetooth controlled robot, i hope you liked this content. If there are any doubts please let us know in the comment section and we will definitely snswer them.