Line Following Robot

Parts for Consideration

In summary, the L298N motor controller is a versatile and robust solution for driving and controlling DC motors and stepper motors in various electronic projects and applications. Its dual H-bridge design, high current/voltage capabilities, and compatibility with different control systems make it a popular choice among hobbyists and engineers for motor control projects.

It's essential to provide appropriate external power supplies to the Vs and Vss pins, and the logic control signals (ENA, IN1, IN2, ENB, IN3, IN4) are typically controlled by a microcontroller or other digital control circuits. Careful attention to the logic levels and power requirements is crucial for proper operation of the L298N motor controller.

Various Notes

Adjustment (if available): Some IR Proximity Sensors come with a sensitivity adjustment potentiometer. If present, this pin allows you to adjust the sensor's sensitivity to better suit the environmental conditions or the type of surface being detected.

Emitter (LED): In sensors with a separate emitter and receiver, this pin is connected to the infrared LED (Light Emitting Diode) that emits the infrared light used for detection.

Receiver (Photodiode): In sensors with a separate emitter and receiver, this pin is connected to the photodiode that receives the reflected infrared light. The intensity of the received light is used to determine the surface characteristics.

It's crucial to refer to the datasheet or documentation provided by the specific manufacturer for accurate pinout information, as variations can exist. Additionally, when integrating the sensor into a circuit, ensure proper voltage levels, and take note of any polarity considerations.

Building the Project

2. Write the Arduino Sketch

// Made by MakerLessons

int ENA = 11; //ENA connected to digital pin 11

int ENB = 3; //ENB connected to digital pin 3

int MOTOR_A1 = 10; // MOTOR_A1 connected to digital pin 10

int MOTOR_A2 = 9; // MOTOR_A2 connected to digital pin 9

int MOTOR_B1 = 6; // MOTOR_B1 connected to digital pin 6

int MOTOR_B2 = 5; // MOTOR_B2 connected to digital pin 5

int RIGHT = A0; // RIGHT IR sensor connected to analog pin A0

int LEFT = A1; // LEFT IR sensor connected to analog pin A1

// the setup function runs once when you press reset or power the board

void setup() {

pinMode(ENA, OUTPUT); // initialize ENA pin as an output

pinMode(ENB, OUTPUT); // initialize ENB pin as an output

pinMode(MOTOR_A1, OUTPUT); // initialize MOTOR_A1 pin as an output

pinMode(MOTOR_A2, OUTPUT); // initialize MOTOR_A2 pin as an output

pinMode(MOTOR_B1, OUTPUT); // initialize MOTOR_B1 pin as an output

pinMode(MOTOR_B2, OUTPUT); // initialize MOTOR_B2 pin as an output

pinMode(RIGHT, INPUT); // initialize RIGHT IR pin as an input

pinMode(LEFT, INPUT); // initialize LEFT IR pin as an input

}

// the loop function runs over and over again forever

void loop() {

if (analogRead(RIGHT)<=35 && analogRead(LEFT)<=35) //compare the both sensor to decide the direction

{

  //MOVE FORWARD//

  analogWrite(ENA, 100); // set right motors speed

  analogWrite(ENB, 100); // set left motors speed

  //run right motors clockwise

  digitalWrite(MOTOR_A1, LOW);

  digitalWrite(MOTOR_A2, HIGH);

  //run left motors clockwise

  digitalWrite(MOTOR_B1, HIGH);

  digitalWrite(MOTOR_B2, LOW);

}

else if (analogRead(RIGHT)<=35 && !analogRead(LEFT)<=35) //compare the both sensor to decide the direction

{

  //MOVE RIGHT//

  analogWrite(ENA, 255); //set right motors speed

  analogWrite(ENB, 255); //set left motors speed

  //run right motors clockwise

  digitalWrite(MOTOR_A1, LOW);

  digitalWrite(MOTOR_A2, HIGH);

  //run left motors anti-clockwise

  digitalWrite(MOTOR_B1, LOW);

  digitalWrite(MOTOR_B2, HIGH);

}

else if (!analogRead(RIGHT)<=35 && analogRead(LEFT)<=35) //compare the both sensor to decide the direction

{ 

  //MOVE-LEFT//

  analogWrite(ENA, 255); //set right motors speed

  analogWrite(ENB, 255); //set left motors speed

  //run right motors anti-clockwise

  digitalWrite(MOTOR_A1, HIGH);

  digitalWrite(MOTOR_A2, LOW);

  //run left motors clockwise

  digitalWrite(MOTOR_B1, HIGH);

  digitalWrite(MOTOR_B2, LOW);

}

else if (!analogRead(RIGHT)<=35 && !analogRead(LEFT)<=35) //compare the both sensor to decide the direction

{ 

  //STOP//

  analogWrite(ENA, 0); //set right motors speed

  analogWrite(ENB, 0); //set left motors speed

  //stop right motors

  digitalWrite(MOTOR_A1, LOW);

  digitalWrite(MOTOR_A2, LOW);

  //stop left motors

  digitalWrite(MOTOR_B1, LOW);

  digitalWrite(MOTOR_B2, LOW);

  }

}

3. Understand the Code

• int ENB = 11; //ENB connected to digital pin 11

int MOTOR_A1 = 10; // MOTOR_A1 connected to digital pin 10

• • This section of code at the beginning assigns the pins to their chosen name as variables that will be used later in the code.

• pinMode(ENB, OUTPUT); // initialize ENB pin as an output

pinMode(MOTOR_A1, OUTPUT); // initialize MOTOR_A1 pin as an output

pinMode(RIGHT, INPUT); // initialize RIGHT IR pin as an input

• • The lines set the previously assigned variables to inputs or outputs depending on what will be plugged into them.

• void loop() {

  • Loops set all the code within them to repeat over and over to continue running your program.

• if (analogRead(RIGHT)<=35 && analogRead(LEFT)<=35) //compare the both sensor to decide the direction

{

 //MOVE FORWARD//

     analogWrite(ENA, 100); // set right motors speed

analogWrite(ENB, 100); // set left motors speed

//run right motors clockwise

digitalWrite(MOTOR_A1, LOW);

digitalWrite(MOTOR_A2, HIGH);

//run left motors clockwise

digitalWrite(MOTOR_B1, HIGH);

digitalWrite(MOTOR_B2, LOW);

}

• • This section of code is one of four conditions set for the direction of the vehicle using the logic statements IF, and ELSEIF. They ask the logical question of IF a condition is met with the IR Sensors, then go forward. This requires setting both motors in the same direction and speed.  There are three other logic conditions in this code that set left, right, and stop.

4. Upload and Monitor

• Upload the sketch to the Arduino board. You could add code to Print your IR Sensor values to the Serial Monitor to check that your sensors are working and outputting the right values. This would like like: Serial.println("RIGHT"); for example. 

5. Experiment and Observe

• Build a simple chassis and install the motors, Arduino, LM298M, IR Sensors, and wheels to create the Line Following Robot. This can be out of foam-core, cardboard, or if you're bold enough and have access, laser cut or 3D print one! Test that it works. A good black line to follow can be to use Black Vinyl Electrical Tape.

Considerations:

• Power Supply: Ensure that the power supply can adequately power both the motors and the Arduino. It's common to use separate power supplies for the motors and the logic components. This prevents any voltage drops from the motors from interfering with the microcontroller. 

• Sensor Placement: Properly position the IR proximity sensors to effectively detect the line. Adjust the sensor angles and heights for optimal performance.

• Motor Calibration: Fine-tune the motor control parameters in the code to achieve smooth and precise line following.

• Environmental Factors: Consider variations in lighting conditions, track design, and surface color, and account for these factors in your code.

• Documentation: Keep track of pin connections, code versions, and any modifications made during the development process for future reference.

Questions:

1.  How do the IR Sensors work?

2. Why do you need to use the LM298N instead of directly connecting the motors to the Arduino?