Arduino line follower robot with Bluetooth control

Creating a line follower robot is an exciting and educational project, especially when combined with Bluetooth control for enhanced interaction and remote management. The Arduino platform, known for its simplicity and flexibility, makes it easy to design and program a line follower robot that can track a path while being remotely controlled via Bluetooth. In this guide, we’ll explore how to build an Arduino-powered line follower robot and integrate Bluetooth functionality, turning it into an intelligent, remotely-operated device.

What is a Line Follower Robot?

A line follower robot is an autonomous vehicle designed to follow a predetermined path, typically marked by a dark line on a light surface or vice versa. The robot uses sensors to detect the line and adjust its movement accordingly, ensuring it stays on course. Line follower robots are widely used in education and robotics competitions, providing a hands-on way to understand concepts like sensors, motors, and programming.

Components Required for Arduino Line Follower Robot

Before diving into the steps to build the robot, let’s first take a look at the essential components you will need:

Essential Components:

Arduino Board (Uno or Nano) – The brain of your robot.
Bluetooth Module (HC-05 or HC-06) – For wireless control.
IR Sensors – To detect the line.
Motors and Motor Driver (L298N) – To power the wheels.
Chassis and Wheels – The body and movement mechanism.
Power Supply (Battery) – To power the motors and Arduino board.
Jumper Wires and Connectors – For wiring the components together.
Breadboard – For prototype setup (optional).

Setting Up the Chassis and Motors

The first step is assembling the chassis, which will hold the Arduino board, motors, and other components. You can either purchase a pre-made chassis or design your own using lightweight materials like plastic or acrylic.

Attaching Motors to the Chassis

Mount the motors securely on the chassis.
Ensure the wheels are connected to the motors and can rotate freely.
If you’re using a motor driver like the L298N, connect the motors to the driver’s output pins.

Powering the Motors

Use a DC battery or a rechargeable power pack to provide the necessary voltage to the motors.
Connect the power supply to the motor driver and Arduino board to ensure both components receive sufficient power.

Integrating IR Sensors for Line Detection

The core functionality of the line follower robot relies on the ability to detect the line. This is achieved using infrared (IR) sensors. These sensors can distinguish between light and dark surfaces, which is essential for following a line.

Sensor Placement

Place the IR sensors near the front of the robot. Typically, two sensors are used – one on the left and one on the right – to determine the robot’s position relative to the line.
The sensors should be positioned low enough to detect the line on the surface while avoiding obstructions.

Wiring the IR Sensors

Connect the sensors to the analog pins on the Arduino board. This will allow the Arduino to read the values from the sensors and make adjustments based on the detected path.

Programming the Arduino for Line Following

Now that the hardware setup is complete, the next step is to program the Arduino to make the robot follow the line autonomously. The basic idea is to check the sensor readings and adjust the motors based on whether the robot is on the line or off the path.

Simple Line Following Algorithm

Read Sensor Values: Check the sensor readings to determine if the robot is on the line.
Decision Making: Based on the readings, decide whether the robot needs to turn left, right, or continue straight.
Motor Control: Adjust the motors’ speed or direction to ensure the robot follows the line.

cpp

// Basic Arduino code for line following int leftSensor = A0; int rightSensor = A1; int leftMotor = 9; int rightMotor = 10; void setup() { pinMode(leftSensor, INPUT); pinMode(rightSensor, INPUT); pinMode(leftMotor, OUTPUT); pinMode(rightMotor, OUTPUT); } void loop() { int leftValue = digitalRead(leftSensor); int rightValue = digitalRead(rightSensor); if (leftValue == HIGH && rightValue == LOW) { // Turn right digitalWrite(leftMotor, HIGH); digitalWrite(rightMotor, LOW); } else if (leftValue == LOW && rightValue == HIGH) { // Turn left digitalWrite(leftMotor, LOW); digitalWrite(rightMotor, HIGH); } else { // Go straight digitalWrite(leftMotor, HIGH); digitalWrite(rightMotor, HIGH); } }

Adding Bluetooth Control to Your Line Follower Robot

The next step is to integrate Bluetooth control, allowing you to operate the robot remotely using your smartphone. For this, you’ll need to use a Bluetooth module, like the HC-05 or HC-06.

Connecting the Bluetooth Module

TX and RX Pins: Connect the TX (transmit) and RX (receive) pins of the Bluetooth module to the Arduino’s RX and TX pins, respectively.
Power Supply: Ensure that the Bluetooth module is powered through the Arduino’s 5V pin or an external supply.

Configuring the Smartphone App

Download a Bluetooth controller app on your smartphone, such as Bluetooth Serial Controller.
Configure the app to send commands to the Arduino, controlling the motors to move forward, backward, left, or right.

Programming the Arduino for Bluetooth Control

Modify the original line following code to accept commands from the Bluetooth app. The Arduino will read the Bluetooth input and adjust motor movement based on the commands received.

cpp

char command;
int leftMotor = 9;
int rightMotor = 10;
void setup() {
Serial.begin(9600);
pinMode(leftMotor, OUTPUT);
pinMode(rightMotor, OUTPUT);
}
void loop() {
if (Serial.available()) {
command = Serial.read();
if (command == 'F') {
// Move forward
digitalWrite(leftMotor, HIGH);
digitalWrite(rightMotor, HIGH);
}
else if (command == 'B') {
// Move backward
digitalWrite(leftMotor, LOW);
digitalWrite(rightMotor, LOW);
}
else if (command == 'L') {
// Turn left
digitalWrite(leftMotor, LOW);
digitalWrite(rightMotor, HIGH);
}
else if (command == 'R') {
// Turn right
digitalWrite(leftMotor, HIGH);
digitalWrite(rightMotor, LOW);
}
}
}

Testing and Troubleshooting

Once you’ve connected everything and uploaded the code to the Arduino, it’s time to test your robot. Place it on a line track and use the Bluetooth controller to test its movement.

Common Issues and Solutions

Sensors Not Detecting the Line: Check the sensor alignment and ensure they are close enough to the surface.
Bluetooth Not Connecting: Verify the pairing between the Bluetooth module and your smartphone.
Motor Issues: Ensure that the motor wiring is correct and the power supply is sufficient.

Conclusion

Building an Arduino line follower robot with Bluetooth control is a fun and rewarding project that combines hardware and software skills. By integrating sensors, motors, and Bluetooth, you can create an intelligent robot capable of following lines autonomously and responding to remote commands. With this project, you’ll not only learn how to work with Arduino but also gain valuable experience in robotics, sensor integration, and wireless communication.