Circuit Connections

Single IR Sensor Line Follower Robot

🎯 Lesson Objective

In this lesson, students will learn:

• How to connect the IR sensor to the ESP32
• How to connect the L298N motor driver to the ESP32
• How to connect the DC motors to the motor driver
• How to properly supply power to the robot system

By the end of this lesson, students will be able to correctly wire all the components required for the Single IR Sensor Line Follower Robot.

1️⃣ IR Sensor Connection

The IR sensor is responsible for detecting the black line on the surface.

The sensor has three pins:

• VCC – Power supply
• GND – Ground connection
• OUT – Signal output

Connection with ESP32

VCC → 3.3V (ESP32)
GND → GND (ESP32)
OUT → GPIO 34 (ESP32)

The OUT pin sends a digital signal to the ESP32 indicating whether the sensor detects a black or white surface.

2️⃣ Motor Driver Connection (L298N)

The L298N motor driver controls the movement and direction of the DC motors.

The ESP32 sends control signals to the motor driver through input pins.

L298N Control Pins

IN1 → GPIO 26 (ESP32)
IN2 → GPIO 27 (ESP32)
IN3 → GPIO 14 (ESP32)
IN4 → GPIO 12 (ESP32)

These pins control the direction of both motors.

3️⃣ DC Motor Connections

Two DC motors are connected to the motor driver.

Motor A (Left Motor)

Motor wires → OUT1 and OUT2 of L298N

Motor B (Right Motor)

Motor wires → OUT3 and OUT4 of L298N

These connections allow the motor driver to control both motors independently.

4️⃣ Power Supply Connections

The robot requires power for both the motors and the microcontroller.

Motor Driver Power

Battery Positive → 12V terminal of L298N
Battery Ground → GND of L298N

ESP32 Power

ESP32 can be powered using:

• USB cable
or
• External 5V supply

Make sure all grounds are connected together.

Common Ground Connections:

ESP32 GND → L298N GND → Battery GND

This is important for proper communication between components.

5️⃣ Circuit Summary

Below is a quick summary of all connections used in this project.

IR Sensor

VCC → 3.3V
GND → GND
OUT → GPIO 34

Motor Driver Control

IN1 → GPIO 26
IN2 → GPIO 27
IN3 → GPIO 14
IN4 → GPIO 12

Motors

Left Motor → OUT1 & OUT2
Right Motor → OUT3 & OUT4

Power

Battery → L298N
ESP32 → USB or 5V supply

6️⃣ Important Wiring Tips

To ensure the robot works correctly, follow these tips:

✔ Double-check all wiring connections
✔ Ensure the battery polarity is correct
✔ Make sure all GND connections are common
✔ Place the IR sensor facing downward toward the ground
✔ Keep the sensor about 1–2 cm above the surface

Proper wiring is essential for reliable robot performance.

🚀 What Happens Next

Now that all components are connected correctly, the next step is to write the program that controls the robot’s movement.