Arduino Line Follower Robot Circuit Diagram

Intro: A line follower robot is one of the best first robotics projects: place it on a black line drawn on white paper, switch it on, and it steers itself along the line. It teaches sensors, motor control and simple decision-making in a single afternoon build.
How It Works: Two infrared sensors look down at the floor. A dark line reflects less infrared light than the white surface around it, so each sensor can tell whether it is over the line or not. The Arduino reads both sensors and decides what to do: both sensors on the line means drive straight, only the left sensor on the line means turn left, only the right sensor on the line means turn right, and neither on the line means stop or search slowly.
Components Required: Arduino Uno or Nano board; two IR obstacle or line sensor modules; L298N motor driver module; two DC gear motors with wheels; robot chassis or a small board; battery pack matched to the motor driver (7.4 V is a common example); jumper wires.
Circuit Connections: Left IR sensor output to Arduino digital pin 2, right IR sensor output to digital pin 3, both sensors powered from 5V and GND. L298N inputs to Arduino digital pins 6, 7, 8 and 9, enable pins to pins 10 and 11. Left motor to the driver's first output pair, right motor to the second output pair. Battery pack to the driver's power input, and the driver and Arduino grounds connected together. Follow the L298N module's own guide for its power jumper.
Build Steps: 1. Mount the two sensors at the front, close to the floor and a small distance apart. 2. Wire the sensors, driver and motors as listed. 3. Load a program that reads pins 2 and 3 and drives the motors straight, left, right, or stopped as described above. 4. Draw a thick black line on white paper and test at slow speed first. 5. Adjust the sensor height and the motor speed until the robot follows smooth curves without overshooting.
Troubleshooting: Robot spins in circles: check that the left and right motors are not swapped. Robot ignores the line: lower the sensors closer to the floor and check the sensor adjustment knobs. Motors too weak: check the battery charge and that the driver is receiving power. Jerky movement: lower the speed and add a short delay between sensor reads.
Safety Note: This project uses low-voltage DC only and involves no mains electricity. Keep fingers clear of spinning wheels, do not short the battery terminals, and ask an experienced maker to check the wiring if you are unsure.
Going Further: Try adding a third centre sensor for smoother steering, a buzzer that beeps at junctions, or a speed control that slows the robot on sharp bends. What track will you draw first — a circle, a curve, or a maze? Tell us in the comments.