Robotics·Jan 1, 2022

Line Follower Robot

A PID-style line follower built for competition tracks — the one that won 1st at the SAGC 4th Science Festival.

Overview

Line followers look easy and behave easy until you push the speed up. Then suddenly the robot starts shooting off the track on tight turns and you remember why control theory exists. I built this one for competition. It uses an IR array on the track and a differential drive, with the firmware reading the array, estimating position, and trimming the motor PWM to keep the robot smooth at speed.

Specifications

RoleRobot builder and tuner

MicrocontrollerArduino UNO

SensorsIR sensor array

ModulesMotor driverDC gear motors

ProtocolsGPIOPWM

Tech tagsLine FollowerPID ControlIR Sensor ArrayArduinoCompetition Robot

Architecture

Sensor array estimates line position. Firmware converts position error into left/right motor speed corrections.

Project photos

Line follower robot side view — Robot detail

Implementation details

Firmware

Firmware reads the IR array, calculates line position, adjusts motor PWM, and tunes response for curves and intersections.

Power

Battery selection and motor current capability affect speed and stability.

Components / BOM

Arduino UNO, IR sensor array, Motor driver, DC gear motors, Battery pack

Engineering challenges

High-speed turns and clean transitions through intersections without losing the line.

Solutions

Sensor calibration on the real track, careful PID tuning, and small tweaks to the wheelbase and weight to keep the robot stable.

Results & metrics

1st position in the line-follower competition at the SAGC 4th Science Festival.

Future improvements

Encoders for closed-loop wheel control, a small telemetry channel, a modular chassis and auto-calibration before each run.