The Analogue PID Line-Following Robot is a high-speed autonomous robot designed to accurately follow a black line on a contrasting surface using a fully analogue control system. Unlike conventional line followers that rely on microcontrollers and software-based algorithms, this robot performs all sensing, error calculation, and PID control using operational amplifiers, resistors, capacitors, and potentiometers, resulting in extremely fast real-time response with virtually no computational delay.

The robot uses an array of infrared reflective sensors to continuously detect the position of the line. These sensor signals are processed through analogue signal-conditioning circuits to generate an error voltage representing the robot’s deviation from the track center. This error signal is then fed into an analogue PID controller consisting of proportional, integral, and derivative stages. The proportional stage provides immediate correction, the integral stage eliminates accumulated tracking errors, and the derivative stage predicts future deviations to improve stability and reduce oscillations.

The controller output drives a differential motor control system, adjusting the speed of the left and right motors to maintain precise alignment with the track. A custom-designed PCB integrates the sensor interface, PID circuitry, gain-adjustment potentiometers, and motor driver connections into a compact and reliable platform. This project demonstrates the practical application of classical control theory through hardware-based computation while achieving smooth, stable, and high-performance line-following behaviour.