How to Make Line Following Robot without using Microcontroller

This line following robot operates entirely through analog signal conditioning and feedback control, completely bypassing the need for a microcontroller or programmed software. The system relies on two pairs of IR LEDs acting as transmitters and receivers to detect the contrast between a dark line on the ground and a lighter surface. When the infrared light reflects off the floor, the receiver pair changes its electrical conductivity, altering the voltage input into the circuit. These analog sensor signals are fed into two 10k preset variable resistors, which act as voltage dividers to calibrate the sensitivity threshold for line detection. The adjusted signals are then processed by an LM358 operational amplifier IC, which compares the sensor inputs and drives the subsequent stages. The output of the LM358 is connected to an L293D dual-channel motor driver IC. The L293D acts as a high-current amplifier, supplying the necessary power from the 9V batteries to independently drive the two BO motors and wheels. By continuously monitoring the surface reflectivity, the op-amp rapidly adjusts power to the left and right motors, allowing the chassis to steer itself and successfully track along the path.