We used to see more and more projects where the microcontroller is a must part. This leaves of board those who like things to understandable and straightforward. This line following robot relies only on analog electronics which allows the robot to sense dark line and follow it. Schematic relies on bunch transistors that act as switches when the black color of the line is sensed with phototransistors.
Robot base is built of wood where a simple DC motor with gearbox is attached. The design is similar to tank with threads. Threads are kept shorter as possible to make it more mobile. As result line following Robot does its job great – you need to draw black lines to keep it going.