Elegoo Smart Robot Car - Part 3: Collision Avoidance & Line Following

The Elegoo Smart Robot Car combines mobility with environmental sensing to achieve autonomous navigation on an Arduino Uno platform. At the heart of the system is the Arduino Uno, which executes the control logic and coordinates all inputs and outputs. For movement, the DC motor driver acts as an intermediary, taking low-power control signals from the Arduino and supplying the necessary current to drive the DC motors forward, backward, or in turns. Autonomous collision avoidance relies on the HC-SR04 ultrasonic sensor mounted atop an SG90 servo motor. The servo sweeps the ultrasonic sensor left and right, emitting sound waves and measuring the echo return time to detect obstacles at various angles. When an obstacle is detected within a certain threshold, the Arduino processes this data and commands the motors to alter course. For line tracking, the vehicle uses a dedicated line tracking sensor module mounted underneath the chassis. This module uses infrared emitters and receivers to detect the contrast between a dark track line and a light surface, sending continuous digital or analog feedback to the Arduino. By combining these sensor inputs with the Servo Library in the Arduino IDE, the robot continuously makes real-time steering and speed decisions to avoid crashes or stay precisely on a defined path, powered entirely by an onboard battery pack.