What is the simplest robot I can build?

The simplest robot you can build is a basic line-following robot, which typically consists of a small chassis, two wheels, a motor, a power source (like batteries), and light sensors. The sensors detect the line on the ground, and the motors adjust the wheels' movement to keep the robot following the line. This project requires minimal components and basic programming skills, making it accessible for beginners. You can find many tutorials online to guide you through the building process.