The Arduino-Based Line-Following Robot with Automated Alcohol Spraying Mechanism is an autonomous mobile system designed to perform consistent surface spraying along predefined indoor paths. The robot navigates using infrared sensors to detect line contrast, while color sensors trigger specific actions, including movement and activation of a servo-controlled dual-nozzle spraying mechanism. Passive Infrared (PIR) sensors ensure safe operation by temporarily inhibiting spraying when human motion is detected. Its structure features a motorized base housing the electronics, sensors, and pumps, combined with 3D-printed components for lightweight construction, ease of customization, and rapid prototyping. Coordinated by an Arduino microcontroller, the system integrates navigation, actuation, and safety functions using simple sensor-driven logic. The design emphasizes accessibility, low-cost implementation, and reliable performance, providing a practical platform for automation, prototyping, and educational applications in structured indoor environments. 

Keywords: Arduino, line-following, automated spraying.