Arduino microcontroller, Motion-activated lighting, Energy efficiency, Automation This paper explores the design, development, and implementation of an energy-efficient motion-activated lighting system utilizing an Arduino microcontroller. The primary objective is to automate lighting control by ensuring lights activate only when motion is detected and turn off after a predefined period of inactivity. This approach minimizes unnecessary energy consumption and promotes sustainability. The Arduino platform serves as the central control unit, offering a customizable framework for managing sensor input and controlling lighting output. This system is adaptable for various applications, including residential, commercial, and industrial environments. By integrating PIR sensors and relay modules, the system enhances automation and efficiency. Furthermore, the system's potential applications extend to smart city infrastructure and sustainable energy conservation initiatives.