Energy conservation and environmental safety are critical issues in indoor environments, where intelligent sensing and control systems can play a pivotal role. In this work, we present an Arduino-based energy-saving lighting and safety monitoring system with integrated multiple sensor modules and relevant electronic components. The proposed system employs a light intensity sensor to detect ambient light and adaptively regulate the brightness of an RGB LED matrix and automatically open or close the curtain, thereby maximizing the use of natural light and reducing power consumption. For environmental safety, a temperature and humidity sensor and a flame sensor are incorporated to monitor surrounding conditions. The system responds by adjusting fan speed based on temperature and humidity conditions to balance comfort and energy efficiency. Moreover, it responds by activating an alarm device and a warning light and opening the curtain when fire hazards are detected. In addition, an infrared receiver and a remote controller allow the manual control of these operations. Experimental results indicate the potential of the proposed system to reduce energy consumption while maintaining comfort and safety. This research highlights the practical application of sensor technologies and low-cost materials in developing a scalable, energy- and safety-aware indoor monitoring system.