Rice is one of the most important staple crops in the world, serving as the primary food source for over 50% of the global population and accounting for 21% of the world’s total food supply. This study centers on improving eco-friendly field management for small-scale farmers, with a focus on enhancing pest and weed control in rice paddies. Although chemical pesticide spraying offers quick results, its long-term use has adverse effects on soil and human health, and it often fails to eliminate pests completely—potentially contributing to pesticide resistance. Drawing from market research, field observations, and farmer surveys, this project integrates Internet of Things (IoT) and smart agriculture technologies with the advantages of computer-aided design (CAD) tools to quickly test and adjust various design solutions in real time. The final design, refined through a combination of sketch ideation and 3D simulation, significantly improves both the efficiency and accuracy of the product, resulting in an intelligent solution. This system enables farmers to monitor pest and weed conditions in real time and automatically execute precise control operations, thereby reducing resource consumption. Looking ahead, the system’s modular functions can be further optimized for broader applications—such as managing other crops or integrating additional smart devices (e.g., drones) to boost overall operational efficiency. This intelligent solution offers a new approach to global food security and sustainable agriculture, with particular relevance to rice production.