The escalating water crisis, intensified by climate change and inefficient irrigation practices, highlights the urgent need for innovative solutions in agriculture. This paper presents a design thinking-driven approach to developing an IoT-based smart irrigation system for sustainable precision agriculture. The system integrates real-time data collection from humidity and temperature sensors deployed via a mobile robotic platform, combined with weather forecast APIs to enable data-driven irrigation scheduling tailored to plant-specific requirements. The proposed architecture consists of four interconnected layers: Sensor, Edge, Cloud, and Application. Sensor data is transmitted via MQTT protocols to a Firebase-powered cloud infrastructure, while a ReactJS dashboard provides farm managers with real-time monitoring, automated alerts, and irrigation control. The paper documents the design thinking process, multidisciplinary collaboration challenges, and lessons learned from early field testing. K