Conveniently implementing a digital smart city equipped with AI functions using a smartphone is not merely about creating a single app; it means building a digital city ecosystem that connects citizens, administrative agencies, transportation systems, safety systems, and environmental management systems by collecting various information generated within the city via smartphone and having AI automatically analyze it. While smart cities of the past were centered around large-scale servers, expensive sensors, and complex infrastructure, the smartphone itself has evolved into a powerful computing device and an AI terminal, ushering in an era where anyone can implement smart city functions at a relatively low cost. Smartphones already possess most of the core functions necessary for urban operations. GPS provides location data, cameras record urban conditions in real time, microphones detect sounds and danger signals, internet connections transmit data to the cloud, and accelerometers and gyroscopes analyze movement status and impacts. When combined with AI technology, intelligent urban management becomes possible that goes beyond simple data collection to understand situations and make automatic judgments. For example, if a citizen photographs road damage with a smartphone, the AI can analyze the size and risk level of the cracks in the image and automatically report it to the relevant agency based on the GPS location. If you upload photos of illegal waste dumping, AI can classify the types of waste and determine cleaning priorities. Smartphone-based AI technology can play a significant role in transportation systems. Anonymously analyzing citizens' movement data allows for the identification of real-time traffic flow in the city, and AI can predict congested areas at specific times to recommend alternative routes. Furthermore, combining bus location data enables AI to calculate arrival times more accurately and predict subway congestion levels. Utilizing smartphone cameras allows for the automatic detection of accident-risk areas by analyzing