C4-Based Software Architecture Modeling for Drone-Based Mechatronic System for High-Altitude Fire Surveillance

Fire remains a major hazard in urban environments, where high-rise buildings pose unique challenges for evacuation and firefighting. This paper presents the design of a drone-based system capable of deploying fire-extinguishing spheres and performing real-time person detection using the YOLOX algorithm. The system integrates mechanical, electronic, and computational components into a modular unit that can be mounted on a commercial drone platform. The software architecture was modeled using the C4 methodology and deployed on Microsoft Azure, incorporating services such as Azure App Service, Azure IoT Hub, Azure Cosmos DB, Azure Functions, Azure Blob Storage, and Azure Machine Learning, in combination with Mux for video streaming. A virtual prototype was tested using Wokwi, validating six use cases: authentication, telemetry ingestion, command transmission, telemetry visualization, video playback, and object detection. The results confirmed reliable operation with acceptable latencies, demonstrating the feasibility of cloud-integrated firefighting drones for enhancing safety in high-rise urban environments.