Fryderyk GAJDZIK, Michal KIMBAR and Pawel KROWICKI
Wrocław University of Science and Technology, Faculty of Mechanical Engineering, Wroclaw, Poland
Mobile biomedical telemetry systems require more than a user-facing application for displaying sensor values.
In practical acquisition scenarios, the mobile device must also act as an edge client that mediates between a constrained Bluetooth Low Energy sensor and a backend service while preserving data continuity under intermittent network conditions. This paper presents the design of a prototype Android-based edge client for session-oriented ECG telemetry acquisition. The aim is to organize the mobile layer as a resilient acquisition component responsible for BLE connectivity, acquisition control, packet parsing, real-time preview, local buffering, session registration, and deferred synchronization with a FastAPI edge backend. The proposed architecture combines a binary BLE frame format with sequence numbering, an offline-first local persistence strategy, CSV storage for raw session samples, and a Room database used as a session metadata registry and synchronization queue. The main contribution is an engineering design that separates the visualization path from the raw-data persistence path and treats the smartphone as a local edge buffer rather than only a display terminal. The work is limited to software architecture and functional verification of the prototype data flow. It does not include clinical validation, diagnostic performance evaluation, or certification as
a medical device.