A Flexible IMU-Based Unit for Validation Studies: A Step Counting Application

Wearable step counting devices, such as smartwatches and activity trackers, have become ubiquitous, embedding sensors like Inertial Measurement Units (IMUs), barometers, and GPS systems to monitor physical activity. Despite their widespread use, these devices often restrict access to raw data, limiting their utility in research. This study introduces a customizable IMU-based unit, designed for flexible data acquisition and integration into a body sensor network (BSN), which can serve as a reference system for validating commercial smartwatches. The IMU-based unit transmits data via the ANT protocol and stores backups on an SD card to mitigate transmission data loss. Five volunteers participated in a protocol involving various conditions, such as resting, walking on a treadmill, walking outdoors, and climbing stairs. Preliminary results indicate that the IMU-based unit detects steps correctly accordingly to the typical waveforms reported in the literature The flexibility of the IMU-based unit allows for extensive post-processing and analysis, making it a valuable tool for validating commercial wearable devices and advancing research in physical activity monitoring. Future improvements include integrating multiple units and adopting Bluetooth Low Energy for enhanced data transmission and compatibility.