Design of an ESP32-Instrumentation Device for Data Acquisition and Wireless Monitoring of Human Foot Pronation

Abstract

This paper presents the design and experimental prototyping of a low-cost ESP32-based wireless instrumentation device for real-time acquisition and monitoring of human foot pronation. The system integrates five FSR 402 force sensors into a smart cotton sock, interfaced with an ESP32-WROOM-32 microcontroller. A rule-based classification algorithm analyzes sensor activation patterns to distinguish neutral pronation, over-pronation, under-pronation, and error states. Pronation data is transmitted wirelessly via Bluetooth to an Android smartphone running the Serial Bluetooth Terminal application. Experimental validation on three human subjects with clinically confirmed neutral, over-pronated, and under-pronated foot types demonstrated 100% classification accuracy under normal walking conditions. The system achieves wireless transmission latency below 100ms, reliable operation up to 10 meters line-of-sight, and over 4 hours of continuous operation on a 2000mAh power bank. Total material cost is under $25 USD. The device offers a non-invasive, portable, and reproducible solution for biomechanical monitoring in sports medicine, physiotherapy, and home-based rehabilitation.