Wireless System of FSR Sensors Encapsulated in Medical Silicone for the Diagnosis of Pressure Points in Diabetic Patients with Transtibial Amputation

Huaman I.; Martinez J.; Tito A.; Cabezas F. · C3 2025 - IEEE Colombian Caribbean Conference (2025) · DOI: 10.1109/c366505.2025.11340129

Resumen

Diabetes mellitus is a frequent cause of transtibial amputation, requiring precise fitting of the prosthesis to avoid ulcers and complications. The lack of diagnostic tools to identify critical pressures increases clinical risk and costs. In countries such as Peru, the price of a silicone prosthetic liner can exceed US$300, making it difficult to acquire. Faced with this reality, a wireless sensorized system capable of detecting pressure points effectively and affordably is proposed. The system acts as direct interface between the residual limb and the prosthesis, simulating real conditions of use. It uses FSR 402 sensors encapsulated in vacuum-cured medical silicone, connected to an ESP32 microcontroller that transmits data via WiFi to an interface developed in MATLAB. The platform allows visualizing pressures on a 3D model of the liner, identifying risk zones and recording data in CSV files. The results validate the technical feasibility of the prototype. The use of an operational amplifier increased the signal similarity to an ideal step by 58 %, improving stability. The silicon coated sensors showed a reduction in pressure values compared to the sensors without encapsulation. Even so, both cases presented a good fit to the logarithmic model, with low RMSE errors (24.20 with silicone and 25.25 without silicone) preserving a stable behavior. In addition, the average latency was 101.8 ± 6.0 ms, below the human perceptible threshold, allowing a real-time response. This system represents a practical, economical and adaptable solution for the clinical follow-up of patients with transtibial amputation due to diabetes.

Instituciones: Universidad Nacional Mayor de San Marcos