Development of a Self-Powered Piezo-Resistive Smart Insole Equipped with Low-Power BLE Connectivity for Remote Gait Monitoring

The evolution of low power electronics and the availability of new smart materials are opening new frontiers to develop wearable systems for medical applications, lifestyle monitoring, and performance detection. This paper presents the development and realization of a novel smart insole for monitori...

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Main Authors: Roberto de Fazio, Elisa Perrone, Ramiro Velázquez, Massimo De Vittorio, Paolo Visconti
Format: Article
Language:English
Published: MDPI AG 2021-07-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/21/13/4539
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author Roberto de Fazio
Elisa Perrone
Ramiro Velázquez
Massimo De Vittorio
Paolo Visconti
author_facet Roberto de Fazio
Elisa Perrone
Ramiro Velázquez
Massimo De Vittorio
Paolo Visconti
author_sort Roberto de Fazio
collection DOAJ
description The evolution of low power electronics and the availability of new smart materials are opening new frontiers to develop wearable systems for medical applications, lifestyle monitoring, and performance detection. This paper presents the development and realization of a novel smart insole for monitoring the plantar pressure distribution and gait parameters; indeed, it includes a piezoresistive sensing matrix based on a Velostat layer for transducing applied pressure into an electric signal. At first, an accurate and complete characterization of Velostat-based pressure sensors is reported as a function of sizes, support material, and pressure trend. The realization and testing of a low-cost and reliable piezoresistive sensing matrix based on a sandwich structure are discussed. This last is interfaced with a low power conditioning and processing section based on an Arduino Lilypad board and an analog multiplexer for acquiring the pressure data. The insole includes a 3-axis capacitive accelerometer for detecting the gait parameters (swing time and stance phase time) featuring the walking. A Bluetooth Low Energy (BLE) 5.0 module is included for transmitting in real-time the acquired data toward a PC, tablet or smartphone, for displaying and processing them using a custom Processing<sup>®</sup> application. Moreover, the smart insole is equipped with a piezoelectric harvesting section for scavenging energy from walking. The onfield tests indicate that for a walking speed higher than 1 ms<sup>−1</sup>, the device’s power requirements (i.e., <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mover><mi mathvariant="normal">P</mi><mo>¯</mo></mover><mo>=</mo><mn>5.84</mn><mtext> </mtext><mi>mW</mi></mrow></semantics></math></inline-formula>) was fulfilled. However, more than 9 days of autonomy are guaranteed by the integrated 380-mAh Lipo battery in the total absence of energy contributions from the harvesting section.
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spelling doaj.art-1a4297cb441b452293da254ab7db6bd52023-11-22T02:50:48ZengMDPI AGSensors1424-82202021-07-012113453910.3390/s21134539Development of a Self-Powered Piezo-Resistive Smart Insole Equipped with Low-Power BLE Connectivity for Remote Gait MonitoringRoberto de Fazio0Elisa Perrone1Ramiro Velázquez2Massimo De Vittorio3Paolo Visconti4Department of Innovation Engineering, University of Salento, 73100 Lecce, ItalyDepartment of Innovation Engineering, University of Salento, 73100 Lecce, ItalyFacultad de Ingeniería, Universidad Panamericana, Aguascalientes 20290, MexicoDepartment of Innovation Engineering, University of Salento, 73100 Lecce, ItalyDepartment of Innovation Engineering, University of Salento, 73100 Lecce, ItalyThe evolution of low power electronics and the availability of new smart materials are opening new frontiers to develop wearable systems for medical applications, lifestyle monitoring, and performance detection. This paper presents the development and realization of a novel smart insole for monitoring the plantar pressure distribution and gait parameters; indeed, it includes a piezoresistive sensing matrix based on a Velostat layer for transducing applied pressure into an electric signal. At first, an accurate and complete characterization of Velostat-based pressure sensors is reported as a function of sizes, support material, and pressure trend. The realization and testing of a low-cost and reliable piezoresistive sensing matrix based on a sandwich structure are discussed. This last is interfaced with a low power conditioning and processing section based on an Arduino Lilypad board and an analog multiplexer for acquiring the pressure data. The insole includes a 3-axis capacitive accelerometer for detecting the gait parameters (swing time and stance phase time) featuring the walking. A Bluetooth Low Energy (BLE) 5.0 module is included for transmitting in real-time the acquired data toward a PC, tablet or smartphone, for displaying and processing them using a custom Processing<sup>®</sup> application. Moreover, the smart insole is equipped with a piezoelectric harvesting section for scavenging energy from walking. The onfield tests indicate that for a walking speed higher than 1 ms<sup>−1</sup>, the device’s power requirements (i.e., <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mover><mi mathvariant="normal">P</mi><mo>¯</mo></mover><mo>=</mo><mn>5.84</mn><mtext> </mtext><mi>mW</mi></mrow></semantics></math></inline-formula>) was fulfilled. However, more than 9 days of autonomy are guaranteed by the integrated 380-mAh Lipo battery in the total absence of energy contributions from the harvesting section.https://www.mdpi.com/1424-8220/21/13/4539smart insolehealth monitoringplantar pressure distributionpiezoresistivityBLE
spellingShingle Roberto de Fazio
Elisa Perrone
Ramiro Velázquez
Massimo De Vittorio
Paolo Visconti
Development of a Self-Powered Piezo-Resistive Smart Insole Equipped with Low-Power BLE Connectivity for Remote Gait Monitoring
Sensors
smart insole
health monitoring
plantar pressure distribution
piezoresistivity
BLE
title Development of a Self-Powered Piezo-Resistive Smart Insole Equipped with Low-Power BLE Connectivity for Remote Gait Monitoring
title_full Development of a Self-Powered Piezo-Resistive Smart Insole Equipped with Low-Power BLE Connectivity for Remote Gait Monitoring
title_fullStr Development of a Self-Powered Piezo-Resistive Smart Insole Equipped with Low-Power BLE Connectivity for Remote Gait Monitoring
title_full_unstemmed Development of a Self-Powered Piezo-Resistive Smart Insole Equipped with Low-Power BLE Connectivity for Remote Gait Monitoring
title_short Development of a Self-Powered Piezo-Resistive Smart Insole Equipped with Low-Power BLE Connectivity for Remote Gait Monitoring
title_sort development of a self powered piezo resistive smart insole equipped with low power ble connectivity for remote gait monitoring
topic smart insole
health monitoring
plantar pressure distribution
piezoresistivity
BLE
url https://www.mdpi.com/1424-8220/21/13/4539
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