Evaluating the Accuracy of Low-Cost Wearable Sensors for Healthcare Monitoring

This study evaluates the accuracy of a low-cost wearable system for the continuous monitoring of vital signs, including heart rate, blood oxygen saturation (Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub&g...

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Main Authors: Tatiana Pereira Filgueiras, Pedro Bertemes-Filho, Fabrício Noveletto
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Micromachines
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Online Access:https://www.mdpi.com/2072-666X/16/7/791
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author Tatiana Pereira Filgueiras
Pedro Bertemes-Filho
Fabrício Noveletto
author_facet Tatiana Pereira Filgueiras
Pedro Bertemes-Filho
Fabrício Noveletto
author_sort Tatiana Pereira Filgueiras
collection DOAJ
description This study evaluates the accuracy of a low-cost wearable system for the continuous monitoring of vital signs, including heart rate, blood oxygen saturation (Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula>), blood pressure trend (BPT), and body temperature. The prototype was built using the nRF52840 microcontroller, which integrates photoplethysmography and infrared sensors. The heart rate and Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula> data were collected under three body positions (<i>Rest</i>, <i>Sitting</i>, and <i>Standing</i>), while all measurements were performed using both anatomical configurations: BPT-Finger and BPT-Earlobe. Results were compared against validated commercial devices: UT-100 for heart rate and Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula>, G-TECH LA800 for blood pressure, and G-TECH THGTSC3 for body temperature. Ten participants were monitored over a ten-day period. Bland–Altman analysis revealed clinically acceptable agreement thresholds of ±5 mmHg for blood pressure, ±5–10 bpm for heart rate, ±4% for Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula>, and ±0.5 °C for temperature. Both wearable configurations demonstrated clinically acceptable agreement across all vital signs. The BPT-Earlobe configuration exhibited superior stability and lower variability in the <i>Rest</i> and <i>Sitting</i> positions, likely due to reduced motion artifacts. Conversely, the BPT-Finger configuration showed higher Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula> accuracy in the <i>Standing</i> position, with narrower limits of agreement. These findings highlight the importance of sensor placement in maintaining measurement consistency across physiological conditions. With an estimated cost of only ~USD 130—compared to ~USD 590 for the commercial alternatives—the proposed system presents a cost-effective, scalable, and accessible solution for decentralized health monitoring, particularly in underserved or remote environments.
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spelling doaj-art-83138d7cd29448fd87419640e5ce76992025-08-20T03:08:13ZengMDPI AGMicromachines2072-666X2025-07-0116779110.3390/mi16070791Evaluating the Accuracy of Low-Cost Wearable Sensors for Healthcare MonitoringTatiana Pereira Filgueiras0Pedro Bertemes-Filho1Fabrício Noveletto2Department of Electrical Engineering, Santa Catarina State University, Joinville 89219-710, SC, BrazilDepartment of Electrical Engineering, Santa Catarina State University, Joinville 89219-710, SC, BrazilDepartment of Electrical Engineering, Santa Catarina State University, Joinville 89219-710, SC, BrazilThis study evaluates the accuracy of a low-cost wearable system for the continuous monitoring of vital signs, including heart rate, blood oxygen saturation (Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula>), blood pressure trend (BPT), and body temperature. The prototype was built using the nRF52840 microcontroller, which integrates photoplethysmography and infrared sensors. The heart rate and Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula> data were collected under three body positions (<i>Rest</i>, <i>Sitting</i>, and <i>Standing</i>), while all measurements were performed using both anatomical configurations: BPT-Finger and BPT-Earlobe. Results were compared against validated commercial devices: UT-100 for heart rate and Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula>, G-TECH LA800 for blood pressure, and G-TECH THGTSC3 for body temperature. Ten participants were monitored over a ten-day period. Bland–Altman analysis revealed clinically acceptable agreement thresholds of ±5 mmHg for blood pressure, ±5–10 bpm for heart rate, ±4% for Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula>, and ±0.5 °C for temperature. Both wearable configurations demonstrated clinically acceptable agreement across all vital signs. The BPT-Earlobe configuration exhibited superior stability and lower variability in the <i>Rest</i> and <i>Sitting</i> positions, likely due to reduced motion artifacts. Conversely, the BPT-Finger configuration showed higher Sp<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></semantics></math></inline-formula> accuracy in the <i>Standing</i> position, with narrower limits of agreement. These findings highlight the importance of sensor placement in maintaining measurement consistency across physiological conditions. With an estimated cost of only ~USD 130—compared to ~USD 590 for the commercial alternatives—the proposed system presents a cost-effective, scalable, and accessible solution for decentralized health monitoring, particularly in underserved or remote environments.https://www.mdpi.com/2072-666X/16/7/791wearable sensorshealth monitoringlow-cost devicesphotoplethysmographybiomedical sensor accuracy
spellingShingle Tatiana Pereira Filgueiras
Pedro Bertemes-Filho
Fabrício Noveletto
Evaluating the Accuracy of Low-Cost Wearable Sensors for Healthcare Monitoring
Micromachines
wearable sensors
health monitoring
low-cost devices
photoplethysmography
biomedical sensor accuracy
title Evaluating the Accuracy of Low-Cost Wearable Sensors for Healthcare Monitoring
title_full Evaluating the Accuracy of Low-Cost Wearable Sensors for Healthcare Monitoring
title_fullStr Evaluating the Accuracy of Low-Cost Wearable Sensors for Healthcare Monitoring
title_full_unstemmed Evaluating the Accuracy of Low-Cost Wearable Sensors for Healthcare Monitoring
title_short Evaluating the Accuracy of Low-Cost Wearable Sensors for Healthcare Monitoring
title_sort evaluating the accuracy of low cost wearable sensors for healthcare monitoring
topic wearable sensors
health monitoring
low-cost devices
photoplethysmography
biomedical sensor accuracy
url https://www.mdpi.com/2072-666X/16/7/791
work_keys_str_mv AT tatianapereirafilgueiras evaluatingtheaccuracyoflowcostwearablesensorsforhealthcaremonitoring
AT pedrobertemesfilho evaluatingtheaccuracyoflowcostwearablesensorsforhealthcaremonitoring
AT fabricionoveletto evaluatingtheaccuracyoflowcostwearablesensorsforhealthcaremonitoring