Notice of retraction
Vol. 32, No. 8(2), S&M2292

ISSN (print) 0914-4935
ISSN (online) 2435-0869
Sensors and Materials
is an international peer-reviewed open access journal to provide a forum for researchers working in multidisciplinary fields of sensing technology.
Sensors and Materials
is covered by Science Citation Index Expanded (Clarivate Analytics), Scopus (Elsevier), and other databases.

Instructions to authors
English    日本語

Instructions for manuscript preparation
English    日本語

Template
English

Publisher
 MYU K.K.
 Sensors and Materials
 1-23-3-303 Sendagi,
 Bunkyo-ku, Tokyo 113-0022, Japan
 Tel: 81-3-3827-8549
 Fax: 81-3-3827-8547

MYU Research, a scientific publisher, seeks a native English-speaking proofreader with a scientific background. B.Sc. or higher degree is desirable. In-office position; work hours negotiable. Call 03-3827-8549 for further information.


MYU Research

(proofreading and recording)


MYU K.K.
(translation service)


The Art of Writing Scientific Papers

(How to write scientific papers)
(Japanese Only)

Sensors and Materials, Volume 30, Number 12(3) (2018)
Copyright(C) MYU K.K.
pp. 3021-3028
S&M1738 Research Paper of Special Issue
https://doi.org/10.18494/SAM.2018.1989
Published: December 28, 2018

Relationship between AC/DC Ratio and Light-blocking Structure for Reflective Photoplethysmographic Sensor [PDF]

Hirofumi Nogami, Wataru Iwasaki, Nobutomo Morita and Ryo Takigawa

(Received May 14, 2018; Accepted December 12, 2018)

Keywords: wearable sensor, reflective photoplethysmographic sensor, health-monitoring sysytem

Photoplethysmographic (PPG) sensors are suitable for wearable devices, and they can provide a wide range of information such as stress level (calculated from the heart rate interval), respiration rate, heart rate, and blood vessel stiffness. Of particular importance is that reflective PPG sensors can be easily attached anywhere on the body with low wearer constraint. However, PPG sensors are susceptible to body motion artifacts. The output signal of PPG sensors is composed of alternating current (AC), originating from the heart cycle, and direct current (DC), originating from veins and stationary tissue. Motion artifacts affect DC signals, making it difficult to detect AC signals. Thus, it is important to reduce DC signals and increase the AC/DC ratio. In this study, we investigated the effect of a light-blocking structure on the AC/DC ratio. In addition, the AC/DC ratio was estimated when the gap between the light source (LED) and the photodetector was small (3.2 mm) and large (8.0 mm). In this experiment, the measurement part was a fingertip, and the AC/DC ratio was estimated when AC had the highest output with the force from step-by-step contact. As a result, the AC/DC ratio of the light-blocking structure was 2.4%, and the AC/DC of the non-light-blocking type was 0.9%. Also, the AC/DC of the small-gap PPG sensor was 2.4%, and the AC/DC of the large-gap sensor was 7.5%. Thus, the light-blocking structure was effective in increasing the AC/DC ratio, and a larger distance between the LED and photodetector was useful.

Corresponding author: Hirofumi Nogami


Cite this article
Hirofumi Nogami, Wataru Iwasaki, Nobutomo Morita and Ryo Takigawa, Relationship between AC/DC Ratio and Light-blocking Structure for Reflective Photoplethysmographic Sensor, Sens. Mater., Vol. 30, No. 12, 2018, p. 3021-3028.



Forthcoming Regular Issues


Forthcoming Special Issues

Special issue on Novel Materials and Sensing Technologies on Electronic and Mechanical Devices (2)-1
Guest editor, Teen-Hang Meen (National Formosa University), Wenbing Zhao (Cleveland State University), and Hsien-Wei Tseng (Longyan University)


Special Issue on Materials, Devices, Circuits, and Analytical Methods for Various Sensors (4)
Guest editor, Chien-Jung Huang (National University of Kaohsiung), Cheng-Hsing Hsu (National United University), Ja-Hao Chen (Feng Chia University), and Wei-Ling Hsu (Huaiyin Normal University)
Conference website


Special issue on Novel Materials and Sensing Technologies on Electronic and Mechanical Devices (2)-2
Guest editor, Teen-Hang Meen (National Formosa University), Wenbing Zhao (Cleveland State University), and Hsien-Wei Tseng (Longyan University)


Special Issue on New Trends in Robots and Their Applications
Guest editor, Ikuo Yamamoto (Nagasaki University)


Special Issue on Artificial Intelligence in Sensing Technologies and Systems
Guest editor, Prof. Lin Lin (Dalian University of Technology)
Call for paper


Special issue on Novel Materials and Sensing Technologies on Electronic and Mechanical Devices (3)
Guest editor, Teen-Hang Meen (National Formosa University), Wenbing Zhao (Cleveland State University), and Hsien-Wei Tseng (Longyan University)


Copyright(C) MYU K.K. All Rights Reserved.