• 전기학회논문지P
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• 제59권1호
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• pp.58-63
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• 2010

In this paper, we proposed a wearable respiration measurement system with textile capacitive pressure sensor. Belt typed textile capacitive pressure sensor approach of respiration measurement, from which respiration signatures and rates can be derived in real-time for long-term monitoring, are presented. Belt typed textile capacitive pressure sensor has been developed for this measurement system. the distance change of two plates by the pressure of motion has been used for the respiration measurement in chest area. Respiration rates measured with the textile capacitive pressure sensor was compared with standard techniques on 8 human subjects. Accurate measurement of respiration rate with developed sensor system is shown. The data from the method comparison study is used to confirm theoretical estimates of change in capacitance by the distance change. The current version of respiratory rate detection system using textile capacitive pressure sensor can successfully measure respiration rate. It showed upper limit agreement of $3.7997{\times}10^{-7}$ RPM, and lower limit of agreement of $-3.8428{\times}10^{-7}$ RPM in Bland-Altman plot. From all subject, high correlation were shown(p<0.0001). The proposed measurement method could be used to monitor unconscious persons, avoiding the need to apply electrodes to the directly skin or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using textile capacitive pressure sensor offers a promising possibility of convenient measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range and quality of the rate-finding, broadening the potential application areas of this technology.

• 전기학회논문지
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• 제58권10호
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• pp.2071-2078
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• 2009

In this paper, we proposed a non-contact respiration measurement system with ultrasonic proximity sensor. Ultrasonic proximity sensor approach of respiration measurement which respiration signatures and rates can be derived in real-time for long-term monitoring is presented. 240 kHz ultrasonic sensor has been applied for the proposed measurement system. The time of flight of sound wave between the transmitted signal and received signal have been used for a respiration measurement from abdominal area. Respiration rates measured with the ultrasonic proximity sensor were compared with those measured with standard techniques on 5 human subjects. Accurate measurement of respiration rate is shown from the 50 cm measurement distance. The data from the method comparison study is used to confirm the performance of the proposed measurement system. The current version of respiratory rate detection system using ultrasonic can successfully measure respiration rate. The proposed measurement method could be used for monitoring unconscious persons from a relatively close range, avoiding the need to apply electrodes or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using ultrasonic sensor offers a promising possibility of non-contact measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range of the measurement and quality of the rate-finding for broadening the potential application areas of this technology.

• 센서학회지
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• 제23권2호
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• pp.142-147
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• 2014

Real time driver's respiration monitoring method for detecting driver's drowsiness is investigated. The sensor to obtain driver's respiration signal was a piezoelectric pressure sensor attached at the abdominal region of the seat belt. The resistance of the pressure sensor was changed according to the pressure applied to the seat belt due to the driver's respiration. Monitoring driver's respiration was carried out by driving on the virtual road in a driving simulator from Cheonan to Seoul and monitoring results were compared to the PELCLOS. Experiment results show that the driver's respiration signal can be used for detecting driver's drowsiness.

• 한국정보통신학회논문지
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• 제25권8호
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• pp.1130-1133
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• 2021

In this paper, a miniaturized sensor interface circuit for the respiration detection system is proposed. Respiratory diagnosis is one of the main ways to predict various diseases. The proposed system consists of respiration detection sensor, temperature sensor, and interface circuits. Electrochemical type gas sensor using solid electrolytes is adopted for respiration detection. Proposed system performs sensing, amplification, analog-to-digital conversion, digital signal processing, and i2c communication. And also proposed system has a small form factor and low-cost characteristics through optimization and miniaturization of the circuit structure. Moreover, technique for sensor degradation compensation is introduced to obtain high accuracy. The size of proposed system is about 1.36 cm².

• 감성과학
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• 제21권1호
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• pp.35-44
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• 2018

본 연구에서는 센서의 표면적 변화에 따른 입체적 호흡수 센서의 센싱 방식을 제안하고, 직물 기반의 입체적 호흡수 센서의 성능 평가 및 의복에 적용할 수 있는 디자인 방향성을 탐색하고자 한다. 이를 위해 입체적 구조의 차이에 따라 2가지 유형의 입체적 호흡수 센서를 제작하고 더미와 인체 대상으로 연구를 실시하였다. 연구I은 더미 대상 실험으로 센서의 유형 및 호흡 속도의 연구변인에 의해 입체적 호흡수 센서의 측정 가능성을 탐색하였다. 연구II는 7명의 20대 남성을 대상 실험으로 연구I의 연구변인 이외에 3개의 측정 위치별 적합한 유형의 센서를 제안하였다. 입체적 호흡수 센서의 정확도, 재현성, 신뢰도를 평가하기 위해, 의료기기 분야의 대표적 웨어러블 호흡수 센서인 BIOPAC을 사용하여 입체적 호흡수 센서와 동시에 호흡수를 측정하였다. 이상의 연구 결과를 통해 더미 대상으로 입체적 호흡수 센서의 측정 가능성을 탐색하였으며, 인체 대상으로 호흡수를 측정하여 측정 위치별 적합한 유형의 센서를 제안하였다.

• 한국기계가공학회지
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• 제18권4호
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• pp.100-108
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• 2019

In this paper, a new stacked element pressure sensor has proposed for heartbeat and respiration measurement. This device can be directly attached to an individual's chest; heartbeat and respiration are detected by the pulsatile vibration and deformation of the chest. A key feature of the device is the simultaneous measurement of heart rate and respiration. The structure of the sensor consists of two stacked elements, in which one element includes one polyvinylidene fluoride (PVDF) thin film bonded on polydimethylsiloxane (PDMS) substrate. In addition, for the measurement and signal processing, the electric circuit and the filter are simply constructed with an OP-amp, resistance, and a capacitor. One element (element1, PDMS) maximizes the respiration signal; the other (element2, PVDF) is used to measure heartbeat. Element1 and element2 had sensitivity of 0.163V/N and 0.209V/N, respectively, and element2 showed improved characteristics compared with element1 in response to force. Thus, element1 and element2 were optimized for measuring respiration heart rate, respectively. Through mechanical and vivo human tests, this sensor shows the great potential to optimize the signals of heartbeat and respiration compared with commercial devices. Moreover, the proposed sensor is flexible, light weight, and low cost. All of these characteristics illustrate an effective piezoelectric pressure sensor for heartbeat and respiration measurements.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.334-343
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• 2014

In this paper, we suggest a method to improve the fusion of an accelerometer and gyro sensor by using a Kalman filter to produce a more high-quality respiration signal to supplement the weakness of using a single accelerometer. To evaluate our proposed algorithm's performance, we developed a chest belt-type module. We performed experiments consisting of aerobic exercise and muscular exercises with 10 subjects. We compared the derived respiration signal from the accelerometer with that from our algorithm using the standard respiration signal from the piezoelectric sensor in the time and frequency domains during the aerobic and muscular exercises. We also analyzed the time delay to verify the synchronization between the output and standard signals. We confirmed that our algorithm improved the respiratory rate's detection accuracy by 4.6% and 9.54% for the treadmill and leg press, respectively, which are dynamic. We also confirmed a small time delay of about 0.638 s on average. We determined that real-time monitoring of the respiration signal is possible. In conclusion, our suggested algorithm can acquire a more high-quality respiration signal in a dynamic exercise environment away from a limited static environment to provide safer and more effective exercises and improve exercise sustainability.

• 센서학회지
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• 제16권5호
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• pp.331-336
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• 2007

In this study, we have fabricated an infrared optical fiber based sensor which can monitor the respiration of a patient. The design of a chalcogenide optical fiber based sensor is suitable for insertion into a high electro-magnetic field environment because the sensor consists of low cost and compact mid-infrared components such as an infrared light source, a chalcogenide optical fiber and a thermopile sensor. A fiber-optic respiration sensor is capable of detecting carbon dioxide ($CO_{2}$) in exhalation of a patient using the infrared absorption characteristics of carbon gases. The modulated infrared radiation due to the presence of carbon dioxide is guided to the thermopile sensor via a chalcogenide receiving fiber. It is expected that a mid-infrared fiber-optic respiration sensor which can be developed based on the results of this study would be highly suitable for respiration measurements of a patient during the procedure of an MRI.

• 한국컴퓨터정보학회논문지
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• 제22권11호
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• pp.17-23
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• 2017

In this paper, we implemented a respiration measurement system consisting of piezoelectric sensor, respiration signal processing device, and a viewer on a notebook. We tried an experiment for measuring respiration and detecting sleep apnea syndrome when a subject lay on a bed. We applied the respiration measurement algorithm to sensor data obtained from four subjects. In order to get a good graph shape, data manipulation methods such as moving averages and maximum values were applied. The window size for moving average was chosen as N=70, and the threshold value for each subject was customized. In this case, the proposed system showed 96.0% accuracy. When the maximum value among 90 data was applied instead of moving average, our system achieved 95.1% accuracy. In an experiment for detecting sleep apnea syndrome, the system showed that sleep apnea occurred correctly and calculated the average interval of sleep apnea. While infants or the elderly as well as patients with sleep apnea syndrome are lying down on a bed, our results are also expected to be able to cope with some accidental emergency situation by observing their respiration and detecting sleep apnea.

• 센서학회지
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• 제26권4호
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• pp.280-285
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• 2017

This paper presents a respiration measurement sleeping pillow based on pressure sensors. The respiration measurement sleeping pillow system consists of a sleeping pillow, an interface circuit, a respiration measurement system, and four force-sensitive resistor(FSR) sensors attached at the bottom of the sleeping pillow. The FSR sensors are used to detect the respiration signals induced by the body movement while breathing. The respiration signals of a twenty health man were measured and analyzed by utilizing the respiration measurement sleeping pillow system. The pillow system could detect the respiration signals and had similar characteristics to the chest type BIOPAC respiration sensor used by medical doctors. The respiration rates of ten subjects were also measured. The average measurement accuracy was about 98.8%. The research results showed that this pillow system can be used to detect and analyze the respiration signal when sleeping for the better sleep management.