Versatile Gas Detection System Based on Combined NDIR Transmission and Photoacoustic Absorption Measurements

Kühn, K.; Pignanelli, E.; Schütze, Andreas

doi:10.1109/jsen.2012.2224104

Cited by 20 publications

(7 citation statements)

References 10 publications

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“…In these cases, selectivity that is basically equal to standard NDIR is achieved using the most simple photoacoustic setup, i.e., a light source illuminating a volume and generating periodic pressure variations. A combined standard NDIR and direct photoacoustic device was presented in [77] and demonstrates a direct comparison. However, commercial examples of direct photoacoustic setups include the recently launched miniature sensors of Sensirion [78], and Infineon [79], the latter including a spectral filter around 4.2 µm to limit cross-sensitivities.…”

Section: Non-resonator Based Setupsmentioning

confidence: 99%

Photoacoustic-Based Gas Sensing: A Review

Palzer

2020

Sensors

104

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The use of the photoacoustic effect to gauge the concentration of gases is an attractive alternative in the realm of optical detection methods. Even though the effect has been applied for gas sensing for almost a century, its potential for ultra-sensitive and miniaturized devices is still not fully explored. This review article revisits two fundamentally different setups commonly used to build photoacoustic-based gas sensors and presents some distinguished results in terms of sensitivity, ultra-low detection limits, and miniaturization. The review contrasts the two setups in terms of the respective possibilities to tune the selectivity, sensitivity, and potential for miniaturization.

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Section: Non-resonator Based Setupsmentioning

confidence: 99%

Photoacoustic-Based Gas Sensing: A Review

Palzer

2020

Sensors

104

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“…Hence, our developed CO 2 measurement device uses an NDIR CO 2 sensor equivalent to COMET [36] to acquire the CO 2 signal. The NDIR sensor absorbs the CO 2 molecules at a specific wavelength (4.3 μm) in the infrared region and follows Beer-Lambert law, as given in equation (1) [37][38][39]. This avoids any recompense when different concentrations of N 2 O, O 2 , anesthetic agents, and water vapor are present in the inspired and expired breath: where I represents the intensity of the light hit on the detector (W cm −2 ), I 0 is the considered intensity of the empty chamber (W cm −2 ), α is the absorption coefficient (cm 2 mol −1 ), b is the concentration of CO 2 (cm 2 mol −1 ), and t is the length of the absorption path (cm).…”

Section: Selection Of Infrared Co 2 Sensormentioning

confidence: 99%

Real-time human respiration carbon dioxide measurement device for cardiorespiratory assessment

2018

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The development of a human respiration carbon dioxide (CO) measurement device to evaluate cardiorespiratory status inside and outside a hospital setting has proven to be a challenging area of research over the few last decades. Hence, we report a real-time, user operable CO measurement device using an infrared CO sensor (Arduino Mega2560) and a thin film transistor (TFT, 3.5″), incorporated with low pass (cut-off frequency, 10 Hz) and moving average (span, 8) filters. The proposed device measures features such as partial end-tidal carbon dioxide (EtCO), respiratory rate (RR), inspired carbon dioxide (ICO), and a newly proposed feature-Hjorth activity-that annotates data with the date and time from a real-time clock, and is stored onto a secure digital (SD) card. Further, it was tested on 22 healthy subjects and the performance (reliability, validity and relationship) of each feature was established using (1) an intraclass correlation coefficient (ICC), (2) standard error measurement (SEM), (3) smallest detectable difference (SDD), (4) Bland-Altman plot, and (5) Pearson's correlation (r). The SEM, SDD, and ICC values for inter- and intra-rater reliability were less than 5% and more than 0.8, respectively. Further, the Bland-Altman plot demonstrates that mean differences ± standard deviations for a set limit were 0.30 ± 0.77 mmHg, -0.34 ± 1.41 mmHg and 0.21 ± 0.64 breath per minute (bpm) for CO, EtCO and RR. The findings revealed that the developed device is highly reliable, providing valid measurements for CO, EtCO, ICO and RR, and can be used in clinical settings for cardiorespiratory assessment. This research also demonstrates that EtCO and RR (r, -0.696) are negatively correlated while EtCO and activity (r, 0.846) are positively correlated. Thus, simultaneous measurement of these features may possibly assist physicians in understanding the subject's cardiopulmonary status. In future, the proposed device will be tested with asthmatic patients for use as an early screening tool outside a hospital setting.

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“…Given the requirements of CO

concentration monitoring clinically, a CO

concentration measurement module has been designed based on the Lambert–Beer law:

where I is the intensity of light striking the detector (I,

is the measured intensity of an empty sample chamber (

), α is the absorption coefficient ( α ,

), C is the CO

concentration ( C ,

) and L is the absorption path length ( L , cm) [ 17 , 27 , 28 ].…”

Section: Innovative Respiratory Monitoring Systemmentioning

confidence: 99%

A Low-Power and Portable Biomedical Device for Respiratory Monitoring with a Stable Power Source

Yang

Chen

Zhou

et al. 2015

Sensors

113

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Continuous respiratory monitoring is an important tool for clinical monitoring. Associated with the development of biomedical technology, it has become more and more important, especially in the measuring of gas flow and CO2 concentration, which can reflect the status of the patient. In this paper, a new type of biomedical device is presented, which uses low-power sensors with a piezoresistive silicon differential pressure sensor to measure gas flow and with a pyroelectric sensor to measure CO2 concentration simultaneously. For the portability of the biomedical device, the sensors and low-power measurement circuits are integrated together, and the airway tube also needs to be miniaturized. Circuits are designed to ensure the stability of the power source and to filter out the existing noise. Modulation technology is used to eliminate the fluctuations at the trough of the waveform of the CO2 concentration signal. Statistical analysis with the coefficient of variation was performed to find out the optimal driving voltage of the pressure transducer. Through targeted experiments, the biomedical device showed a high accuracy, with a measuring precision of 0.23 mmHg, and it worked continuously and stably, thus realizing the real-time monitoring of the status of patients.

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Versatile Gas Detection System Based on Combined NDIR Transmission and Photoacoustic Absorption Measurements

Cited by 20 publications

References 10 publications

Photoacoustic-Based Gas Sensing: A Review

Photoacoustic-Based Gas Sensing: A Review

Real-time human respiration carbon dioxide measurement device for cardiorespiratory assessment

A Low-Power and Portable Biomedical Device for Respiratory Monitoring with a Stable Power Source

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