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Infrared sensors are the fastest growing segment of a $1 billion a year temperature sensor market. Matt Guerreiri of Raytek explains why.
Output stability or drift overtime has long been a major performance deficiency for gas sensors irrespective of what technology or methodology is used for their conception…
Abstract
Purpose
Output stability or drift overtime has long been a major performance deficiency for gas sensors irrespective of what technology or methodology is used for their conception. Software correction may alleviate the problem somewhat but it is not always applicable. It has long been the objective of many researchers in this field to overcome this problem fundamentally and for good. The purpose of this paper is to show that this objective has now finally been achieved.
Design/methodology/approach
Conventional non‐dispersive infrared (NDIR) dual beam methodology utilizes the ratio of signal channel output over reference channel output for signal processing. The signal filter overlaps the absorption band of the gas of interest while the reference filter does not. However, this ratio changes as the source ages. The current methodology uses an absorption bias between signal and reference channel outputs. This absorption bias is created by using a path length for the signal channel greater than that for the reference channel. Both the signal and reference detectors carry an identical spectral filter overlapping the absorption band of the gas to be measured.
Findings
Implementation of the currently patented NDIR gas‐sensing methodology has been carried out in different gas sensor configurations for over a year in the laboratory. Performance results for these sensors showing insignificant output drifts overtime have been repeatedly demonstrated via simulated aging for the source.
Originality/value
The paper puts forward the view that the recent breakthrough of the Near Zero Drift methodology for NDIR gas sensors will very quickly change the hierarchy of technology dominance and utility for gas sensors at large.
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Keywords
The purpose of this paper is to acquaint a wide audience of readers with some of the unique remote sensing and navigation capabilities of animals.
Abstract
Purpose
The purpose of this paper is to acquaint a wide audience of readers with some of the unique remote sensing and navigation capabilities of animals.
Design/methodology/approach
Biomimetic comparison of remote sensors evolved by animals and sensors designed by man. The study and comparison includes thermal infrared sensors used by snakes, echolocation used by bats and dolphins, and navigation methods used by birds. Countermeasures used by prey to avoid capture are also considered.
Findings
Some animals have remote sensing and navigation capabilities that are considerably more efficient than those provided by the human body or designed by man.
Practical implications
Sensor designers may be encouraged to use the biometic approach in the design of new sensors.
Social implications
The paper provides a better understanding of animal behaviour, especially their unique abilities to remotely sense, echolocate and navigate with high accuracy over considerable distances.
Originality/value
The paper presents a comparison of remote sensors used by animals with those developed by humans. Remote sensor designers can learn to improve their sensor designs by studying animal sensors within a biomimetic framework.
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Looks at the use of infrared sensors, noting that they fall into the two basic groups of quantum and thermal devices. Focuses on quantum devices and their further subdivision into…
Abstract
Looks at the use of infrared sensors, noting that they fall into the two basic groups of quantum and thermal devices. Focuses on quantum devices and their further subdivision into photoconductive and photovoltaic types. Notes that thermal devices also fall into two categories: those relying on the Seebeck effect, and those known as ferroelectrics. Looks at the use of ferroelectric materials in pyrometry. Concludes by noting the advantages of some of the various types of system.
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Thilo Kahl, Herbert Bousack, Erik S. Schneider and Helmut Schmitz
Early detection of forest fires offers the chance to put the fire out before it gets out of control. The purpose of this paper is to look into nature and to learn how certain…
Abstract
Purpose
Early detection of forest fires offers the chance to put the fire out before it gets out of control. The purpose of this paper is to look into nature and to learn how certain insects detect remote forest fires. A small group of highly specialized insects that have been called pyrophilous is attracted by forest fires and approaches fires sometimes from distances of many kilometers. As a unique feature some of these insects are equipped with infrared (IR) receptors, which in case of two species of jewel beetles (family Buprestidae) are used for fire detection.
Design/methodology/approach
The paper has investigated the IR receptors of the pyrophilous beetles with various morphological techniques including scanning electron microscopy, transmission electron microscopy, neuroanatomy and the paper also investigated the thermo-/mechanical properties of the IR receptors by nanoindentation. Data were used for subsequent modeling of a biomimetic technical sensor. Finally, a macroscopic prototype was built and tested.
Findings
This biological principle was transferred into a new kind of uncooled technical IR receptor. A simple model for this biological IR sensor is a modified Golay sensor in which the gas has been replaced by a liquid. Here, the absorbed IR radiation results in a pressure increase of the liquid and the deflection of a thin membrane. For the evaluation of this model, analytical formulas are presented, which permits the calculation of the pressure increase in the cavity, the deformation of the membrane and the time constant of an artificial leak to compensate ambient temperature changes. Some organic liquids with high thermal expansion coefficients may improve the deflection of the membrane compared to water.
Originality/value
Results so far obtained suggest that it seems promising to take the photomechanic IR receptors of pyrophilous jewel beetles as models for the building of new uncooled IR sensors. The beetle receptors have been shaped by evolution since thousands of years and, therefore, can be considered as highly optimized sources of inspiration for new technical sensors suitable for remote fire detection.
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Jacob Wong and Chi Tse
The output of nearly all non‐dispersive infrared (NDIR) gas sensors deployed in the heating, ventilation, and air conditioning (HVAC) industry today cannot maintain their accuracy…
Abstract
Purpose
The output of nearly all non‐dispersive infrared (NDIR) gas sensors deployed in the heating, ventilation, and air conditioning (HVAC) industry today cannot maintain their accuracy specifications within six months to a year. Consequently, all installed NDIR gas sensors must be re‐checked for accuracy over time at great costs. The purpose of this paper is to advance a novel technique for expeditiously recalibrating such installed NDIR gas sensors without the need for using any gas standards.
Design/methodology/approach
By recognizing the fact that the calibration curve for absorption biased designed NDIR gas sensors comprises two distinct domains, namely an invariant NDIR absorption physics domain and a variant sensor components characteristics domain. By formulating a novel recalibration procedure which corrects only changes that have taken place in the variant sensor components characteristics domain over time, it is possible to recalibrate the sensor very rapidly and remotely via wireless or infrared means using only the gas concentration level surrounding the sensor as a reasonably accurate gas standard.
Findings
Implementation of the currently described recalibration technique to a large number of absorption biased designed NDIR gas sensors has been carried out for over a year in the laboratory. Results of these experiments have unambiguously confirmed the capability and the accuracy of this novel recalibration technique.
Originality/value
The currently presented recalibration technique for absorption biased designed NDIR gas sensors is original and has never been published elsewhere. This technique significantly reduces the maintenance costs, inclusive of labor and material, for installed NDIR gas sensors that require periodic and mandatory accuracy commissioning over time.
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Yusman, Aidi Finawan and Rusli
Purpose – The purpose of this research is to design and build a wild animal pest repellent device with combination of passive infrared (PIR) sensor and ultrasonic signal based on…
Abstract
Purpose – The purpose of this research is to design and build a wild animal pest repellent device with combination of passive infrared (PIR) sensor and ultrasonic signal based on microcontroller as system controller. The PIR sensor is used to detect the presence of wild animal objects and ultrasonic signals to interfere with the hearing.
Design/Methodology/Approach – The design of the system is built based on microcontroller as the system controller. The system as a whole includes hardware and software. The design of hardware consists of the system design on the transmitter side and the system design on the receiver side, while the software in the of system are algorithms using C language programming.
Findings – The resulting repellent device can detect animals approaching up to a distance of 5 m and may interfere with its hearing with a 40 kHz ultrasonic frequency up to a distance of 20 m. The system also uses remote monitoring devices using 433 MHz radio frequency up to a distance of 60 m.
Research Limitations/Implications – Each animal has different hearing frequencies, as well as some wild animals, but the hearing frequencies of wild animals are generally at ultrasonic frequencies. The frequency of animal hearing may vary from audio frequency to ultrasonic frequency, so ultrasonic wave emission testing with varying frequencies is required.
Practical Implications – This research combines systems on transmitters and receivers, with real-time monitoring of wild animal positions, and it can be possible to monitor the position of more detailed animals by installing more types of sensors as well as increasing the number of sensors.
Originality/Value – This paper may provide additional insight into the hearing frequencies of animals and may also serve as comparable papers for similar studies.
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Summarizes some of the most commonly used gas sensors and describes howeach one works. Covers solid state gas sensors; aqueous electrochemicalgas sensors; paramagnetic gas sensors…
Abstract
Summarizes some of the most commonly used gas sensors and describes how each one works. Covers solid state gas sensors; aqueous electrochemical gas sensors; paramagnetic gas sensors, photometric gas sensors; thermal conductivity gas sensors and fibre‐optic gas sensors.
K. Balachander, C. Venkatesan and Kumar R.
Autonomous vehicles rely on IoT-based technologies to take numerous decisions in real-time situations. However, added information from the sensor readings will burden the system…
Abstract
Purpose
Autonomous vehicles rely on IoT-based technologies to take numerous decisions in real-time situations. However, added information from the sensor readings will burden the system and cause the sensors to produce inaccurate readings. To overcome these issues, this paper aims to focus on communication between sensors and autonomous vehicles for better decision-making in real-time. The system has unique features to detect the upcoming and ongoing vehicles automatically without intervention of humans in the system. It also predicts the type of vehicle and intimates the driver.
Design/methodology/approach
The system is designed using the ATmega 328 P and ESP 8266 chip. Information from ultrasonic and infrared sensors are analyzed and updated in the cloud server. The user can access all these real-time data at any point of time. The stored information in cloud servers is used for integrating artificial intelligence into the system.
Findings
The real-time sensor information is used to predict the surrounding environment and the system responds to the user according to the situation.
Practical implications
The system is implemented on embedded platform with IoT technology. The sensor information is updated to the cloud using the Blynk application for the user in real time.
Originality/value
The system is proposed for smart cities with IoT technology where the user and the system are aware of the surrounding environment. The system is mainly concerned with the accuracy of sensors and the distance between the vehicles in real-time environment.
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Jinyi Li, Zhenhui Du, Zheyuan Zhang, Limei Song and Qinghua Guo
This paper aims to provide a sensor for fast, sensitive and selective ethylene (C2H4) concentration measurements.
Abstract
Purpose
This paper aims to provide a sensor for fast, sensitive and selective ethylene (C2H4) concentration measurements.
Design/methodology/approach
The paper developed a sensor platform based on tunable laser absorption spectroscopy with a 3,266-nm interband cascade laser (ICL) as an optical source and a hollow waveguide (HWG) as a gas cell. The ICL wavelength was scanned across a C2H4 strong fundamental absorption band, and an interference-free C2H4 absorption line located at 3,060.76 cm−1 was selected. Wavelength modulation spectroscopy with the second harmonic detection (WMS-2f) technique was used to improve the sensitivity. Furthermore, the HWG gas cell can achieve a long optical path in a very small volume to improve the time response.
Findings
The results show excellent linearity of the measured 2f signal and the C2H4 concentration with a correlation coefficient of 0.9997. Also, the response time is as short as about 10 s. The Allan variance analysis indicates that the detection limit can achieve 53 ppb with an integration time of 24 s.
Practical implications
The ethylene sensor has many meaningful applications in environmental monitoring, industrial production, national security and the biomedicine field.
Originality/value
The paper provides a novel sensor architecture which can be a versatile sensor platform for fast and sensitive trace-gas detection in the mid-infrared region.
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