scholarly journals Real-Time Thermal Modulation of High Bandwidth MOX Gas Sensors for Mobile Robot Applications

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1180 ◽  
Author(s):  
Yuxin Xing ◽  
Timothy Vincent ◽  
Marina Cole ◽  
Julian Gardner
Keyword(s):  
Signal Processing ◽  
Mobile Robot ◽  
Real Time ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Low Cost ◽  
Signal Processing Technique ◽  
Chemical Reaction Kinetics ◽  
Sensor Module ◽  
High Bandwidth

A new signal processing technique has been developed for resistive metal oxide (MOX) gas sensors to enable high-bandwidth measurements and enhanced selectivity at PPM levels (<5 PPM VOCs). An embedded micro-heater is thermally pulsed from a temperature of 225 to 350 °C, which enables the chemical reaction kinetics of the sensing film to be extracted using a fast Fourier transform. Signal processing is performed in real-time using a low-cost microcontroller integrated into a sensor module. Three sensors, coated with SnO2, WO3 and NiO respectively, were operated and processed at the same time. This approach enables the removal of long-term baseline drift and is more resilient to changes in ambient temperature. It also greatly reduced the measurement time from ~10 s to 2 s or less. Bench-top experimental results are presented for 0 to 200 ppm of acetone, and 0 ppm to 500 ppm of ethanol. Our results demonstrate our sensor system can be used on a mobile robot for real-time gas sensing.

scholarly journals Thermal Modulation of a High-Bandwidth Gas Sensor Array in Real-Time for Application on a Mobile Robot

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 858 ◽  
Author(s):  
Timothy A. Vincent ◽  
Yuxin Xing ◽  
Marina Cole ◽  
Julian W. Gardner
Keyword(s):  
Signal Processing ◽  
Mobile Robot ◽  
Real Time ◽  
Low Cost ◽  
Processing Technique ◽  
Signal Processing Technique ◽  
Baseline Drift ◽  
Gas Sensor Array ◽  
Sensor Module ◽  
High Bandwidth

A new signal processing technique has been developed for resistive metal oxide (MOX) gas sensors to enable high-bandwidth measurements and enhanced selectivity at PPM levels (<50 PPM VOCs). An embedded micro-heater is thermally pulsed from 225 to 350 °C, which enables the chemical reactions in the sensor film (e.g., SnO2, WO3, NiO) to be extracted using a fast Fourier transform. Signal processing is performed in real-time using a low-cost microcontroller integrated into a sensor module. The approach enables the remove of baseline drift and is resilient to environmental temperature changes. Bench-top experimental results are presented for 50 to 200 ppm of ethanol and CO, which demonstrate our sensor system can be used within a mobile robot.

A two-stage method for real-time baseline drift compensation in gas sensors

2022 ◽  
Author(s):  
Chao Zhang ◽  
Wen Wang ◽  
Pan Yong ◽  
Lina Cheng ◽  
Shoupei Zhai ◽  
...  
Keyword(s):  
Real Time ◽  
Gas Sensors ◽  
Piecewise Linear ◽  
Low Cost ◽  
Piecewise Linear Approximation ◽  
Two Stage ◽  
Baseline Drift ◽  
Ambient Temperatures ◽  
Future Design ◽  
Drift Compensation

Abstract Baseline drift caused by slowly changing environment and other instability factors affects significantly the performance of gas sensors, resulting in reduced accuracy of gas classification and quantification of the electronic nose. In this work, a two-stage method is proposed for real-time sensor baseline drift compensation based on estimation theory and piecewise linear approximation. In the first stage, the linear information from the baseline before exposure is extracted for prediction. The second stage continuously predicts changing linear parameters during exposure by combining temperature change information and time series information, and then the baseline drift is compensated by subtracting the predicted baseline from the real sensor response. The proposed method is compared to three efficient algorithms and the experiments are conducted towards two simulated datasets and two surface acoustic wave sensor datasets. The experimental results prove the effectiveness of the proposed algorithm. Moreover, the proposed method can recover the true response signal under different ambient temperatures in real-time, which can guide the future design of low-power and low-cost rapid detection systems.

scholarly journals A Review of Carbon Nanotubes-Based Gas Sensors

2009 ◽  
Vol 2009 ◽  
pp. 1-24 ◽  
Author(s):  
Yun Wang ◽  
John T. W. Yeow
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Low Cost ◽  
High Surface ◽  
Hollow Structure ◽  
Volume Ratio ◽  
Fast Response ◽  
Sensing Technology ◽  
Structure Of Nanomaterials

Gas sensors have attracted intensive research interest due to the demand of sensitive, fast response, and stable sensors for industry, environmental monitoring, biomedicine, and so forth. The development of nanotechnology has created huge potential to build highly sensitive, low cost, portable sensors with low power consumption. The extremely high surface-to-volume ratio and hollow structure of nanomaterials is ideal for the adsorption of gas molecules. Particularly, the advent of carbon nanotubes (CNTs) has fuelled the inventions of gas sensors that exploit CNTs' unique geometry, morphology, and material properties. Upon exposure to certain gases, the changes in CNTs' properties can be detected by various methods. Therefore, CNTs-based gas sensors and their mechanisms have been widely studied recently. In this paper, a broad but yet in-depth survey of current CNTs-based gas sensing technology is presented. Both experimental works and theoretical simulations are reviewed. The design, fabrication, and the sensing mechanisms of the CNTs-based gas sensors are discussed. The challenges and perspectives of the research are also addressed in this review.

scholarly journals Understanding the Advanced Signal Processing Technique of Real-Time Adaptive Filters

2009 ◽  
Vol 25 (3) ◽  
pp. 145-160 ◽  
Author(s):  
Hilary Ahman ◽  
Lindsay Thompson ◽  
Amy Swarbrick ◽  
Julie Woodward
Keyword(s):  
Signal Processing ◽  
Real Time ◽  
Adaptive Filters ◽  
Processing Technique ◽  
Signal Processing Technique

Applications of Nanostructured Materials as Gas Sensors

2013 ◽  
Vol 201 ◽  
pp. 131-158 ◽  
Author(s):  
Ravi Chand Singh ◽  
Manmeet Pal Singh ◽  
Hardev Singh Virk
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Dominant Role ◽  
Low Cost ◽  
Critical Role ◽  
Health And Safety ◽  
Chemical Route ◽  
Metal Oxide Sensors

Gas detection instruments are increasingly needed for industrial health and safety, environmental monitoring, and process control. To meet this demand, considerable research into new sensors is underway, including efforts to enhance the performance of traditional devices, such as resistive metal oxide sensors, through nanoengineering. The resistance of semiconductors is affected by the gaseous ambient. The semiconducting metal oxides based gas sensors exploit this phenomenon. Physical chemistry of solid metal surfaces plays a dominant role in controlling the gas sensing characteristics. Metal oxide sensors have been utilized for several decades for low-cost detection of combustible and toxic gases. Recent advances in nanomaterials provide the opportunity to dramatically increase the response of these materials, as their performance is directly related to exposed surface volume. Proper control of grain size remains a key challenge for high sensor performance. Nanoparticles of SnO2have been synthesized through chemical route at 5, 25 and 50°C. The synthesized particles were sintered at 400, 600 and 800°C and their structural and morphological analysis was carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The reaction temperature is found to be playing a critical role in controlling nanostructure sizes as well as agglomeration. It has been observed that particle synthesized at 5 and 50°C are smaller and less agglomerated as compared to the particles prepared at 25°C. The studies revealed that particle size and agglomeration increases with increase in sintering temperature. Thick films gas sensors were fabricated using synthesized tin dioxide powder and sensing response of all the sensors to ethanol vapors was investigated at different temperatures and concentrations. The investigations revealed that sensing response of SnO2nanoparticles is size dependent and smaller particles display higher sensitivity. Table of Contents

Fabrication of a Carbon Nanotube Gas Sensor Microelectrodes and its Application for Ammonia Detection

2013 ◽  
Vol 431 ◽  
pp. 306-311
Author(s):  
Xiang Tao Ran ◽  
Zhi Wang ◽  
Li Yang
Keyword(s):  
Gas Sensors ◽  
High Performance ◽  
Gas Sensing ◽  
Structural Parameters ◽  
Low Cost ◽  
Manufacturing Method ◽  
Multi Walled Carbon Nanotubes ◽  
Ammonia Detection ◽  
Low Cost Manufacturing ◽  
Walled Carbon Nanotubes

With the increasing needs for high-performance gas sensors in industrial production, environmental monitoring and so on, the research on gas sensors is becoming more and more important. In this paper, the electric field intensity distribution simulation process of the interdigital microelectrodes (IMEs) is discussed in details to get the proper electrode structural parameters. The IMEs on the ITO surface with a minimum gap of about 4μm are achieved by lithography, which provides a reliable, low-cost manufacturing method. Sensitive components are made of the multi-walled carbon nanotubes modified materials. The gas-sensing property of the sensor is detected for ammonia. The experiment result shows that the performance of the nanomodified sensor is obviously improved.

ZnO-Based Gas Sensors Prepared by EPD and Hydrothermal Growth

2015 ◽  
Vol 654 ◽  
pp. 94-98 ◽  
Author(s):  
Roman Yatskiv ◽  
María Verde ◽  
Jan Grym
Keyword(s):  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
Zno Nanorods ◽  
Zno Films ◽  
Nanorod Arrays ◽  
Zno Nanorod Arrays ◽  
Current Voltage ◽  
Gas Sensing Properties

Arrays of vertically well aligned ZnO nanorods (NRs) were prepared on nanostructured ZnO films using a low temperature hydrothermal method. We propose the use of the low cost, environmentally friendly electrophoretic deposition technique (EPD) as seeding procedure, which allows the obtaining of homogeneous, well oriented nanostructured ZnO thin films. ZnO nanorod arrays were covered with graphite in order to prepare graphite/ZnO NRs junctions. These nanostructured junctions showed promising current-voltage rectifying characteristics and gas sensing properties at room temperature.

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