Design of a Low-Cost Emissions Sensor for Potential Use in Developing Communities

Turbidity stands as a crucial indicator for assessing water quality, and while turbidity sensors exist, their high cost prohibits their extensive use. In this paper, we introduce an innovative turbidity sensor, and it is the first low-cost turbidity sensor that is designed specifically for long-term stormwater in-field monitoring. Its low cost (USD 23.50) enables the implementation of high spatial resolution monitoring schemes. The sensor design is available under open hardware and open-source licences, and the 3D-printed sensor housing is free to modify based on different monitoring purposes and ambient conditions. The sensor was tested both in the laboratory and in the field. By testing the sensor in the lab with standard turbidity solutions, the proposed low-cost turbidity sensor demonstrated a strong linear correlation between a low-cost sensor and a commercial hand-held turbidimeter. In the field, the low-cost sensor measurements were statistically significantly correlated to a standard high-cost commercial turbidity sensor. Biofouling and drifting issues were also analysed after the sensors were deployed in the field for more than 6 months, showing that both biofouling and drift occur during monitoring. Nonetheless, in terms of maintenance requirements, the low-cost sensor exhibited similar needs compared to the GreenSpan sensor.

Air temperature variability in an urban environment is considered a vital element for understanding urban climate. The advancement in sensor design and data collection methods have made it possible to install and collect cost-effective urban climate data. The user-friendly applicability, sustainability, expandability and acceptance in the scientific community of the All-In-One (AIO) and Low-Cost (LC) sensors have ensured their popularity in an urban environment. The selection of air temperature sensors based on sensor accuracy, cost and various selection methods are being applied in scientific research. In this study we present a comparative assessment of air temperature sensors through a two-stage selection method. First, we selected the sensors (METSENS 600, ClimaVUE50, WXT536 from AIO and nMETOS180, Netatmo, SenseBox Home, iButton, HOBO-U23 from LC sensors) based on commercial availability, cost, accuracy, sensor weight, power supply and consumption, literature review and user-friendly data management system. Second, we tested the sensors applying climate chamber (CC) and in-situ testing. We found that HOBO-U23 had the lowest Mean Absolute Deviation as compared to the reference sensor in the daily cycle test, nMETOS180 in the extreme range test and in stable temperature testing during CC testing. The time series and statistical results for AIO sensors indicated that ClimaVUE50 had the lowest Mean Absolute Deviation (MAD), Root mean square deviation (RMSD), Mean Square Deviation (MSD), and highest coefficient of determination (R 2 ) values among the AIO sensors. Among the LC sensors, nMETOS180 showed lowest MAD, MSD, RMSD and highest R 2 values while Netatmo had the highest MAD, MSD, RMSD and lowest R 2 values. Deviations were mainly higher during the day and lower during the night due to radiation shield type variabilities. AIO sensors responded more slowly to changing temperatures due to thermal inertia and compactness as compared to most LC sensors. The study highlights clear deviations between AIO and LC sensors. Such deviations between sensors need in-depth investigation when comparing results between different sensors and different urban meteorological networks.

In this chapter, the development of a low-cost attitude sensor is introduced. In the previous chapters, the control system design method of several UAVs/MAVs with rotary wings was shown, and several kinds of controllers were designed. The most important controller is the attitude controller because if attitude control is not achieved, any other control such as velocity and position controls cannot be achieved. For achieving attitude control, it is necessary to measure the attitude of UAV/MAV. Hence, we require an attitude sensor. However, conventional attitude sensors are somewhat expensive and heavy, and they cannot be used for the attitude control of small UAVs and MAVs. Therefore, the design of an attitude estimation algorithm by using low-cost sensors, accelerometers, gyro sensors, and magnetic sensor is introduced. Finally, a low-cost attitude sensor has been developed and evaluated by comparing it with a conventional high-accuracy sensor.

The demand for energy is becoming increasingly important, and who says strong demands for energy says rising CO 2 emissions. Everyone agrees that a great part of the energy consumed by industry and households can be saved. The energy savings can take many forms. In addition to the necessity to build equipments more and more energy efficient, it is also necessary to get a clear view of how the energy is used. This obviously involves the implementation of an energy flow measuring system for long lasting optimization solutions. It is precisely in this context that the project CHIC (Low cost industry utilities monitoring systems for energy savings), funded by the French National Research Agency (ANR), emerged. The objective of this project is to develop and test low-cost non-intrusive sensors to monitor and analyze the energy consumption of major flows used in the manufacturing sector (electricity, gas, compressed air). With such sensors, it should be possible to tool up a factory, equipment by equipment, which is not feasible with intrusive sensors. The ultimate goal is the long term consumption monitoring and the detection of the consumption deviations rather than a precise measurement. The measurement accuracy is fixed to 5%. These developments are based on the recent approaches in system identification and parametric estimation. This project, concretely, involves the design of new low-cost sensors in the following areas: current sensors, voltage, power, and gas flow, relying on the international ISO 50001 standard for Energy Management Systems. The work presented in this chapter focuses on the modeling of the gas flow supplied to a boiler in order to implement a soft sensor. This implementation requires the estimation of a mathematical model that expresses the flow rate from the control signal of the solenoid valve and the gas pressure and temperature measurements. Two types of models are studied: LPV (Linear Parameter Varying) model with pressure and temperature as scheduling variables and a non-parametric model based on Gaussian processes.

This paper presents MEMS capacitive-based humidity sensors for monolithic integration with CMOS electronics. The fabrication process and design of the sensors are described. Performance is evaluated with theoretical analysis and finite-elements simulation. The design achieves a sensitivity greater than 0.225%/%RH and a response time faster than 1 s.

<p>The Permo-Triassic Sandstone aquifers of the Eden Valley, Cumbria UK, are a key water resource for public water supply in NW England as well as local agriculture and industries. Permo-Triassic Sandstone aquifers are characterised as having large storage capacities and moderate transmissivities, however, in the Eden Valley these characteristics vary greatly on a range of scales i.e. granulation seams (deformation bands) that are millimetres thick but have been shown to extend for hundreds of metres on analogous sandstones; silicified layers that are several metres thick and extending 10s to 100s of metres laterally; and lithological variation and faulting have been shown to juxtapose hydrogeological units with different hydraulic properties. Complex heterogeneous superficial deposits overlay 75% of the Permo-Triassic Sandstone aquifers and comprise glacial till, glacio-fluvial outwash deposits, river terrace deposits and alluvium. The lateral and vertical continuity of these superficial deposits is highly uncertain.</p><p> </p><p>The complex geological and superficial deposits in the Eden Valley impose a control on flow processes and impact sub-surface runoff. Specifically, lenses of high conductivity sands and gravels within low conductivity clay till deposits coupled with the presence of low conductivity strata at ground level suggests that indirect recharge is an important sub-surface runoff component. Therefore, the magnitude and location of recharge to the Permo-Triassic Sandstone aquifers is highly uncertain. Published recharge estimates rely on baseflow separation techniques and thus do not distinguish between indirect and direct recharge. This highlights the uncertainty regarding the sub-surface flow processes active in the Eden Valley.</p><p> </p><p>A methodology for characterizing the surface water – groundwater interaction spatially and temporally in an ungauged upland sub-catchment is presented.</p><p> </p><p>A non-invasive approach has been implemented to investigate the relationship between the surface water and groundwater systems in the Eden Valley. This involved the design and installation of low-cost ultrasonic sensors that measure stream stage. The sensors have been installed at key locations within sub-catchments that incorporate limestone pavements, geological contacts and along fault trends in the headwaters of the Eden Valley. Flow gauging has been conducted along the reach of these streams to investigate the spatial variation in discharge. Data from the low-cost sensors and flow gauging have been used to estimate the magnitude of volumetric water exchange between the surface water and groundwater systems, as well as characterise this relationship spatially and temporally.</p><p> </p><p>The thickness and composition of the superficial deposits along these stream reaches will be investigated via passive seismic survey. The superficial investigation and the volumetric water balance will be used to estimate indirect recharge in the upper Eden catchment. The results of which will be compared to localised recharge estimates calculated from groundwater level timeseries. This comparison will indicate the importance of indirect recharge within sub-surface runoff processes.</p><p> </p><p>This ongoing research is a vital step in quantifying the relationship between the surface water and groundwater systems in a complex upland catchment. A knowledge of the active sub-surface runoff processes highlighted are key for reliably assessing the long-term security of groundwater resources in the Eden Valley.</p>

A copolymer incorporating polyaniline was used as a sensing medium in the construction of a resistance based humidity sensor. Aniline monomer was polymerised in the presence of poly (butyl acrylate / vinyl acetate) and a copolymer containing polyaniline emeraldine salt was obtained. The sensing medium was then developed by redissolving 1-2 w/w% of the resulting polymer residue in dichloromethane to produce a processable polymer blend solution. Some of this polymer residue was also de-doped in a solution of ammonia, and then washed with distilled water until the waste water had a neutral pH. This residue was then redissolved at 1-2 w/w% in dichloromethane to produce a second processable polymer blend this time containing polyaniline emeraldine base. The final sensor design utilised 125μm polyester insulated platinum wire as conducting electrodes that were dip coated in the emeraldine salt copolymer solution and allowed to dry in a desiccator. The sensor was then dip-coated in a protective barrier layer of the emeraldine base copolymer to prevent over-oxidation and/or de-protonation of the emeraldine salt sensing medium under this coating. The sensors had an overall final thickness of less than 150μm and showed high sensitivity to humidity, low resistance, and good reversibility without hysteresis. Sensors were monitored for 2-probe resistance changes when in contact with water. Calibration curves for each sensor were produced to convert the resistance reading to mass uptake of water. Individual sensors were embedded within Aluminium 5083 / Araldite 2015 adhesive joints to monitor mass uptake of water when exposed to marine environments. Correlations between mass uptake of water and joint strength were made. There are various advantages of such a sensor design. Polymer based thin film humidity sensors have the advantage that the high processability of the material allows for simple fabrication of a range of geometries including smaller sensor designs. The ease of processing gives a low cost sensor, whilst the small size and good mechanical properties gives a robust sensor which has the flexibility to be able to be used in applications where dynamic stresses and strains are encountered. Such sensors may find uses in a number of areas including electronic textiles, food/ electronics packaging and corrosion detection.

Anthropogenic activities emit particulate matter (PM) and gaseous substances that are harmful. PM has adverse effects on different parts of the body. Atmospheric pollution is a global threat with an increasing social and economic costs. Poor air quality is a concern in African cities, but governments have been too slow to react, one of the reasons being the scarcity of data on different air pollutants. Instruments based on low-cost sensors and Internet of Things are being considered as solution to evaluate the concentration of different pollutants. Increasing number of manufacturers are proposing sensing devices with good accuracy. Low-cost sensors are an alternative to expensive high graded equipment. They are cheap and can be easily deployed. Here we present the IoT4AQ project. It is funded by the International Astronomical Union (IAU). The main objective is to organize training sessions for researchers and students on the design and implementation of low-cost sensors for air quality monitoring. The project will use astronomy instrumentation knowledge and skills. Participants will be trained in IoT techniques showing how to build low-cost sensors-based instruments and deploy them. The project starts on February 2023, will last for two years and trainers will be invited on various aspects of the trainings. Two hands-on trainings and two online seminars will be organized each year. The project will be implemented in Senegal and the first year will see the participation of local trainees and in the second phase it will open to participants from other African countries. Specific objectives are: (1) organize hands-on trainings and online seminars on IoT and air quality monitoring, (2) train researchers, teachers, and students on various aspects of air quality monitoring and (3) improve Physics education in Africa through low-cost sensors and IoT. Expected outcome are as follows: (1) train a minimum of 100 participants on IoT and air quality monitoring; (2) improve the experimental skills of participants; and (3) increase awareness of the threat that represents atmospheric pollution.

This paper reports on a low-cost turbidity sensor design for continuous on-line water quality monitoring applications. The measurement of turbidity by agricultural and environmental scientists is restricted by the current cost and functionality of available commercial instruments. Although there are a number of low-cost turbidity sensors exploited within domestic ‘white-goods’, such as dishwashers, the lack of sensitivity, and power-usage of these devices make them unsuitable for fresh-water quality monitoring purposes. The recent introduction of wireless protocols and hardware, associated with the ‘Internet-of-Things’ concept for machine-to-machine autonomous sensing and control, has enabled the large-scale networked intelligent water turbidity monitoring system that implements relatively low-cost sensors to be developed. The proposed sensor uses both transmitted light and orthogonal (90 degrees) scattered light detection principles, and is 2–3 orders of magnitude lower in cost compared to the existing commercial turbidity sensors. With an 850-nm infrared LED, and dual orthogonal photodetectors, the proposed design is capable of measuring turbidity within the range of 0–1000 Nephelometric Turbidity Unit (NTU) with improved accuracy and robustness as compared with the existing low cost turbidity sensors. The combination of orthogonal and transmitted light detection unit provides both 0–200 NTU high resolution and accuracy sensing and 0–1000 NTU lower resolution and accuracy sensing capability. Results from calibration experiment are presented, which proved that the proposed sensor design produced comparable turbidity readings as that of a commercial turbidity sensor.

<p>The study of intermittent and ephemeral streams is gaining more and more popularity, as the scientific community has acknowledged the fundamental impact of these streams on basic hydrological processes and important ecosystem services. Nevertheless, the understanding of the physical processes that drive this intermittency has been long hampered by the limited availability of empirical data. In fact, monitoring the event-based expansion and contraction of temporary streams through visual inspection is very demanding and time-consuming. To circumvent this limitation, several low-cost sensor designs for monitoring flow presence have been suggested in recent years. These sensor exploit either water temperature or electrical conductivity. However, these sensors are typically characterized by pointwise probes that water flows can easily dodge, particularly in streams with complex and unstable morphologies. Moreover, very few studies have been conducted that use networks of probes to monitor stream intermittency at the catchment-scale.</p><p>Here we present a field-application of an advanced version of the low-cost water presence sensor developed by Chapin et al., 2016. In particular, we tested a new probe design to continuously measure the electrical conductivity across a channel cross-section and, thus, infer the presence of water therein. More than 50 probes were installed to monitor the dynamics of several intermittent tributaries of a small headwater catchment in northern Italy during the summer and fall of 2019. This catchment encompasses a wide variety of stream types: mild and steep slopes, incised and flat geometries, rocky and vegetated riverbeds. The field application shows that the proposed probes are able to provide useful information about the temporary activation of ephemeral streams under a variety of environments and conditions. The reconstructed temporal dynamics of the stream network comply with the persistency maps previously derived based on visual inspection. This new sensor design enables the continuous-time monitoring of the activity of intermittent streams, providing easily interpretable data under diverse conditions. We conclude that low-cost water presence sensors provide a unique opportunity to expand the coverage of the available datasets about the dynamics of intermittent streams.</p>

In this paper we demonstrate the design of a low-cost optical current sensor. The sensor principle is the Faraday rotation of a light beam through a magneto-optical material, SF2, when a magnetic field is present. The prototype has a high sensitivity and a high linearity for currents ranging from 0 up to 800 A. The error of the optical fibre sensor is smaller than 1% for electric currents over 175 A.

This paper describes the design and development of a new sensor which is low cost to manufacture and install and is reliable in operation with sufficient accuracy, resolution and repeatability for use in newly developed systems for pipeline monitoring and leakage detection. To provide an appropriate signal, the concept of a "failure" sensor is introduced, in which the output is not necessarily proportional to the input, but is unmistakably affected when an unusual event occurs. The design of this failure sensor is based on the water opacity which can be indicative of an unusual event in a water distribution network. The laboratory work and field trials necessary to design and prove out this type of failure sensor are described here. It is concluded that a low-cost failure sensor of this type has good potential for use in a comprehensive water monitoring and management system based on Artificial Neural Networks (ANN).

Biometrics-based authentication of subjects is widely deployed in several real-life applications. Among various biometric characteristics, the finger-vein characteristic has demonstrated both reliable and highly accurate authentications for access control in secured applications. However, most of these systems are based on commercial sensors, where the image-level data are not available for academic research. In this paper, we present the design and development of a low-cost finger-vein sensor based on a single camera that can capture finger-vein images from dorsal and ventral parts of the finger with high quality. The system consists of multiple near-infrared (NIR) light sources to illuminate the finger from both sides (left and right) and top. The camera in the sensor is also coupled with the custom designed physical structure to facilitate high reflectance of the emitted light and distribute the light uniformly on the finger to capture good-quality dorsal and ventral finger-vein patterns. Extensive experiments are carried out on the data captured using the developed sensor and benchmarked the performance with eight different state-of-the-art (SOTA) algorithms. The results on a large-scale finger-vein dataset demonstrate the need for illumination from both sides (left and right) and from the top of the finger, to capture finger-vein images with high quality that improves the verification performance.

The increased use of Unmanned Ground Vehicles (UGVs) drives the need for new lightweight, low cost sensors. Microelectromechanical System (MEMS) based microcantilever sensors are a promising technology to meet this need, because they can be manufactured at low cost on a mass scale, and are easily integrated into a UGV platform for detection of explosives and other threat agents. While the technology is extremely sensitive, selectivity is a major challenge and the response modes are not well understood. This work summarizes advances in characterizing ultrasensitive microcantilever responses, sampling considerations, and sensor design and cantilever coating methodologies consistent with UGV point detector needs.

After a short description of the structure and operation of a pyroelectric sensor, the thermal conditions of the sensing element, the thermal-to-electrical conversion and the signal processing of pyroelectric thin film sensors will be represented. By means of the complex normalised current responsivity TR(jω, s) and figures of merit Mv, M1 and MD, an universal description of the sensor's internal operation is obtained. The influence of electrothermal coupling effects on the dielectric loss of the pyroelectric thin film is also discussed. Substantial requirements to the pyroelectric thin film and the sensor design are derived. A comparison of often used thin film ferroelectrics shows that the application of P(VDF/TrFE) in low cost sensors can be advantageous although the figures of merit are lower. Copolymer film can be easily deposited onto a silicon wafer in post-processing after read out circuit fabrication, for instance by spin coating of a copolymer solution. Furthermore, the very low thermal conductivity provides good thermal insulation between the pyroelectric film and readout circuitry. The chosen P(VDF/TrFE) with a molar content of 70 % VDF shows a spontaneous polarisation of 8 μCcm−2 and a pyroelectric coefficient of 3.5 nCcm−2K−1, a dielectric constant of 8 and a dielectric loss of about 0.018 at 25 °C. By a computer simulation, an optimum sensor design was achieved for single-element sensors and linear arrays. The central feature is a self-supporting carrier membrane of Si3N4 (about 150 nm) and SiO2 (500 nm), processed by bottom side etching of silicone wafers covered with a spin coated P(VDF/TrFE) thin film of about (1…2) μm in thickness. A radiation sensitive area (1×1) mm2 and (2×2) mm2 was choosen for the single-element sensor. In the linear array 128 pixels are arranged with a pitch of 100 μm, the pixel area is (90×100) μ2. A CCD read out circuit with gate modulation input structure is used as multiplexer. The specific detectivity D∗ (500 K, 10 Hz) of the single-element sensor is 3·108 cmHz½W−1. At a frequency of 40 Hz the linear array shows a NEP of 4.5 nW and a MTF of 0.32 at a spatial frequency of 3 lpmm−1.