Air Humidity Sensors Research Articles

Sensor Location Optimisation Design Based on IoT and Geostatistics in Greenhouse

Environmental parameters such as air temperature (T) and air relative humidity (RH) should be intensively monitored in a greenhouse in real time. In most cases, one set of sensors is installed in the centre of a greenhouse. However, as the microclimate of a greenhouse is always heterogeneous, the sensor installation location is crucial for practical cultivation. In this study, the T and RH monitoring performance of different sensors were compared. Two types of real-time environmental sensors (Air Temperature and Humidity sensor and Activity Monitoring sensor, referred as ATH and AM) were selected and calibrated by reliable non-real-time sensors (Honest Observer By Onset sensor, referred as HOBO). The results showed that T and RH were variable in a small greenhouse area (128 m2). ATH had better T and RH monitoring performance than AM using HOBO as a reference (R2 = 0.968 and 0.938 for T; 0.594 and 0.538 for RH, respectively, for ATH and AM). In terms of cost, it is more efficient to use more sets of AMs (15 sets were used in this case study) to establish an intensive monitoring system based on the Internet of Things (IoT) compared with that of ATH. Then, the optimal sensor installation location was decided using geostatistics. Based on a simulated monitoring data set, the optimal sensor installation location was determined to be 1.57 m away from the physical centre of the monitoring area. By combining IoT with geostatistics, this study offers a method for effective monitoring of environmental parameters in a practical greenhouse system with a three-step procedure.

A Mini-Survey and Feasibility Study of Deep-Learning-Based Human Activity Recognition from Slight Feature Signals Obtained Using Privacy-Aware Environmental Sensors

Numerous methods and applications have been proposed in human activity recognition (HAR). This paper presents a mini-survey of recent HAR studies and our originally developed benchmark datasets of two types using environmental sensors. For the first dataset, we specifically examine human pose estimation and slight motion recognition related to activities of daily living (ADL). Our proposed method employs OpenPose. It describes feature vectors without effects of objects or scene features, but with a convolutional neural network (CNN) with the VGG-16 backbone, which recognizes behavior patterns after classifying the obtained images into learning and verification subsets. The first dataset comprises time-series panoramic images obtained using a fisheye lens monocular camera with a wide field of view. We attempted to recognize five behavior patterns: eating, reading, operating a smartphone, operating a laptop computer, and sitting. Even when using panoramic images including distortions, results demonstrate the capability of recognizing properties and characteristics of slight motions and pose-based behavioral patterns. The second dataset was obtained using five environmental sensors: a thermopile sensor, a CO2 sensor, and air pressure, humidity, and temperature sensors. Our proposed sensor system obviates the need for constraint; it also preserves each subject’s privacy. Using a long short-term memory (LSTM) network combined with CNN, which is a deep-learning model dealing with time-series features, we recognized eight behavior patterns: eating, operating a laptop computer, operating a smartphone, playing a game, reading, exiting, taking a nap, and sitting. The recognition accuracy for the second dataset was lower than for the first dataset consisting of images, but we demonstrated recognition of behavior patterns from time-series of weak sensor signals. The recognition results for the first dataset, after accuracy evaluation, can be reused for automatically annotated labels applied to the second dataset. Our proposed method actualizes semi-automatic annotation, false recognized category detection, and sensor calibration. Feasibility study results show the new possibility of HAR used for ADL based on unique sensors of two types.

Rancang Bangun Sistem Monitoring Suhu dan Kelembaban Udara Pada Ruang Server Berbasis Wireless Sensor Network

A server has a pivotal role that needs certain attention when the server starts up. The server has data such as important documents stored on the server computer database. One of the factors that obstacle the server performance is a room that has a high temperature or humidity. In addition, the administrator is not able to check the state of the server room frequently. The purpose of this research is to design a temperature and humidity monitoring system in a server room based wireless sensor network. The method used is wireless sensor network. This method pursues the network administrators to monitor the conditions of the temperature and humidity in the server room. The research results show that the error generated by the sensor is relatively small. The average error generated by the temperature sensor is 0.12985% and the error generated by the air humidity sensor is 0.611538%. The collected temperature and humidity data can be displayed and stored on the web application and mobile view

Highly Enhanced Triboelectric Performance from Increased Dielectric Constant Induced by Ionic and Interfacial Polarization for Chitosan Based Multi‐Modal Sensing System

AbstractThe coexistence of increasingly severe environmental concerns and bio‐signal sensing systems drives the development of environmental affinity and energy harvesting materials. Chitosan is a richly sourced biodegradable material derived from crustaceans, which provides a new option for environmentally, wearable triboelectric nanogenerator (TENG). In this paper, the triboelectric performance of chitosan blends are proposed to enhance the dielectric constant by optimizing the ionic polarization and interface polarization for the first time, which fills in the blank of enhancing the output of chitosan triboelectric by systematically engineering in ionic/molecular and pH effect. Triboelectric output enhanced chitosan film in TENG shows an output voltage 3 times (18 V) higher than that of the initial film and 25 times (200 V) higher after corona charge injection. The chitosan film for wearable devices not only can be used as a unit of a triboelectric device to measure human motion signal, but also can be used as a piezoresistive sensor (ΔR/R0: 0 to 1.5) and an air humidity sensor (relative humidity: 20% to 90%) after mixing carbon black. The study provides a stimulating example that triboelectric nano generator/piezoresistive sensor is made from chitosan and used in the multi‐modal sensing system.

Wireless Sensing Module for IoT Aquaponics Database Construction

The interest in aquaponics has been increasing in the last years since it may become one of the solutions for food scarcity around the world and the need for green and sustainable technologies in the food industry. Nevertheless, an aquaponics process is quite complex and the need for further studies about the parameter’s relationships that establish a base for future technological implementations is needed. This research project presents the development of a framework that involves the creation of a wireless sensing module that uses a pH, electroconductivity, water temperature, light resistor, air humidity, and air temperature sensor and the connection to a database capable of storing and linking the information to a quality assessment tool that can be used for future smart applications towards the feasibility of aquaponics at commercial scale.

Merenje visine leta kvadkoptera pomoću low-cost barometarskog, infracrvenog, ultrazvučnog i lidar senzora

The goal of this research is to assess the different low-cost sensors for flight altitude measuring of a multirotor UAV at low altitude flight. For optimizing the sensor performances and accuracy, data filtering and other methods were applied. The flight altitude data were collected and stored for later analysis with reference to the true altitude. The correlation coefficient and the mean squared error were calculated in order to assess the sensors' performance. On the basis of the results of the study, it was possible to determine the choice of the adequate sensor for this specific use. The study showed that the best characteristics for this experiment conditions had the Garmin LIDAR-Lite V3HP sensor and the Bosch Sensortech BME280 that combined air humidity, atmospheric pressure, and air temperature sensor.

Оптоэлектронный датчик относительной влажности воздуха

This paper discusses the main characteristics of atmospheric air, the selected closed object on which the relative humidity depends to a certain extent, as well as a laboratory installation for studying the principle of constructing an optoelectronic sensor for measuring relative humidity. A description and diagram of the air humidity sensor, a block diagram of the installation for continuous monitoring of air humidity in the controlled object, a device for calibrating humidity sensors, and an algorithm for calibrating humidity sensors are given.

Yield Evaluation of Brassica rapa, Lactuca sativa, and Brassica integrifolia Using Image Processing in an IoT-Based Aquaponics with Temperature-Controlled Greenhouse

The paper introduced the development of a self-sustainable smart aquaponics system in a temperature-controlled greenhouse with a monitoring and automatic correction system using an Android device through the Internet of Things (IoT) and plant growth monitoring system through image processing using Raspberry Pi. The system involves the acquiring of real-time data detected by the light intensity sensor, and air temperature and humidity sensor. It also includes the monitoring of the pH level and temperature of the recirculating water of the system. If the acquired data is not within the threshold range, the correcting devices, namely grow lights, exhaust and inlet fans, evaporative cooler, aerator, and peristaltic buffer device were automatically triggered by the system to correct and achieve its normal status. The internet remote access includes the effective wireless transmission and reception of data reports between the system and an Android unit with the Android application in real-time. The study focused on the evaluation of two experimental set-ups comparing the plant growth between conventional soil-based farming and the smart aquaponics system using image processing. After data gathering, results showed that the smart aquaponics set-up successfully produced a yield better than the conventional farming set-up.

Performance Evaluation of a Smart Mobile Air Temperature and Humidity Sensor for Characterizing Intracity Thermal Environment

AbstractHeat stress caused by high air temperature and high humidity is a serious health concern for urban residents. Mobile measurement of these two parameters can complement weather station observations because of its ability to capture data at fine spatial scales and in places where people live and work. In this paper, we describe a smart temperature and humidity sensor (Smart-T) for use on bicycles to characterize intracity variations in human thermal conditions. The sensor has several key characteristics of internet of things (IoT) technology, including lightweight, low cost, low power consumption, ability to communicate and geolocate the data (via the cyclist’s smartphone), and the potential to be deployed in large quantities. The sensor has a reproducibility of 0.03°–0.05°C for temperature and of 0.18%–0.33% for relative humidity (one standard deviation of variation among multiple units). The time constant with a complete radiation shelter and moving at a normal cycling speed is 9.7 and 18.5 s for temperature and humidity, respectively, corresponding to a spatial resolution of 40 and 70 m. Measurements were made with the sensor on street transects in Nanjing, China. Results show that increasing vegetation fraction causes reduction in both air temperature and absolute humidity and that increasing impervious surface fraction has the opposite effect.

Identification of the Transient Response of a Capacitive Relative Humidity Sensor

This paper presents the results of identifying the transient response of a relative air humidity sensor. It is shown that the capacitive relative humidity sensor is an integrated microprocessor system that performs joint processing of the readings of the absolute humidity sensor and the temperature sensor. A mathematical model of the relative humidity measurement process is proposed. The transient responses of the absolute humidity sensing element and the temperature sensor are specified under the assumption that they correspond to first-order aperiodic factors. Based on the relationships of thermodynamics, Arden Buck equation, and given transient functions, analytical dependencies are obtained to identify the parameters of the transient response of the capacitive relative humidity sensor. The results of several field experiments are processed and analyzed in accordance with the proposed mathematical model. The effect of anomalous sensor readings is revealed and consists in the fact that with simultaneous stepwise changes in humidity and temperature, the sensor records a change in relative humidity with the opposite sign. It has been established that the cause of the anomalous results of relative humidity measurements is the presence of a large difference between the response time constant of the absolute humidity sensing element and that of the temperature sensor. Measures are proposed to prevent anomalous results of relative humidity measurements.

Fuzzy Tsukamoto Implementation on Internet of Things to Control Flooding

A Flooding is a disaster that often occurs in the Semarang area, especially on Jl. Raya Kaligawe. Flooding can occur due to the ineffectiveness of the pump work in a water impregnation pool. The impact of the floods is detrimental to students because with the flooding it can interfere with teaching and learning activities and studying student activities when on campus. At Sultan Agung Islamic University, Semarang has a water impregnation pool that is still manually controlled. By using Fuzzy Tsukamoto as artificial intelligence on Internet of Things technology, we can carry out intelligent control systems in water absorption pool pumps in realtime, so as to prevent and reduce human error that causes flooding. In principle, the Internet of Things works using a microcontroller, one of the microcontrollers that can be used, namely Wemos D1 mini. Wemos D1 mini is connected with an ultrasonic sensor to measure water level in a water infiltration pond, air temperature and air humidity sensor to detect rain.

Automatic Control System for Swallow's Nest Cultivation Using the Internet of Things

In swallow nest cultivation, swallow breeders still have difficulty in tropical climates, one of which is maintaining the temperature and humidity in the swallow nest room to be stable and to know the value of swallow population. When the temperature is hot, the swallow room will become dry which impacts on the nest is damaged and the swallow is not comfortable living there. Therefore, a system that can be easily managed by swallow farmers is made so it can help reduce hot temperature and lack of humidity in the swallow nest room by using a sprayer that works automatically. In this system, there are temperature and humidity detection module which functions to detect the temperature valueand humidity when the room is hot / dry, the detected value will be processed by the microcontroller so that it gives an active sprayer command if the room temperature is hot, while the swallow detection module that uses infrared sends the movement value if there is a moving object. The value of the system will be sent to a cloud database which will be conveyed via the farmer wallet smartphone application. The accuracy level of the infrared detector sensor module and the air humidity sensor is very good, so that it can control the temperature conditions in the swallow room which is 27 degrees C and a stable humidity at a value of 80%. The stability of temperature and humidity produces swallow nests which have high selling value.

Experimental Comparison of Construction Material Vapor Permeability in Case of Horizontal or Vertical Sample Position

The paper proposes a device for vapor permeability coefficient determination in case of vertical sample position. The device is a L-type section capacity with a window in upper part of long side of the capacity. A test sample of construction material is positioned vertically and sealed in the window. The capacity has built-in relative air humidity sensors distributed along capacity height. These sensors allow measuring height-average relative air humidity. Experimental vapor permeability coefficient values, obtained by means of the proposed device and by means of well-known wet cup method, have been compared. Rock wool has been used as a test material. As a result, wet cup method has been confirmed for vapor permeability coefficient determination for vertical enclosing structures.

Design and implementation of a low cost photovoltaic soil moisture monitoring station for irrigation scheduling with different frequency domain analysis probe structures

Frequency Domain Analysis (FDA), as an approach, has been developed for the measurement of soil dielectric constants. As it stands, the standard dielectric of dry soil is much less than the dielectric of soil exposed to water, and the volume of water present significantly affects the propagation of electromagnetic waves. With this in mind, this paper proposes a plan for the design and implementation of two distinct isolated probe structures for the measurement of water contents within the soil at different levels. Accordingly, Probe A is used to determine the water level present in soil at four different depths. Probe A does this by utilizing pairs of parabolic copper sections fixed horizontally and isolated over the outer surface of an access tube. Probe B, on the other hand, makes use of two steel rings buried vertically inside of an access tube, and is used to determine the water contents of soil on two levels. To do so, a fixed frequency square-wave is transmitted to measure the soil capacitance in which the probe sensors are connected to an Arduino microcontroller which also included air humidity, air temperature, and soil temperature sensors. During the experimental assessment of both probes, the results are loaded onto an SD memory card and are then compared with the results of other commercial sensors installed in the same irrigated plot. The soil moisture monitoring station used is powered by a photovoltaic (PV) module of 10 W 12 V and a storage battery of 12 Ah. The experimental monitoring station used to assess the efficiency of both probe designs was set up in a Mediterranean semiarid zone in the Southeast of Spain.

Wireless Internet of Things-Based Air Quality Device for Smart Pollution Monitoring

Living in a healthy environment is a need for every human being whether indoor or outdoor. However, pollutions occur everywhere and most people are merely mindful of the importance of having clean outdoor air to breathe and are not concerned about the indoor air quality. Indoor air quality refers to the quality within the building, and relates to the health and comfort of the building occupants. Dangerous particles exist in the outside air, pollute the indoor environment and produce harmful conditions as the polluted air travels into the house or building through windows or doors. Therefore, a wireless Internet of Things-based air quality device is developed to monitor the air quality in the indoor environment. The proposed system integrates a low-cost air quality sensor, temperature and humidity sensors, a single-board computer (Raspberry Pi 2 microprocessor) and cloud storage. The system provides realtime air quality reading, transfers the data through a wireless network to the Internet and displays the data in dedicated webpage. Furthermore, it stores records in cloud storage and sends e-mail notification message to the user when unhealthy condition is met. The study has a significant impact on promoting affordable and portable smart pollution monitoring system as the development of the device utilizing low-cost and off-the-shelf components.

Design of Wireless Sensor Network Bidirectional Nodes for Intelligent Monitoring System of Micro-irrigation in Litchi Orchards

Wireless sensor network (WSN) bidirectional nodes, including the sensing node and the solenoid valve control node, were developed for information collection and micro-irrigation monitoring system in a litchi orchard, aimed at improving the problem of wireless communication barriers and the micro-irrigation management efficiency. The sensing node was composed of an MCU8051, a CC2530 RF chip for communication, a RFX2401for amplification. This node is supposed to collect data from a DHT22 air temperature and humidity sensor, a GY-30 light intensity sensor and a TDR-3 soil moisture sensor. The control node includes an MCU8051, a CC2530 RF chip for communication, and peripheral drive circuits for adapting the bi-stable pulse solenoid valve. The application software and backstage management software were written with these two nodes as the hardware platform, based on ZStack agreement. The maximum effective bidirectional communication distance of the designed nodes reached 1205m in unoccupied regions and 122m in litchi orchards. Within a 30 min working cycle, it could be estimated that two 3.7 V battery with a rated capacity of 3000 mA•h can power the sensing node for time up to 500d. Test results in litchi orchards show that the average packet loss rate is 0.75%. The system was processing smoothly with the above nodes for information acquisition and controlling micro-irrigation in litchi orchards.

Simultaneous multicopter-based air sampling and sensing of meteorological variables

Abstract. The state and composition of the lowest part of the planetary boundary layer (PBL), i.e., the atmospheric surface layer (SL), reflects the interactions of external forcing, land surface, vegetation, human influence and the atmosphere. Vertical profiles of atmospheric variables in the SL at high spatial (meters) and temporal (1 Hz and better) resolution increase our understanding of these interactions but are still challenging to measure appropriately. Traditional ground-based observations include towers that often cover only a few measurement heights at a fixed location. At the same time, most remote sensing techniques and aircraft measurements have limitations to achieve sufficient detail close to the ground (up to 50 m). Vertical and horizontal transects of the PBL can be complemented by unmanned aerial vehicles (UAV). Our aim in this case study is to assess the use of a multicopter-type UAV for the spatial sampling of air and simultaneously the sensing of meteorological variables for the study of the surface exchange processes. To this end, a UAV was equipped with onboard air temperature and humidity sensors, while wind conditions were determined from the UAV's flight control sensors. Further, the UAV was used to systematically change the location of a sample inlet connected to a sample tube, allowing the observation of methane abundance using a ground-based analyzer. Vertical methane gradients of about 0.3 ppm were found during stable atmospheric conditions. Our results showed that both methane and meteorological conditions were in agreement with other observations at the site during the ScaleX-2015 campaign. The multicopter-type UAV was capable of simultaneous in situ sensing of meteorological state variables and sampling of air up to 50 m above the surface, which extended the vertical profile height of existing tower-based infrastructure by a factor of 5.

物联网智能浇灌控制系统

传统果园种植低效且工作繁重，物联网技术+传统果园种植的模式有利于提高果园管理效率。本文采用STM32系类单片机、2.4 G无线模块，结合Unity3D引擎移动开发平台，设计和开发了一种物联网+Unity3D可交互智能化虚拟现实果园种植远程监控控制系统。该系统由底层部分和顶层部分组成，底层部分设计使用土壤湿度传感器和空气温湿度传感器检测果园土壤温度和外部环境温度和湿度信息，控制器根据不同果树土壤湿度设定值，调节电磁阀，控制浇水量。顶层部分设计建立三维虚拟场景，实现场景漫游、实时监视、信息显示功能。底层部分与顶层部分建立协议，通过查询果树养殖专业信息设定智能浇灌，同时也建立远程手动控制浇灌，方便管理人员随时查看数据和远程控制浇灌，降低果园养护难度。 Traditional orchard cultivation is inefficient and heavy work, and the Internet of Things technol-ogy + traditional orchard cultivation mode is conducive to improving the efficiency of the orchard management. In this paper, with STM32 series of single-chip microcomputer, 2.4 G wireless module, and Unity3D engine mobile development platform, we design and develop an orchard planting remote monitoring and control system of Internet of Things + Unity3D interactive intelligent virtual reality. The system consists of the bottom part and the top part of the composition. The bottom part of the design uses soil moisture sensors and air temperature and humidity sensors to detect the soil temperature and outdoor environment temperature and humidity information. According to different fruit soil moisture settings, the controller adjusts the solenoid valve and controls the amount of irrigation. The top part of the design establishes three-dimensional virtual scene to achieve roaming, real-time monitoring, and information display. The bottom part establishes protocols with the top part, then we can investigate fruit tree farming professional information to set the intelligent watering, and establish remote manual control watering, which facilitate the management staff at any time to view the data and remotely control watering, thus reducing the difficulty of orchards maintenance.

The course, stratification and possibility of simulating relative air humidity in winter wheat stand

AbstractThe aim of this study was: (i) long-term (2010, 2011 and 2013) evaluation of the relative air humidity in the winter wheat canopy, (ii) finding of relationships between relative air humidity in canopy and computed or measured meteorological values (precipitation totals, evapotranspiration, moisture balance, specific air humidity, volume soil moisture, % of available soil water content, value of soil water potential), (iii) testing of simulation of daily relative air humidity, based on selected meteorological values and potential evapotranspiration (FAO Penman-Monteith method) and actual evapotranspiration, (iv) testing of simulation of relative air humidity hourly values in the wheat canopy, (v) evaluation of dependence between relative air humidity and leaf wetness. The measurement was performed at the experimental field station of Mendel University in Žabčice (South Moravia, the Czech Republic). Data recording for wheat canopy was conducted by means of a meteostation equipped with digital air humidity and air temperature sensors positioned in the ground, effective height of the stand and in 2 m above the ground. The main vegetation period of wheat was divided into three stages to evaluate differences in various growing phases of wheat. The data from nearby standard climatological stations and from agrometeorological station in Žabčice were used for establishment of relationships between relative air humidity in winter wheat canopy and surrounding environment by correlation and regression analysis. Relative air humidity above 90% occurred substantially longer on the ground and at the effective height of the stand in comparison with the height of 2 m. By means of regression analysis we determined that the limit of 90% was reached in the canopy when at the climatological station it was just 60 to 90% for ground level and 70 to 90% for effective height, especially during the night. Slight dependence between measured or computed meteorological variables and relative air humidity in winter wheat canopy was found (r= 0.23 − 0.56 for precipitation totals,r= 0.27 − 0.57 for % of available soil water capacity, etc.). The simulation of hourly values of relative air humidity in wheat canopy is partially possible just when using the data of relative air humidity from the relevant standard climatological station.

Droplets spectrum of air-assisted boom sprayers under different environmental and operational conditions

ABSTRACT During pesticide spraying, the psychrometric conditions of the air may cause evaporation of the droplets along their trajectory from the nozzle to the target. Thus, this study aimed to evaluate the effect of air psychrometric conditions and operating pressure on the droplet spectrum of air-assisted boom sprayers. The test was performed using a prototype equipped with an axial fan, a flow homogenizer, temperature and relative air humidity sensors, a spray nozzle and a gas-heating system to warm up the airflow. With the assembled system and the aid of a particle analyser, the JSF 11002 spray nozzle was evaluated with respect to droplet spectrum in four air psychrometric conditions (7, 14, 21 and 28 hPa) and at four operating pressures (200, 300, 400 and 500 kPa). At the end, evaporation losses were observed during the sprayings. For a given operating pressure and for each increment of 1 hPa in vapor pressure deficit, there was a diameter reduction of approximately 0.0759, 0.518 and 1.514 μm for the parameters DV0.1, DV0.5 and DV0.9, respectively. The diameter of the droplets decreased as the operating pressure increased.