1.1 Background of Study
Nowadays, innovations in information communication technology have been increasing the convergence among the industries [1, 2]. These convergence and integration of IT with agricultural technology are expected to be an area that could increase the added value and productivity of agriculture by applying the ubiquitous technology to the agricultural sector which is a primary industry [3, 4]. To successfully construct such as agricultural environment, the development of essential ubiquitous technology need to be optimized for agriculture such as sensor hardware, middleware platforms, routing protocols and application services for agricultural environments. For the examples, the convergence of ubiquitous technology with agriculture, which is a primary industry, on a trial basis exist, such as the use of sensor nodes in vine culture sites and applications of ubiquitous technology in livestock farming sites, and the technology has gradually begun to appear in other small areas like the increase of production and the improvement of quality at various agricultural areas [5, 7].
The agricultural environment monitoring system provides environmental monitoring services, facility controlling services and the maintaining of the crop growing environment in an optimal status. This system also help to improve the convenience and productivity of users. On the other hand, the existing agricultural monitoring systems are mostly
applied and utilized in closed agricultural environments such as greenhouses, cattle sheds and others but it is difficult to apply agricultural monitoring systems in outdoors locations such as at the paddies' field, fields and orchards because of a lack of IT infrastructure and equipment. Moreover, when users want to verify the information in existing monitoring systems, the user must manually check the status through installed sensors or terminals installed in the agriculture facilities.
For solving these problems, we need to develop an agricultural environment monitoring system that can monitor environmental information such as temperature and humidity in a remote location and the system can be used in agricultural environments which lack infrastructure and had limited equipment. Weather Monitoring System can be differentiating into wired or wireless system. In case of wired communication, the connectivity will be more stable and faster. In case of wireless communication, the connectivity will be more convenient and user-friendly and weather monitoring would not require physical presence of the person at the location . Wireless communication also is the transfer of information or data over a distance without the use of wires from the transmitter to the receiver. The distance of transferring data can be short or long.
The wireless weather monitoring system can be implement on the platforms of the Unmanned Aerial Vehicle (UAV). The unmanned aerial vehicle (UAV) is commonly referred to as a remotely piloted aircraft, which can either be controlled from a remote location, or it can fly completely autonomously according to a pre-planned flight path or real-time navigation system. Ever since its invention, the UAV is commonly used for military purposes. Until now, a wide variety of civilian applications have emerged, indicating bright market prospects for the commercial UAVs in the future. The UAVs are commonly preferred for missions which are too “dull, dirty, or dangerous” whether in military or commercial such as in modern warfare, forest fire fighting and monitoring the crops at the farms . However, apart from its obvious advantages in risky and hazardous
missions, the UAVs also have a lot of advantages such as higher reliability, lower cost, smaller dimensions, and better flexibility. The UAVs can be tasked for various applications with the different payloads. For agriculture applications, the use of multispectral remote sensing data has gained increasing interest from researchers all over the world. The remote sensing approaches that have been developed for management of water, nutrients, and pests in agricultural crop.
On the other hand, this propose project more focused on the developments of prototype agriculture remote sensing system based on Unmanned Aerial Vehicle (UAV). The developed system employed cost effective Raspberry Pi Micro-computer and the integration of monitoring sensors namely temperature and relative humidity sensors. An UAV technology is also applied to the assist the monitoring of the system as an effective way to provide real time communication and monitoring life cycles. The proposed system will install these sensors on the UAV and perform the control function by means of Raspberry Pi. The analogue outputs of the sensors will be converted to digital signals and further processed by a Raspberry Pi, acting as data logger. Using easily-available components and simple circuitry, the system should be beneficial in providing a portable and low-cost remote weather monitoring system. This proposed system is low-cost and highly scalable both in terms of the type of sensors and the number of sensor nodes, which makes it well suited for a wide variety of applications related to environmental monitoring. A UAV drone will act as the mobile mechanism to monitoring environment temperature and relative humidity. Based on the real time monitoring system information, several automation mechanisms are embedded in the system to effectively resolve and minimize the impact of unusual environmental effect. The proposed prototype development can be extended to large scale agriculture farming as well as to the field of conservation ecology.
1.2 Problem Statement
This project can be the biggest utility of the wired-wireless weather monitoring in many areas ranging from agricultural and horticulture growth hence development to industrial development. The weather conditions of a field can be monitored from a distant place by farmers and won't require them to be physically present there in order to know the climatic behavior at the location by using wireless communication. It will be of great for farmers to monitor their farm remotely from home instead of visit their farm regularly. Furthermore, the need for a robust, economical and extendable system for measuring temperature and humidity, in small-scale commercial horticulture, where system cost is an issue. For this reason, this paper aims to build a low-cost, yet reliable, weather monitoring system capable of acquiring and recording data remotely using UAV and Raspberry Pi.
1.3 Project Objectives
1. To develop a prototype of temperature and humidity monitoring system using Raspberry Pi for the application of agriculture remote sensing.
2. To consolidate Raspberry Pi monitoring system on the Unmanned Aerial Vehicle (UAV) drone to allow remote monitoring function.
3. To perform functional test and In-situ onsite Pilot testing based on the developed prototype model.
1.4 Project Scope
1. Project will only focus on the prototype development of remote monitoring system using Raspberry Pi.
2. The monitoring features should consist of temperature and relative humidity sensors that will attach on the platform of UAV.
3. The functional of the complete prototype system are solely depending on the speed and capacity of UAV drone with respect to the limitation of weight and altitude that can be supported.
2.1 Importance of Agricultural
A simple definition state that agriculture is the cultivation of animals, plants and fungi for food, fiber, biofuel, medicinal and other products that used to sustain and enhance human life. Agriculture was the key for the development in the rise of sedentary human civilization, and farming of domesticated species created food surpluses that nurtured the development of human civilization. The study of agriculture is known as agricultural science. The history of agriculture dates back thousands of years, and its development has been affected by greatly different climates, cultures, and technologies. In the civilized, industrial agriculture based on large-scale monoculture farming has become the dominant agricultural methodology.
Development agricultural economists in particular have long focused on how agriculture can best contribute to overall growth and modernisation. Most of the early analysis highlighted the agriculture because of its abundance of resources and the ability to transfer surpluses to the more important industrial sector [41, 42, 45, 48, 53, 54]. Agriculture's main role in the transformation of the economy development was seen as subordinate to the central strategy of increasing the pace of industrialization. This conventional approach to the roles of agriculture in development concentrated on agriculture's important market-mediated linkages, providing labour for the industrial workforce, producing food for
expanding human populations with higher incomes, supplying savings for investment in industry, enlarging markets for industrial output, providing export earnings to pay for imported capital goods; and producing primary materials for agro-processing industries [40, 43, 52]. There are strong reasons for why these early approaches more focused on agriculture's economic roles as a one-way path involving the flow of resources towards the industrial sector and urban centres. When the national incomes rise, the demand for food increases more slowly than other goods and services. New technologies for agriculture lead to expanding food supplies per hectare or per worker. The increasingly modernising economies use more intermediate inputs purchased from other sectors. This decline in agriculture's share is partly the result of post-farm gate activities, such as taking produce to market, that become commercialized and are taken over by specialists in the service sector, and partly. This is because due to the producers substitute chemicals and machines for labour. Farmers' increasing use of purchased intermediate inputs and off-farm services adds to the relative decline of the producing agriculture sector in terms of overall employment [50, 55].
A number of development economists attempted to point out that, while agriculture's share fell relative to industry and services, it nevertheless grew in absolute terms, evolving increasingly complex linkages to non-agriculture sectors. Some of the researcher highlighted the interdependence between agricultural and industrial development and the potential for agriculture to stimulate industrialization [39, 44, 46, 47, 49, 51].
2.2 Plant Requirements and Environment Needs
There are two major criteria which are temperature and relative humidity significantly importance for the environment conditions at the farm. As an example, the weather monitoring may be based on an assessment of crop needs at the farm, temperature, the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water and solar light availability. Optimization has been a consistent goal of climate control for commercial plant production. Optimization may involve in determining the better way through a day or through an overall crop cycle to increase the agriculture production.
Plants grow well only within a limited range of temperature. When the temperature are too high or too low, it will result in abnormal development and reduced production. The vegetables for warm-season and most flowers grow best between 60° and 75° or 80° F. Cool-season vegetables such as lettuce and spinach should be grown between 50° and 70° F. High temperatures are unfavorable for growth of many landscape plants due to their rate of photosynthesis begins to decrease rapidly after a critical high temperature is reached . It is too difficult to define one critical high temperature for plants because it varies with species, but the temperatures in the 90° to 100° F range undoubtedly slow for the important of food-making process. Unfortunately for trees and shrubs, respiration is not quite sensitive compare to the high temperatures, and continues day and night, further depleting food reserves. Finally, high temperatures may simply cause injurious water loss when transpiration which is the process by which leaves release water vapor to the atmosphere and exceeds moisture absorption by the roots. High temperatures also cause injury to the roots. Optimum temperatures for root growth range from 60° to 80° F, but when landscape plants are grown in above-ground containers or in urban environments, their roots may experience unusually high temperatures. Temperatures 95° F and higher can be lethal to the roots of many plants . Low temperatures also present their own problems for woody landscape plants. Most of the trees and shrubs tolerate a certain amount of freezing in stems, branches, trunks, and in some cases leaves, after undergoing a seasonal change in metabolism known as acclimation. Cold hardy plants that have entered this quiescent or dormant state are generally capable of tolerating severe cold. But low temperature injury may occur when the temperatures fall below a plant's maximum cold hardiness limit, even after normal acclimation has occurred, premature freezing occurs before a plant has acclimated in the fall, unusually late freezes occur in the spring after a plant has deacclimated and when there are dramatic swings in temperature during the winter that cause a plant to deacclimate before the threat of severe freezing is over. In any discussion of cold hardiness it is important to remember that plants are made up of many different organs and there can be significant differences in hardiness among them. Roots, for example, are much less cold hardy than stems and branches and temperatures below 24° F can be lethal to roots. But there also can be differences in hardiness among above-ground parts of the plant . For example, flower buds are usually much less cold hardy than vegetative buds. Therefore, a plant's ability to tolerate both high and low temperatures must be taken into account when considering it for a given landscape situation.
2.2.2 Relative Humidity
When receiving the correct amount of water and light, moisture in the air in the form of water vapor greatly affects plant health. Water vapor means the gaseous, invisible state of water in the air known as humidity. Humidity is dampness, especially of the air. For the relative humidity; Humidity is a measure of the amount of water vapour contained within the air which is usually expressed as percentage humidity . Humidity is one of the important environmental element that must be controlled for healthy plants, and connoisseur grade meds. Humidity can controls the rate of transpiration and how the nutrients are received by the plant. Same as with humans, if the humidity gets too low, our skin will become dry and flaky. We transpire by sweating more fluids out at lower humidity levels. The humidity level is like a pressure cap on the plant, keeping the moisture in the plant, allowing it to have proper transpiration rates of the fluids. Ideal humidity levels in a grow room range between 50% to 70% in vegetative growth, and 50% to 60% for flowering plants. When humidity levels drop too low, the plants transpire at a rate much quicker than that of nutrient uptake. The nutrients or minerals do not transpire through the plant but only the water does. So this leaves behind a concentrated level of nutrients in the plant that will actually cause a nutrient burn. Most people do not realize in situations like these that the humidity could be responsible; usually thinking that it is too many nutrients in the reservoir. Just as a lack of CO2 can cause a plant to go dormant, low humidity can cause a plant to have nutrient problems, resulting from the transpiration rate being much too high in low humidity level environments. Conversely, when humidity levels get too high, moisture is building up on the plants and walls, forming whole colonies of molds, fungi, and mildews . Even if you had none of these developing before the high levels, the moisture would create the perfect environment for all of these to start developing, in a very short amount of time. These pathogens will destroy your garden if not taken care of immediately. This is one more reason why a controlled, closed loop, sealed room is the best way to build and run a grow room, as you can control every element of the environment with the right equipment.
2.3 Remote Sensing
The first aerial imagery dates to 1858 when Gaspaed Felex Tournachon took photos from a balloon . Most of the modern researchers refer to Remote Sensing as a new technology in agriculture, but literature shows it has been used in agricultural activities at least since 1927 when aerial photography was used to differentiate the healthy cotton plants from plants killed by cotton root rot disease . The use of satellites dates back to the 1960s but the use of satellite crop imagery, obtained from Landsat, began in 1978. Between the middle 1960s and the early 2000s, only five percent of satellites launched were associated with the applications of agricultural. The use of satellite and aerial images by industry for forecasting crop production, estimating damage from natural disasters and other aggregate information on crop growth is well established until now.
2.3.1 Potential Benefits of Remote Sensing Adoption in Agriculture
Farmers face loss billions a year as a result of fertility, insect, disease, weed and water problems. Farmers have relied on crop scouting to diagnose these problems, and then remedies were prescribed as blanket applications across whole fields. However, scouting is slow, labor intensive and very expensive. Blanket applications of fertilizers, pesticides, irrigation, and drainage cannot consider as the variability inherent in all natural environments. The benefits of RS were once thought to have been oversold . When the concerns regarding agriculture's role in surface and groundwater quality increase, there is renewed interest in using RS to more efficiently on how to manage fertilizers, pesticides, and water in fields. While RS application has been in existence for decades, its use on farms is still very low. Generally, technological change starts slowly, and increases linearly to a rapid growth . The adoption process involves five stages. The first stage is the knowledge about the technology . Second, persuasion of the value of the technology. Third, decision to adopt, four for implementation and five for the confirmation of the technology. Individuals who start the process are said to be risk takers because little is known about the value of the technology in the early of the stages. Factors that will enhance the adoption of the technology include trialability that can it be tried out. Observability are about the results can be observe or not. Relative advantage is about the better than present technology, complexity is about easy to use and compatibility is about the suitable for the circumstance or not . According to the complexity, RS provides large volume of data which frustrates many farmers, while its relative advantage over manual scouting would be increased their profit. Precision technology has been used in agriculture for many years but only a few of the applications such as yield monitoring are used by farmers. This application is one of the least used which could be attributed to the geography, the economics or the crop involved . However, remote sensing is believed to be popular on some high value crop and very large farms. At the farm level, the profitability of a new technology is increased revenue less additional costs that come with it . Revenue comes from increased yield and higher output price due to better marketing strategies and higher quality of the crops . Based on the remote sensing study, increased protein content in wheat resulted in higher gross revenue . The associated cost of remote sensing comes from imagery acquisition and analysis, and training to develop interpretation skills. Other risk should also be taken into account because the information provided by the technology could be not accurate or misinterpreted. Hence result in over or under application of inputs. Adoption of the remote sensing and other precision agricultural technologies are related because remote sensing provide some of the information needed for variable rate application, interpreting yield maps and others. The perception of remote sensing about the service providers is included because in as much as remote sensing should provide economic benefits to farmers, it should be profitable to the service providers as well to enable them stay in the business and provide the service. Their perception is key to the future of the technology. The key role of service providers is to transform remote sensing data into information that farmers can easily use.
2.3.2 Remote Sensing Application in Agriculture
Remote sensing can be divided into two categories, ground-based and airborne. During evaluating a remote sensing platform, spatial and spectral resolution must also be taken into account. The spatial resolution defines the pixel size of satellite or airborne images covering the earth surface and relates to the dimensions of the smallest object that can be recognized on the ground . A sensor\'s spectral resolution indicates the width of spectral bands in which the sensor can collect reflected radiance.
18.104.22.168 Ground-Based Remote Sensing
Based on research, the handheld remote sensing instruments are very useful for small-scale operational field monitoring of biotic and abiotic stress agents . This technology has better temporal, spectral, and spatial resolutions compare to airborne remote sensing. A limiting factor of handheld remote sensing is one of efficiency and often time reduced to evaluating small areas when compared with aircraft which can be used to be used to evaluate much larger areas at a time. Forecasting yield, nutritional requirements of plants, detection of pest damage, water demands and weed control are the most commonly undertaken problems in studies making use of opportunities of field spectrometers in agriculture.
22.214.171.124 Airborne Remote Sensing
Up to date, airborne remote sensing is mainly realized with the use of piloted aircrafts, but in recent years they are more often replaced by Unmanned Aerial Vehicles (UAVs), which are aircraft remotely piloted from a ground station. UAVs have a lot of advantages such as typically low cost, light weight and low airspeed aircrafts that are well suited for remotely sensed data gathering. Currently, there are two broad platforms for UAVs, namely the ‘Fixed Wing' and ‘Rotary Wing' types. Fixed wing UAVs have the advantage of being able to fly at high speeds for long durations with simpler aerodynamic features and some of them do not even require a runway or launcher for takeoff and landing. The rotary wing UAVs have the advantage of being able to take off and land vertically and hover over a target. However, it has some problems due to mechanical complexity and shortened battery power, they have a short flight range. In general, UAVs have several advantages; they can be deployed quickly and repeatedly, they are flexible in terms of flying height and timing of missions and they can obtain very high resolution imagery. This imagery allows for observation of individual plants, patches, gaps and patterns over the landscapes that have not previously been possible . UAVs with a typical spatial resolution of 1–20 cm could fill the resolution gap between piloted aircraft and the resolution of 0.2 to 2 m and ground-based platforms (< 1 cm) . Providing a swath width of 50–500 m and a spatial resolution of 1- 20 cm, UAV platforms may be able to provide high resolution inputs necessary for site-specific crop management. UAVs with a very high resolution might be used also in agronomical research, management of specialty crops and studies of the within-field variability. Various ultralight imaging systems, weighing about 100 g, have been developed to be used with UAVs in recent years. One of the lightest available multispectral camera is ADC Micro which weights 90 g and produces images in three channels: green (520-600 nm), red (630- 690 nm) and NIR (760-920 nm).
2.4 Unmanned Aerial Vehicle
An unmanned aerial vehicle (UAV) is an aircraft that carries no human pilot or passengers. UAV sometimes called “drones” that can be fully or partially autonomous but are more often controlled remotely by a human pilot.
2.4.1 UAV Platform
The UAV platform consists of hardware and the scientific payload. The UAV is comprised of low-cost which is easily available commercial off-the-shelf (COTS) components. The main purpose of the UAV is to safely fly the scientific payload for a minimum of ten minutes fly time. The platform is controlled by the pilot remotely from the ground station and has safety features programmed into it, such as a return to home function.
2.4.2 UAV Hardware
The main chassis for the UAV is the frame set. This features a diagonal wheelbase which is used to mount the UAV and payload hardware. The system is comprised of battery powered vertical take-off and landing (VTOL) UAV with motors. The motors and electronic speed controllers (ESC) were chosen to be able to deliver a strong lift and ability for the UAV to carry the payload without fail during the flight. The arms are constructed from material which is known to be resistant to breakage in case of crashing, while the diagonal wheelbase is base is constructed from PCB material. The landing gear used to avoid high crash. This is a high crash resistant landing gear usually made fromG10 and aluminum construction. G10 laminate grades are produced by inserting continuous glass woven fabric impregnated with an epoxy resin binder while forming the sheet under high pressure. This material is used exhibits excellent mechanical and dimensional stability (Polymer Plastics). The landing gear offers the space to mount equipment and has large aluminum rails for landing. A first-person-view system in installed on the UAV so that the co-pilot can ensure the UAV is over the intended spectral target. This is extremely useful when flying over coastlines to ensure the target area has been observed. The UAV is controlled through its attitude sensors. The operator\'s desired controls are processed through the onboard computer and then confirmed through the accompanying sensors. When the UAV is placed into attitude hold, the science platform is held in nadir-viewing position. The UAV pointing control mechanism is modeled after Quine\'s work where a microprocessor controller derives real-time estimates of gondola attitude, employing an extended filter to combine gyro, magnetometer, tilt-sensor, and shaft-encoder information.
2.4.3 UAV Design
A variety of flying vehicles is able to transport cameras and other sensors. Most common forms are small, electrically powered model planes with wingspans from 2 – 3 meters and multi- bzw helicopter. They are piloted by an operator via remote control, assisted by an autopilot on board as shown in Figure 2.1. Also often used are gas because lighter than air platforms or hot air carried platforms like balloons, aerial kites and paraglide with or without motor.
Figure 2.1: Autopilot on Board.
2.4.4 Layout of a UAV System
A UAV is the prominent part of a whole system that is necessary to fly the aircraft. Even though there is no pilot physically present in the aircraft, this does not mean that it flies automatically by itself. In many cases, responsibility of the crew for a UAV is larger than that of a conventional aircraft. The aircraft is controlled from the ground, Ground Control Station also known as GCS, so it needs reliable communication links to and from the aircraft, but also to the local Air Traffic Control (ATC) authorities if required, usually when flying higher than 150-200 m above the ground. The GCS provides a working space for a pilot, navigator, instrument operator and usually an important mission commander. The data received by the GCS from the instruments is either processed on-site or forwarded to a processing centre. This can be done using standard telecommunication means. Of course, when operating low-cost systems, most of the GCS functions can be combined in the handheld remote controls that are typical for these systems. In that case, there is no data transmission for the instrument; all data are stored on-board
2.4.5 UAV On Remote Sensing Instrument
Low altitude UAVs are used to carry light-weight instruments. Most of the cases, these consist of off-the-shelf component such as consumer digital cameras. At low altitude, it is possible to achieve very high resolution and it has been shown that consumer grade SLR cameras offer sufficient precision and stability to allow photogrammetric extraction of information . Other instruments include the combinations of imaging systems covering visible to thermal spectrum, with multi- or hyperspectral sampling, miniature RADAR and passive microwave radiometers [20, 21, 22, 23, 38]. On the other hand, UAVs are also used as a test bed for new instruments or integration of instruments . This is of significant importance, as it allows research groups that specialize in instrument design to test prototypes on a regular basis. At VITO, a high resolution wide swath digital camera is under development for flight on Mercator within the Pegasus project. This camera uses extremely light-weight subsystems to reduce the total mass to less than 2.5 kg and still generate 30 cm ground sampling distance from 18 km altitude . In short, UAVs have carried instruments that cover the whole range of the spectrum that remote sensing has addressed. Usually, however, it is not possible to carry the instruments that have been conceived for larger manned platforms, so innovative solutions have been found.
2.4.6 UAV on Remote Sensing Application
Many remote sensing applications have benefited from the use of UAVs. In most cases, this was due to the cost of the mission, the need for rapid response or the fact that observations need to be carried out in an environment that may be harmful or dangerous to an aircrew. A striking example is the adoption of remote sensing using UAVs in archaeology [24, 31, 37]. The main purpose is to document archaeological sites, and to provide ‘a bigger picture'. The accuracy requirements are not very high, although it has been shown that e.g.; elevation accuracy using a helicopter UAV and a consumer digital cameras yields elevation models that are comparable to ground laser scanner measurements. Vegetation monitoring has also been successfully done using UAVs. A HALE UAV, Pathfinder Plus was used to demonstrate this on a coffee plantation in Hawaii . Others have studied rangelands, and in Japan these systems are considered to be an integral part of farm equipment . Rapid response imaging using UAVs has received a lot of attention as well. This has been demonstrated for road accident simulations and in many cases of forest fire monitoring [25, 28, 30, 36]. UAVs have also been proposed as platforms to monitor volcanoes. A final example of the flexibility of UAVs is their use in traffic monitoring [26, 33].
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