Smart Irrigation System Using Moisture Sensor and Solar

Transcription

1 ISSN No: Smart Irrigation System Using Moisture Sensor and Solar Midhun.V. K, Midhun.V.S, Moideen Kutty.C.P, Faisal.P, K.C.Anandhan Dept. of Electrical and Electronics Engineering,SHREE VENKATESHWARA HI-TECH ENGINEERING COLLEGE Gobichettipalayam Erode District, Tamilnadu, India Received: 07/01/2017, Revised: 25/02/2017 and Accepted: 27/03/2017 Abstract The project is designed to develop an automatic irrigation system which switches the pump motor ON/OFF on sensing the moisture content of the soil. In the field of agriculture, use of proper method of irrigation is important. The advantage of using this method is to reduce human intervention and still ensure proper irrigation. The project uses an 8051 series microcontroller which is programmed to receive the input signal of varying moisture condition of the soil through the sensing arrangement. This is achieved by using an op-amp as comparator which acts as interface between the sensing arrangement and the microcontroller. Once the controller receives this signal, it generates an output that drives a relay for operating the water pump. An LCD display is also interfaced to the microcontroller to display status of the soil and water pump. The sensing arrangement is made by using two stiff metallic rods inserted into the field at a distance. Connections from the metallic rods are interfaced to the control unit. The concept in future can be enhanced by integrating GSM technology, such that whenever the water pump switches ON/OFF, an SMS is delivered to the concerned person regarding the status of the pump. We can also control the pump through SMS. 1. Introduction In the present era one of the greatest problems faced by the world is water scarcity and agriculture being a demanding occupation consumes plenty of water. Therefore a system is required that uses water judiciously. Smart irrigation systems estimate and measure diminution of existing plant moisture in order to operate an irrigation system, restoring water as needed while minimizing excess water use. The soil moisture based irrigation control. Uses Tensiometric and Volumetric techniques, which are relatively simple but these quantities are related through a soil water characteristic curve that is specific to a soil type. Also the sensors used require routine maintenance for proper performance. Intelligent automatic plant irrigation system concentrates watering plants regularly without human monitoring using a moisture sensor. The circuit is built around a comparator Op-amp (LM324) and a timer which drives a relay to switch on a motor. The system uses a hardware component, which is subjected to variation with the environmental conditions. A real-time wireless smart 101

2 sensor array for scheduling irrigation[3] prototyped a real-time, smart sensor array for measuring soil moisture and soil temperature that uses off-the-shelf components was developed and evaluated for scheduling irrigation in cotton. This system is specific for a crop and hence its usage is limited. Focus of Smart Irrigation System Then using a control circuit it is used to charge a battery. From the battery using converter circuit it gives power to the water pump which is submerged inside the well. Then the water is pumped into an overhead tank for storing water temporarily before releasing the water into the field. In automatic irrigation module the water outlet valve of the tank is electronically controlled Fig.2.1Overview of automatic irrigation module By a soil moisture sensing circuit. The sensor is placed in the field where the crop is being cultivated. The sensor converts the moisture content in the soil into equivalent voltage. This is given to a sensing circuit which has a reference voltage that can be adjusted by the farmer for setting different moisture levels for different crops. The amount of water needed for soil is proportional to the difference of these two voltages. A control signal was given to a stepper motor whose rotational angle is proportional to the difference in voltage. The stepper motor in turns controls the crosssectionalarea of the valve to be opened controlling flow of water. Therefore the amount of water flowing is proportional to the moisture difference. System Description Proposed irrigation system mainly consists of two modules- Solar pumping module and automatic irrigation module. In solar pumping module a solar panel of required specification is mounted near the pump set. Then using a control circuit it is used to charge a battery. From the battery using Converter circuit it gives power to the water pump which is submerged inside the well.then the water is pumped into an overhead tank for storing water temporarily before releasing the water into the field. In automatic irrigation module the water outlet valve of the tank is electronically controlled by a soil moisture sensing circuit. The sensor is placed in the field where the crop is being cultivated. The sensor converts the moisture content in the soil into equivalent voltage. This is given to a sensing circuit which has a reference voltage that can be adjusted by the 102

3 farmer for setting different moisture levels for different crops. The amount of water needed for soil is proportional to the Difference of these two voltages. A control signal was given to a stepper motor whose rotational angle is proportional to the difference in voltage. The stepper motor in turns controls the crosssectionalarea of the valve to be opened controlling flow of water. Fig.2.2.Block diagram of solar pumping module Basic Design For our mock-up we used materials that we found in the 350/450 lab room as well as materials we had collected from home and other design courses. Though it is not to scale we wanted to show the overall design of what our system would look like. As seen above there is a solar panel, the rectangle of duct tape, connected to the pump which is an old broken motor which feeds the storage tank which is just a cylindrical piece of foam. The pipes are drinking straws and Fig.2.3 Block Diagram Of Smart Irrigation System the drip tape is old bits of wire. This model shows how condensed the whole system could be depending on available 103

4 space in the existing garden Solar Panel, Charge Controller And Battery A solar panel pumps electricity into a battery that stores it, but the solar panel has no control over how much it does or how the battery receives it. The charge controller (charge regulator) positioned between the solar panel and the battery regulates the voltage and the current and essentially halts charging activity temporally when necessary. Solar panels are connected through an Array Combiner. Power Supply A 12V dc supply of battery is fed to the 7805 regulators which converts it into regulated 5V DC supply. It is then, distributed to all the driver and relay circuits. 5V is supplied to the microcontroller and to all ICs used in the system. Humidity Sensor The health of a plant is influenced by many factors, one of the most important being the monitors the moisture content of the soil. It consists of a connecting probe, which is laid down in the soil. It is used to sense the moisture of the soil and sends the signals to the controller. If the moisture level reaches the below the pre-set value, then the water is sent to the field. These sensors have no moving parts, they are precise, never wear out, do not need calibration, work under many environmental conditions, and are consistent between sensors and readings. Moreover, they are not expensive and quite easy to use using the DHT 11 sensor, monitoring of the temperature & Humidity at regular intervals, is done. When it exceeds the particular temperature, the circuit sends the signals to the microcontroller. Based on the error signal error, the decision of turning the motor ON/OFF takes place. Microcontroller-(ATMEGA8) ATMEGA8 is a robust, 8 bit microcontroller that suits for such outdoor applications.thereare32 8general purpose registers having fully static operation. It contains 28-pinpackage. The feature of ATMEGA8 is 5/2 EPROM data memory. It contains three ports namely port B,port C &Port D. Port B have 8-bit bi-directional I/O pins. Ports C have7-bit bit-directional I/O pins. Ports D have 8-bit bi-directional I/O pins. This is a very useful device, indeed. With it, we can easily multiply or divide voltage and current in AC circuits. Indeed, the transformer has made long-distance transmission of electric power a practical reality, as AC voltage can be stepped up and current stepped down for reduced wire resistance power losses along power lines connecting generating stations with loads. At either end (both the generator and at the loads), voltage levels are reduced by transformers for safer operation and less expensive equipment. A transformer that increases voltage from primary to secondary (more secondary winding turns than primary inducing turns) is called a step-up transformer. Conversely, a transformer designed to do just the opposite is called a step-down transformer. This is a step-down transformer, as 104

5 evidenced by the high turn count of the primary winding and the low turn count of the secondary. As a stepdown unit, this transformer converts high-voltage, low-current power into low-voltage, high-current power. Resistor & Transistor Many resistors are so small that it would be difficult to print their value and % tolerance on their body in digits. To overcome this, according system based on bands of distinctive colours was developed to assist in identification. Here we use five 10K ohm resistors Connected with the base of NPN transistor and five 470 ohm resistors connected with the LEDs which are further connected with the collector of NPN transistor. In our project we use five NPN transistors (BC 547) in which the emitter of each transistor is connected with the ground of voltage regulator and collector of each transistor is connected with the voltage regulator and moisture sensor through LEDs. Voltage Regulator A voltage regulator is designed to automatically maintain a constant voltage level. It may use an electromechanical mechanism, or electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages. In our project we use 5V voltage regulator of 7805 series which is use to convert the 6V power given from battery to 5V. Water Pump The method of flooding a garden for irrigation can put a lot of strain on the pump with the surges in electricity being as great as the power in the city is constantly being turned on and off. The proposed design would have a pump obtaining consistent power derived from the solar panel and would not be affected by power fluctuations in the grid as a controller could be implemented. Many of the pumps date back years and given Kazakhstan s economic ties with Russia a down surge in the economies make replacement UNlikely.The equipment is available but there are not many people with the expendable income to pay for them. With the consistent voltage and a newer pump, the pump will operate more efficiently than the one they were previously using.full-scale pump specifications are given as recommendations instead of a specific model as it is determined by the water demands and head loss calculations which are variable and dependent on the theoretical model which allows for various user input. A pump can be selected that has the flow rate capability as well as the power to draw from the water table in the area. Faced with the challenge of providing a pump based on conflicting data from REFRESCH and locals in Shekel, a calculator, which is adjustable for differing implementations, provides specifications for determining pump characteristics. Initial information about the water table suggests that it was located around feet but in the last few years that may have lowered. Therefore a pump needs to self-prime up to 4.5m and pump water an additional 3m above ground level to fill the water storage vessel. The Revco 12 Volt Self-priming pump will meet these requirements. 105

6 Fig.3.2.Block diagram of GSM based smart irrigation system Irradiance Data The development of the solar panel portion of our system requires data driven decisions. The decision to implement a solar panel as a power source is well justified by the country s irradiance levels ( kw/m2year) and because of the poor reliability of the electrical grid. Since it will be the main source of energy, it must have a mutual relationship with the devices it will power. With a pump selected power rating for a solar panel can be determined. Automatic Valve Regulation Fig.3.3 Solar Powered Irrigation System. For an automatic valve control we are using a stepper motor as an actuator control of the valve which is connected to the outlet valve of the tank. With the help of moisture sensor signal and a controller, a control pulses is 106

7 given to the driver circuit that excites the stepper motor. So this way the outlet valve is slowly opened or closed depending upon the amount of moisture present in the soil of the field When the soil moisture content reaches the required value, the valve is fully closed and power to driver circuit is killed and controller is put into sleep mode for low power consumption. When the moisture in soil is dried and reach a minimum cut-off value, the controller comes out of sleep mode and flow of water is regulated. This way the whole system works automatically. Design And Working In developing concepts to full fill our user s needs several design drivers became apparent. Two aspects critical to the design were the solar panel and the water pump. While these features are absolutely necessary to irrigate the garden without power from the electrical grid, their specifications are both determined by the amount of water necessary to irrigate the given garden. Determining irrigation lines and storage that adequately waters the garden poses the largest challenge. This system will have to distribute the water utilizing cheap and locally available resources while also providing water storage during times when solar power is not available. Concept of Generation Developing concepts for the solar-powered irrigation system was done as individually and in a group during brainstorming sessions. Some research was conducted before these sessions to understand all of the components that would be required in the implementation of an irrigation system. Some of these factors such as a photovoltaic solar panel, water pump, and an inverter/controller are crucial to the design requirements as they accomplish our task and add some control to the system. With the major components and user requirements in mind, functional decomposition was performed to lay out the critical actions that the various components would need to perform (see appendix for Functional Decomposition). The Component with the most flexibility in implementation would be the irrigation system attached to the water pump. Spray, furrow, flooding, above and below ground drip systems were the major concepts analysed. While they all have their advantages and disadvantages one unique system is well suited for the particular climate, crop, cost, and size of the system being modelled for Shekel, Kazakhstan. For our mock-up we used materials that we found in the 350/450 lab room as well as materials we had collected from home and other design courses. Though it is not to scale we wanted to show the overall design of what our system would look like.as seen above there is a solar panel, the rectangle of duct tape, connected to the pump which is an old broken motor which feeds the storage tank which is just a cylindrical piece of foam. The pipes are drinking straws and the drip tape is old bits of wire. This model shows how condensed the whole system could be depending on available space in the existing garden. 107

8 Implimentation For the implementation of the proposed system we are using a 2 HP water pump and various modules which are designed and fabricated separately and then finally they are assembled together to implement the proposed system. Solar energy is harnessed using solar panel PVL-68 that generates 53W at Nominal Operating Cell Temperature. It is 24V, amorphous silicon type solar cell. Specification of the solar panel selected: Array capacity --240Wp Irradiance 580 W/m2 Open circuit voltage 18.1 V Short circuit current 3.98 A Load test on a solar panel have been conducted and its maximum and minimum Value is tabulated. Working Fig.4.2Basic Representation of Smart Irrigation System. Converting Sunlight into Electricity Light striking a silicon semiconductor causes electrons to flow, creating electricity. Solar power generating systems take advantage of this property to convert sunlight directly into electrical energy. Solar panels (also called solar modules ) produce direct current (DC), which goes through a power inverter to become..alternating current (AC) electricity that we can use in the home or office, like that supplied by a utility power company. There are two types of solar power generating systems: grid-connected systems, which are connected to the commercial power infrastructure; and stand-alone systems, which feed electricity to a facility for immediate use, or to a battery for storage. Grid-connected systems are used for homes, public facilities such as schools and hospitals, and commercial facilities such as offices and shopping centres. Electricity generated during the daytime can be used right away, and in some cases surplus electricity can be sold to the utility power company. If the system doesn t generate enough electricity, or generates none at all (for example, on a cloudy or rainy day, or at night) electricity is purchased from 108

9 the utility power company. Power production levels and surplus selling can be checked in real time on a monitor, an effective way to gauge daily energy consumption. Stand-alone systems are used in a variety of applications, including emergency power supply and remote power where traditional infrastructure is unavailable. Irrigation Irrigation system uses valves to turn irrigation ON and OFF. These valves may be easily automated by using controllers and solenoids. Automating farm or nurseryirrigation allows farmers to apply the right amount of water at the right time, regardless of the availability of labour to turn valves on and off. In addition, farmers using automation equipment are able to reduce runoff from over watering saturated soils, avoid irrigating at the wrong time of day, which will improve crop performance by ensuring adequate water and nutrients when needed. Automatic Drip Irrigation is a valuable tool for accurate control in highly specialized greenhouse vegetable production and it is a simple, precise method for irrigation. It also helps in time saving, removal of human error in adjusting available soil moisture levels and to maximize their net profits. Irrigation is the artificial application of water to the soil usually for assisting in growing crops. In crop production it is mainly used in dry areas and in periods of rainfall shortfalls, but also to protect plants against frost. Tests Used and Scope In developing concepts to full fill our user s needs several design drivers became apparent. Two aspects critical to the design were the solar panel and the water pump. While these features are absolutely necessary to irrigate the garden without power from the electrical grid, their specifications are both determined by the amount of water necessary to irrigate the given garden. Determining irrigation lines and storage that adequately waters the garden poses the largest challenge. This system will have to distribute the water utilizing cheap and locally available resources while also providing water storage during times when solar power is not available. Project Scope Due to time restrictions and project limitations due to the geographical barrier between us and our proposed implementation site we have chosen to orient this project to accomplishing two goals. First is the development of a mathematical model that outputs relevant design criteria based on user input and can be adapted to a diverse set of implementation criteria. The second is the construction of a scaled model that acts as not only a proof of concept but a means to substantiate and test the model s predictions for hardware requirements. These two components of our project scope give insight into the requirements for building a full-scale solar-power irrigation system. To accomplish these goals we first examine different full-scale design concepts and choose a final design to which we can identify key design drivers, create a theoretical model based on engineering analysis and thereby design and build a scale prototype for 109

10 empirical testing and analysis Future Scope Future options of this project can be very diverse. We suggest collaboration with the University student group BLUE lab, as they have resources and experience working with human cantered engineering. We also feel an additional needs assessment should be conducted on the implementation site, and local area to gauge interest. A revaluation of whether a drip irrigation system is appropriate or not should also be done based mainly on the property size, as these systems are typically implemented on larger scales. This is mentioned because of the possibility of a small site of implementation. There is also some risk implementing an expensive system in a private residential property. The household can move or decide they are no longer interested in utilizing the system. Some collaboration with the city itself or a local school system could provide larger participation andinterest in the project, expanding the benefits of such an expensive system Conclusion With over nine hundred thousand tube wells being used in every state of India, around Rs.18 Million of energy is used for pumping water for irrigation. This amount of money used for electricity can be saved with the help of solar water pump. Annually the cost of nearly five million kilo watt hour of energy can be spared. That is around Rs.27 Million per annum can be redeemed which comes around 40% of the total amount of investment. Even though the initial Investment is high, it can be earned back in 2 and a half years time. If we assume the cost of power is Rs. 1.5 Million per kilo watt hour, Rs.18 Million is used for pumping water alone in a year. By using the solar water pump, we can save up to 4.8 million KWh of energy annually which saves a lot of energy. The excess energy can also be given to the grid with small Modifications and investments in the circuit, which can add to the revenue of the farmer. By implementing the proposed system there are various benefits for the government and the farmers. For the government a solution for energy crisis is proposed. By using the automatic irrigation system it optimizes the usage of water by reducing wastage and reduces the human intervention for farmers. The excess energy produced using solar panels can also be given to the grid with small modifications in the system circuit, which can be a source of the revenue of the farmer, thus encouraging farming in India and same time giving a solution for energy crisis. Proposed system is easy to implement and Environment friendly solution for irrigating fields. The system was found to be successful when implemented for bore holes as they pump over the whole day. Solar pumps also offer clean solutions with no danger of borehole contamination. The system requires minimal maintenance and attention as they are self starting. To further enhance the daily pumping rates tracking arrays can be implemented. This system demonstrates the feasibility and application of using solar PV to provide energy for the pumping requirements for sprinkler irrigation. Even though there is a high capital investment required for this system to be implemented, the overall benefits are high and in long run this 110

11 system is economical. References 1. Garg, H.P Advances in solar energy technology, Volume 3. Redial Publishing Boston, MA. 2. Hal crow, S.W. and Partners Small-scale solar powered irrigation Pumping systems: technical and economic review. UNDP Project GLO/78/004.Intermediate Technology Power,London, UK.A. Harman et al., Mathematical modelling of a box-type solar cooker employing an asymmetric compound parabolic concentrator, Solar Energy, vol.86, pp , K. K. Tse, M. T. Ho, H. S.-H. Chung, and S. Y. Hui, A novel maximum Power point tracker for PV panels using switching frequency modulation, IEEE Trans. Power Electron, vol. 17, no. 6, pp , Nov Haley, M, and M. D. Dukes Evaluation of sensor -based residential irrigation water application. ASABE 2007 Annual International Meeting, Minneapolis, Minnesota, ASABE Paper No [5] Prakash Persada, Nadine Sangsterb, Edward Cumberbatchc, Aneil Ramkhalawand and AtamanMaharaja, Investigating the Feasibility of Solar Powered Irrigation for Food Crop Production: A Caroni Case," ISSN The Journal of the Association of Professional Engineers of Trinidad and Tobago, Vol.40, No.2, pp.61-65, October/November