ABSTRACTNew irrigation electrical control technologies could improve irrigation efficiency, promoting waterconservation and reducing the environmental impacts. The objectives of t his project was to avoid wastage of water and increase irrigation efficiency by using control based irrigation system with the help of soil moisture sensor, rain sensor, wind speed sensor and light intensity sensor. The project presented here will water plants regularly in accordance with the state of soil moisture, light intensity, wind strength and presence of rain fall. Water mark moisture sensor is inserted in the soil to sense whether the soil is wet or dry. The comparator monitors the sensors and when moisture sensor senses the dry condition then the circuit will switch on the motor at which the factors light intensity, rain fall and wind speed are in normal conditions and it will switch off the motor when the moisture sensor senses the wetness or dryness of the soil at which one or two or three of the factors are inabnormal conditions. The comparator does the above job when it receives the signal from the sensors.

All conditions that can be controlled by sensors based on the signals from those different factors that affects irrigation. Solonoid valves are used to control the water flow. It also improves the traditional irrigation system in Ethiopia enabling the irrigation system to have high efficiency and low water usage. The existing irrigation system is tedious, time consuming and very wasteful in water usage.

The controlled based sprinkler irrigation system gives the best feature than the traditional one.

CHAPTER ONE1 INTRODUCTION

1.1 Background of the project

Debremarkos town has good ground water potential due to itsweather conditions. But due to lack of water storage capacity and large spatial, temporal variations of rainfall, due to this there is no enough water for our university to planting green house continuously and there are lack of water pumping available in the town. Therefore, the water supply of the town still now insufficient. Our university’s water supply also depend on the town water supply. The Debre Markos University has green house to planting the coumpound and it has an

area which is still now 4066 meter squar,but it will be increase for the future.The university has its own plan to change the compound into green feature for a short period of time. The interesting of the project to operate automatical system to eliminate the necessity of laborforce and it uses widely in our country for the future to farm irrigation technology.

The Ethiopian government has recognized Ethiopia’s irrigation potential and has identified the important role of irrigation develop rain fall distribution and at the same time addressing poverty reduction of the country. In Ethiopia the irrigation plays an important role in the development of the country’s economy.

On the other hand labor force are wasting water abundantly without proper management .This leads to the scarcity of water at the time of requirement. Irrigation is the key to a successful green house investment.The grounds men arguments presented play a very important role in the pursuit to improve the irrigation system of Debre Markos University.The relevant facts about the irrigation status of the University and the impact of the green feature of the campace andthe environment may have tremendous effect to the University stability.Therefore,the compelling evidence of the challenges posed by this current phenomenon motivated the conduct of the study to design automatic control irrigation system.

1.2 Statement of the problem

Irrigation system in Debre Markos Universty has done for two years which is traditional. These irrigation systems have many drawbacks like wastage of water, high Labor cost,timing problem, uniformity of water supply, so that each plant will not get the amount of water it needs either too much or too little. Since the system is Uncontrolled thesoil is soaked too much. Therefore, the moisture of the soil that determines the amount of water in soil must be Checked regularly to prevent the plant from wilting or in the worst case it might die. Besides, each species of the plant have its own characteristic. So, the consumption of water is different following their type. These systems have low requirement for infrastructure and technical equipment but Need high labor input, so our project comes up with a remedy to solve the above Problem with high efficiency and low water wastage. In order to maintain the condition and overcome the problem, Automatic Plant Irrigation System is used. This system is created to reduce the time by using automatic system rather than manual way of watering. An automatic plant irrigation system will provide proper and moderate irrigation system for the university in low costalmost no man power for plant irrigation and it will increase also productivity of the green house.

1.3 Motivation

The motivation for this project came from the green house of the university where Horticulture (flowers) to decorate the campus based on features, but the climatic conditions lead to lack of rains and scarcity of water. The main aim of this paper is to provide automatic irrigation to the plants which helps in saving money and water. The grounds men working in the irrigationlands are solely dependent on the rains and bore wells for

irrigation of the land. Even if the irrigation land has a water- pump, manual intervention by grounds men is required to watering whenever needed.

1.4 Objective of the study

The general objective of the study is to design and develop an automatic water pump and irrigation system of green house of the university through power circuit with control circuit. The specific objectives are to design an automatic water pump and irrigation system that utilities electro –mechanical equipment, solenoid valves and sensors. The general objective of the project to minimize thelabor force, increasing the productivity of green house and shortage of water resource etc.The specific objectives are: To design an automated green irrigation system that

utilizes electro-mechanical equipment, solenoid valvesand sensors.

To develop the pre-established design parameter and controlled components according to its technical purposes.

To solve the problems on manual irrigation system. To increase agricultural production by providing this

technology to stake holders. To reduce water wastage and human power.

1.5 Scope of project

The study outlines the design and development of an automated green house irrigation system that employs control switching through sensors. The project inhibits the conduct of the following in the entire scope of the study:

Implementation of the project to real green house application.

Determination of sunlight availability index in the region.

Determination of rainfall index. Determination of wind speed index. Determining the moisture level of the soil in

relation with resistance value. Developing and designing of controlling and

regulator circuits. Interconnecting circuits together for a single

task.

1.6 Limitations

As we have seen throughout the development of this study, the system must be suffered from the following limitations/challenges.

After the plant is irrigated, there may be a rainfall on the farm.

The higher speed of the wind will be exercised for a long period of time even when the soil is dry and the system cannot irrigate the farm.

The sprinkler irrigation cannot irrigate the farm uniformly due to the difficulty of sprinkler spacing and there will be wrong information to be fetched by watermark moisture sensor.

During cultivation, harvesting and weeding time the system may irrigate the farm and this leads to human intervention to the system.

There may be high evaporation when there is high light intensity/high soil radiation after the farm is irrigated.

The irrigated green house will not be irrigated uniformly due to the structure of the irrigated area.

Shortage of water reservoir.

1.7 Significance of the study

The proposed study will offer green house irrigation solution to the local planted providing Improvement to conventional irrigation using automatic control system. The application of automation technology to green house irrigation paves the way for an efficient and productive green house across the university there by provides significant economic Impact. Moreover, the technology adopted also provides potent technology transfer to various academic and technical institutions in the university through which training and joint of other university may be enhanced.

CHAPTER TWOLITERATURE REVIEW2.1 Review of related literature

The importance of the foregoing is crucial to the content of the research project. The related literatures and

similar studies mentioned in this study substantiate the arguments

that support the theories and assumptions therein. The information gathered in this chapter helps provide compelling motivation to pursue the conduct of the study due to the benchmark information and baseline research that reflect meritorious works and scholarly studies conducted by experts that are relevant to green house irrigation.

2.2 Automatic green house irrigation review

An automated irrigation system refers to the operation of the system with no or just a minimum manual intervention apart from field surveillance which requires human critical thinking. Almost every system (drip, sprinkler, surface) can be automatic with the help of control circuit,sensors and some electro-mechanical devices. It makes the irrigation process more efficient and workers can concentrate on other important farming tasks. On the other hand, such a system can be expensive and very complex in its design and may needs experts to plan and implement it.

2.3 Electrical and Electromechanical Components

2.3.1 Sensor

A Sensor is a device, which responds to an input quantity by generating a functionally related output usually in the

form of an electrical or optical signal. A Sensor converts the physical parameter (temperature, pressure, humidity, speed, flow, level, etc.) into a signal which can be measured electrically. Figure 2.1 shows the sensing processin terms of energy conversion. The form of the output signal will often be a voltage analogous to the input signal, though sometimes it may be a wave form whose frequency is proportional to the input or a pulse train containing the information in some other form.

Fig. 2.1The signal conversion of sensors

A) Moisture Sensor

Soil moisture sensors measure the water content in soil. Asoil moisture probe is made up of multiple soil moisturesensors. A patented watermark sensor showed in Figure 2.2is a solid-state electrical resistance sensing device thatis used to measure soil water

tension. As the tension changes with water content theresistance changes as well. That resistance can be measuredusing the watermark sensor. The sensor consists of a pairof highly corrosion resistant electrodes that are imbeddedwithin a granular matrix. A current is applied to thewatermark sensor to obtain a resistance value. Thewatermark sensor meter or monitor correlates the resistanceto centibars (cb) or kilopascals (kPa) of soil watertension. The watermark sensor is designed to be a permanentsensor, placed in the soil to be monitored and “read” asoften as necessary with a portable or stationary device.Internally installed gypsum provides some buffering for theeffect of salinity levels normally found in irrigatedagricultural crops and landscapes (irrometer.com, 2009)[7].

Fig.2.2Water mark moisture sensor

B) LDR (light dependent resistor) Sensor

Photo resistors as shown in Figure 2.3 also known as lightdependent resistors (LDR) are light sensitive devices mostoften used to indicate the presence or absence of light, to

1MΩ, but when the LDR sensor is exposed to light, theresistance drops dramatically, even down to a few ohms,depending on the light intensity. LDRs have a sensitivitythat varies with the wavelength of the light applied andare nonlinear devices. They are used in many applicationsbut are sometimes made obsolete by other devices such asphotodiodes and phototransistors. Some countries havebanned LDRs made of lead or cadmium over environmentalsafety concerns (resistorguide.com, 2009)[8].

Fig2.3 light dependent resistor

C) Rain Sensor

A rain sensor or rain switch as shown in Figure 2.4 is aswitching device activated by rainfall. There are two mainapplications for rain sensors. The first is a waterconservation device connected to an automatic irrigationsystem that causes the system to shut down in the event ofrainfall. The second is a device used to protect theinterior of an automobile from rain and to support theautomatic mode of wipers. Rain sensor works on the principleof conductivity. Two electrodes are positioned a certaindistance from the bottom of the basin. When the water levelreaches the electrodes a circuit is completed and theswitch is tripped. The weight of debris will not trip theswitch, but it still displaces water causing the switch totrip prematurely during a brief shower(sprinklerwarehouse.com, 2010)[9].

Fig.2.4Rain sensor

D) Wind Sensor

By using dynamo coupled with anemometer or other turbine,

the speed of the wind can be measured in terms of voltage.

The wind speed sensor as shown in Figure 2.5 depicts an

anemometer which also serves as a wind power generator. By

measuring the voltage from the dynamo we can determine the

speed of local air.

wind turns the cups and the generator to generate a voltage proportional to the instantaneous wind speed. Thistype of anemometer is located in an exposed position on a tower and is connected to control circuit through cables, and controlling mechanism from remote locations is possible. The greatest distance between the anemometer andthe control circuit depends on the electrical resistance of the cable and the design. This type of anemometer does not require a power supply for the main unit (Japan Meteorological Agency, 2011)[10].

Fig.2.5 Dynamo coupled anemometer

2.3.2 Variable Resistor

A variable resistor shown in Figure 2.6 is a device that is

used to change the resistance according to our needs in an

electronic circuit. It can be used as a three terminal as

well as a two terminal device. Mostly they are used as a

three terminal device. Variable resistors are mostly used for

device calibration (circuitstoday.com, 2013)[11].

Fig.2.6Variable resistor

2.3.3 Resistor

A resistor as shown in Figure 2.7 is a two-terminal electric circuit component that offers opposition to an electric current. Resistors are available in several common forms: wire wound resistors are formed from windings of fine wire; film resistors, commonly found in consumer electronic devices, use lengths of carbon or metal film deposited on a resistive base; and carbon-composition resistors use a bonded mass of carbon powder with a phenolic binder. Resistors absorb power from a circuit and convert it into heat; they are normally rated for the maximum amount of power that they can safely handle. Special resistors are also produced for the integrated circuit.

Fig.2.7 Resistor

Resistor values in ohms are usually shown as an adjacentnumber, and if several resistors are present in a circuit, they will be labeled with a unique identifier

number such as R1, R2, R3 (allaboutcircuits.com, 2013) [12].

2.3.4 Relay

A relay as shown in Figure 2.8 is a switch that open andclose circuits electromechanically or electronically.Relays control one electrical circuit by opening andclosing contacts in another circuit. The relay allows theisolation of two separate sections of the system with twodifferent voltage sources i.e., a small amount ofvoltage/current on one side can handle a large amount ofvoltage/current on the other side but there is no chancethat these two voltages are mix up. This is in the range ofa few volts to hundreds of volts, while the current can befrom a few amps to 40A or more, depends on the relay. Asrelay diagrams show, when a relay contact is normally open(NO), there is an open contact when the relay is notenergized. When a relay contact is Normally Closed (NC),there is a closed contact when the relay is not energized.In either case, applying electrical current to the contactswill change their state. Relays are generally used toswitch smaller currents in a control circuit and do notusually control power consuming devices except for smallmotors and Solenoids that draw low amps (galco.com, 2013).

Fig.2.8 Relay

2.3.5 AC motor

An AC motor as shown in Figure 2.9 is an electric motordriven by an alternating current (AC). AC motors come intwo types which are synchronous motors and inductionmotors. The AC motors are used differently based on whattype of AC motor it is. There are two types of AC motors,depending on the type of rotor used. The first is thesynchronous motor, which rotates exactly at the supplyfrequency or a sub multiple of the supply frequency. Themagnetic field on the rotor is either generated by currentdelivered through slip rings or by a permanent magnet. Thesecond type is the induction motor, which runs slightlyslower than the supply frequency. The magnetic field on therotor of this motor is created by an induced current. Theamount of power given off by an AC motor is determined bythe amount of power needed to operate the system. An ACmotor has two parts. A Stationary stator having coilssupplied within current to produce a rotating magneticfield, and rotor attached to the output shaft that is givena torque by the rotating field.

INDUCTION MOTORS

The AC induction motor is a common form of asynchronousmotor whose operation depends on three electromagneticphenomena:

Motor Action - When an iron rod (or other magneticmaterial) is suspended in a magnetic field so that itis free to rotate, it will align itself with thefield. If the

magnetic field is moving or rotating, the iron rodwill move with the moving field so as to maintainalignment.

Rotating Field - A rotating magnetic field can becreated from fixed stator poles by driving each pole-pair from a different phase of the alternating currentSupply.

Transformer Action - The current in the rotor windingsis induced from the current in the stator windings,avoiding the need for a direct connection from the Power source to the rotating windings.

Induction motors have either wound rotors or squirrel cage rotors.

Wound Rotor: Wound rotors are constructed using thesame principle asStator construction.

Squirrel Cage Rotor: - The SCIM rotor has conducting bars embedded in grooves that are etchedin the surface of the rotor along the direction of the rotor axis. The conducting bars are placed around. To allow current flowing the bars, the barsare shorted at either end of the rotor by large shorting rings. Squirrel cage rotor constriction isshown figure below. The grid constriction of this type of rotor contributes significantly to the robustness of the SCIM.

Generally, one of the major advantages of the inductionmotor is that it does not need a commutation. Inductionmotors are therefore simple, robust, reliable, maintenancefree and relatively low cost. They are normally constantspeed devices whose speed is proportional to the mainsfrequency.

Fig.2.9 AC motor

2.3.6 Solenoid Valve

A solenoid valve is an electromechanical device used for controlling liquid or gas flow. The solenoid valve is controlled by electrical current, which is run through a coil. When the coil is energized, a magnetic field is created; causing a plunger inside the coil to move. The solenoid valve uses an electric current which moves the solenoid. This pulls a piston preventing it from stopping the flow of air and fluid. The valve will need a constant flow of electrical current to remain open because when there is no current flow, the electromagnetic field scatters and the valve returns to its original position. Depending on the design of the valve, the plunger will either open or close the valve. When electrical current is removed from the coil, the valve will return to its de-energized state. The valve shown in Figure 2.10 is a normally-closed (NC), direct-acting valve. This type of solenoid valve has the most simple and easy to understand principle of operation.

Fig.2.10 solenoid valve

working principle Solenoid Valve

The media controlled by the solenoid valve enters the valve through the inlet port (Part 2 in the illustration above). The media must flow through the orifice (9) before continuing into the outlet port (3). The orifice is closed and opened by the plunger (7).

The valve pictured above is a normally-closed solenoid valve. Normally-closed valves use a spring (8) which pressesthe plunger tip against the opening of the orifice. The sealing material at the tip ofthe plunger keeps the media from entering the orifice, until the plunger is lifted upby an electromagnetic field created by the coil.

2.4 Mechanical Components

2.4.1 Water Tank/Reservoir

A water tank/reservoir shown in Figure 2.11 is a container for storing water. The need for a water tank is providing storage of water for green house irrigation. Various materials are used for making a water tank: plastics, fiber glass, concrete, stone, steel and earthen ponds function as water storage.

Fig.2.11 Water Tanker/Reservoir

2.4.2 Water Sprinkler

In the sprinkler method of irrigation, water is sprayedinto the air and allowed to fall on the ground surfacesomewhat resembling rainfall. The spray is developed by theflow of water under pressure through small orifices ornozzles. The pressure is usually obtained by pumping. Withcareful selection of nozzle sizes, operating pressures andsprinkler spacing, the amount of irrigation water requiredto refill the crop root zone can be applied nearlyuniformly at a rate suit to the infiltration rate of thesoil, thereby obtaining efficient irrigation. Figure2.12.shows a water sprinkler.

Fig.2.12 Water sprinklers

2.4.3 Water Pipe

Water pipes are pipes or tubes, frequently made ofpolyvinyl chloride (PVC/up), ductile iron, steel, castiron, polypropylene, polyethylene, copper, or (formerly)lead, that carry pressurized and treated fresh water tobuildings (as part of a municipal water system), as well asinside the building. Figure 2.13 depicts a PVC pipe used inlow-cost irrigation system.

Fig.2.13 PVC Water Pipes

2.4.4 Intake Water Screening System

Intake screens are designed to remove floating or suspendeddebris in a channel of flowing water. They protect pumpsand other downstream equipment from debris in surface waterintakes and other applications.

Initially wood chips, leaves, aquatic plants and floatingimpurities are removed by the screening process. After thescreening, a more compact suspended material will beremoved to allow water to flow through the chamber in whichit will settle to the bottom. Restrict the entry ofsuspended solids such as garbage in the water treatmentplant. Prevent pump, pipe and equipment from clogging ordamage. It launched a water course for the next process.

Fig.2.14 Intake water screening system

2.5 Soil Water Measurement

Soil water can be measured or estimated in a variety of

ways ranging from the simple, low cost hand-feel method tomore accurate and expensive neutron probe units. For mostirrigation water management applications, even a low cost,economical method is better than entirely foregoing soilwater measurement.

2.6 Types of Sprinkler Systems

1. Rotating head system: Nozzles placed on riser pipesand fixed at uniform interval. The most common device torotate the sprinkler heads is with a small hammer activatedby the thrust of water striking against the vane.

2. Perforated pipe system: Consists of holes perforatedin the lateral irrigation pipes in a specially designedpattern to distribute water fairly uniform.

Classification of sprinkler irrigation systems

1. Permanent systems: Are those having the pipespermanently located. Usually they are built and notinterfere with tillage operations. Installation costs aremuch higher, but labor and maintenance costs are less.

2. Semi-permanent: Usually have the main lines buried andthe laterals portable. The water supply is from fixedpoint. Installation costs are somewhat less than thepermanent system, but lab our and maintenance costs aremore.

3. Portable system: Have both main lines and lateralsportable Installation costs are less, but lab our andmaintenance costs are higher. These systems are designed tobe moved around the farm from field or even from farm tofarm.

Components of sprinklersystem A. Pumping unit

The pumping unit is required to lift the water from thewater source drawn from either open wells or bore wells anddistribute the water through the network of pipe line.

B. Main pipe line

Main pipe line may be permanent or portable. Permanentpipeline are used on the farms where boundaries are fixedand crops require full-season irrigation.

C. Lateral pipe lines

The lateral pipe lines are usually portable. A quickcoupled aluminum pipe is the Best for most portablelaterals. The lateral pipes are available in lengths of5, 60r 12 m.

D. Risers

Risers are small GI pipes fixed to the lateral pipes atsprinkler spacing. On top of the riser, the sprinkler headsare fixed. The size and length of riser will be decidedbased on pressure consideration and discharge.

E. Sprinkler head

Sprinkler head is the critical component of a sprinklerirrigation system. The suitability and efficiency ofsprinkler system depends on the operating characteristicsof sprinkler head. The operating characteristics ofsprinkler head are affected by varying pressure and wind

velocities.

2.7 Power Supply

The input to the controlling circuit is applied from theregulated power supply. The ac input i.e., 230v from themains supply is step down by the transformer to 12v and isfed to a rectifier. The output obtained from the rectifieris a pulsating dc voltage. So in order to get a pure dcvoltage, the output voltage from the rectifier is fed to afilter to remove any ac components present even afterrectification. Now, this voltage is given to a voltageregulator to obtain a pure constant dc voltage.

Fig.2.15 schematic diagram of power supply for control circuit

2.8 Transformer

Usually, DC voltages are required to operate various

electronic equipment and these voltages are 5v, 9v or 12v.But these voltages cannot be obtained directly. Thus the acinput available at the mains supply i.e., 230 is to bebrought down to the required voltage level. This is done bya transformer. Thus, a step down transformer is employed todecrease the voltage to a required level as shown in thefigure 2.16 below.

Fig 2.16 Step-down transformer

2.9 Rectifier

The output from the transformer is fed to the rectifier. Itconverts AC into pulsating DC.The rectifier may be a half wave or a full wave rectifier.In this project, a bridge rectifier is used because of itsmerits like good stability and full wave rectification.

Fig.2.17 Bridge rectifier circuit

The bridge rectifier is a circuit, which converts an ACvoltage to DC voltage using both half cycles of the inputAC voltage. The bridge rectifier circuit is shown in thefigure. The circuit has four diodes connected to form abridge. The AC input voltage is applied to the diagonallyopposite ends of the bridge. The load resistance isconnected between the other two ends of the bridge. For the

positive half cycle of the input AC voltage, diodes D1 and

D3 conduct, whereas diodes D2 and D4 remain in the OFFstate. The conducting diodes will be in series with the

load resistance RL and hence the load current flows through

RL. For negative half cycle the input AC voltage of the ACvoltage, diode D2 and D4 conduct whereas, D1 and D3 remainOFF. The conducting

Diodes D2 and D4 will be in series with the load resistanceRL and hence the current flows through RL in the samedirection as in the previous half cycle. Thus a bi-directional wave is the converted into unidirectional wave.

Fig.2.18 Bridge rectifier output voltage/currentwaveforms

2.10 Filter

Capacitive filter is used in this project. It removes theripples from the output of rectifier and smoothens the DCoutput received from this filter is constant until themains voltage and load is maintained constant. However, ifeither of the two is varied, DC voltage received at thispoint changes. Therefore a regulator is applied at theoutput stage.

Fig.2.19 Power supply with simple capacitor filter

2.11 Voltage Regulator

Voltage regulator is an electrical or electronic device that maintains the voltage of a power source within acceptable limits. The voltage regulator is needed to keepvoltages within the prescribed range that can be toleratedby the electrical equipment using that voltage. Voltage regulators are used in electronic equipment in which excessive variations in voltage would be detrimental.

Electronic voltage regulators utilize solid-state semiconductor devices to smooth out variations in the flowof current. In most cases, they operate as variable resistances; that is, resistance decreases when the

electrical load is heavy and increases when the load is lighter.

As the name itself implies, it regulates the input appliedto it. A voltage regulator is an electrical regulatordesigned to automatically maintain a constant voltagelevel. In this project, power supply of 12v is required. Inorder to obtain this voltage level, 7812 voltage regulatoris to be used. The first number 78 represents positivesupply and the number 12 represents the required outputvoltage levels.

Fig.2.20 voltage regulater

CHAPTER THREE

MATERIALS AND METHODOLOGY

3.1 Materials

The materials we have used in our project are websites;which we go through different books, journals and ongoingprojects in automatic green house irrigation system. Fromthis we are going to select appropriate rating of op amp,transistor, solenoid valve, dynamo, resistors, relays,sensors and limit switch based on their application inautomatic green house irrigation system and analyzedvalues.

3.2 Methodology

Data Collection: In this part data used for thisproject are discussed .The moisture level versusequivalent resistance measurement, lux levels versusthe light intensity, specification of component,resources taken from website, etc, are collected anddiscussed.

Literature review: In this section we have discussed,automatic irrigation review, methods of automaticgreen house irrigation, explanation of componentcommonly used in automatic green house irrigationsystem.

3.3 Power Circuit for Water Pumping Motor

The irrigation system is driven by an AC motor-based centrifugalpump which pumps water from the water reservoir to pressurize thewater sprinklers distributed in the green house irrigated areas.The irrigation system does not use gravitational force toirrigate the greenland, instead utilizes the pump to providepressure into the water sprinklers. Each water sprinklers areproperly spaced so as to cover consistent irrigated areas.Figure 3.1 Shows the power circuit of the motor-driven pumpconnected with proper safety measures to protect the prime moversfrom untoward situation. The contactor relay RL5 serves as theexternal relay that switches once desired according to thesystems operation requirements.

R

S

T

G

.

R

O.L

3- M ⏀Fig.3.1 power circuit of the irrigating pumpP

NC Lightintensity sensor

NC Moisturesensor Maximum level Sensor Minimum NC level 24v sensor NC Rain sensor (NO) NC Wind sensor

Solenoid valve (No. 1) NC Relay

Solenoid Valve (No.2)

N Fig. 3.2 Control circuit of pump motor and water reservoir

In the above control circuit, there are six input devices/sensorsthat plays very significant role in the system’s operation. Themost is the soil moisture sensor that measures resistance througha watermark moisture sensor. The second input device is the lightsensor (light dependent resistor) where the switching of the irrigation system depends upon theintensity of light. The third input device utilizes the windsensor which measures the appropriate wind speed that is used totrigger the relay.The fourth input device/sensor utilizes therain sensor provides appropriate switching or trigger the relay.The other two level sensors (Maximum and Minimum) utilizes thewater level of the reservoir or water tanker provides appropriateswitching.

Block Diagram of water tanker or reservoir with solenoid valves, Pump motor and sprinkler

S1 Water from the source

Water sprinkler

Pump motor

S2

Water flow

Fig 3.3 the block diagram of water tanker with solenoid valves, water pump and sprinkler

3.3.1 Light Intensity Detection Sensor Using LDR (light dependent resistor)

The resistance of the Light Dependent Resistor (LDR) varies according to the amount of light that falls on it. The aim of using this sensor is to stop irrigation in day time or to reducewater wastage if irrigation is in day time since there is high water evaporation and it is not recommended to irrigate in day time for plants. Using LDR to sense the existence of light whichimplies that when there is light in the irrigation land, the resistance of the LDR gets decreased in accordance with the light intensity.

3.3.2 Moisture Level Detection Using Moisture Sensor (water mark)When the moisture level of the soil gets increased the respectiveresistance value becomes decreased as result irrigation can be stopped.

3.3.3 Wind Speed Detection Using Generator Coupled Anemometer

For this project ,wind speed detector anemometer coupled withsmall a dynamo to generate DC voltage used to detremine the speedof the wind.The generator can generate different voltages inmagnitude according to the speed of the local wind and we choosethe speed that affect theSprinklers operation and we use it to set wind speed for stoppingirrigation.3.3.4 Rain Fall Detection Using Rain SensorIf there is rain, the rain sensor gets contacted since the waterconducts electricity and it is used as a switch. In this circuitwhen the rain sensor is energized at rainy time switched ON therelay open or break the irrigation system automatically as shownin fig.3.2. But when the rain stops raining, this sensor getsopened and the system can irrigate the green house if the lightintensity and wind speed are in the normal ranges and the drynessof the soil increased as shown in fig.3.2

.

3.3.5 Water Level Control Circuit for Water ReservoirThis circuit controls the level of the water in the waterreservoir (water tanker) by placing the maximum level sensor

(NC) only on the above part of the tank since the water comes into the reservoir through open channel with the help ofgravitational force. The LED represents the solenoid valve inthis circuit.

CHAPTER FOUR: RESULTS AND DISCUSSION

The automatic green house irrigation system is to irrigate thegreen on its given recommended moisture level which is obtainedfrom experimental data and by sensing the presence of lightintensity, wind speed and rainfall in normal range of values. Thethree variables which are moisture level of the soil, rainfall,local wind speed and the surrounding light intensity arecontrolled by an overall controlling circuit of automaticirrigation system controlling circuit. The watermark moisturesensor senses the moisture level of the soil, the LDR senses thelocal light intensity, the rain sensor senses the existence ofrainfall and wind blade/shaft coupled dynamo senses the speed oflocal wind. These sensing variables are interconnected to onecommon output.

CHAPTER FIVE:CONCLUSION AND RECOMMENDATION5.1 ConclusionWe conclude that in this project we have studied an automaticgreen house irrigation system by using control circuit by thehelp of sensors. The integration of different factors forefficient irrigation has been mastered during the design. Theobjective is to use sensors such as watermark moisture sensor,Light dependent resistor sensor, rain sensor and wind speedsensor as signal receivers in green house for automaticirrigation system. The results show that the sensors are able toreceive the required signals from the irrigated area and it canoperate its operation as it is required.

The results show that the system can detect moisture level of thesoil, presence of rain fall, light intensity and wind speed verywell in different electrical values.

This project can have many uses in practical fields, from savingtime to saving money and in increasing of crop production. It canbe further improved to have more decision taking capabilities byemploying varied types of sensors and thus could be used inindustries for different applications such as in prevention offire.

5.2 Recommendation

The automatic green house irrigation system still can be improvedfor future development. Some modification and renovation on thesystem have to be made in order to acquire powerful system ofautomatic green house irrigation. Therefore a list ofrecommendations is given as below:

1.The system should be tested to be practical in agriculturalsectors to assist the economic activities of the country andtherefore stakeholders such as our university and ministry ofagriculture must cooperate to see the fruit of this project.

2. The system can be used to spray the fertilizers on the greenhouse in scientific way for proper growth of the plants toincrease green house production as a whole and the system can beimproved by PLC systems and Microcontrollers. 3.The system should be installed by skillful and knowledgeablepersons in the field which have different types of soil to setthe system at the recommended values of moisture level of thesoil, local light intensity and local wind speed and it should bealso repaired by these persons when problems occurred on thesystem.

5.3 Future Work

We announce to the interested researchers who will work on thisproject to do their best on the following concepts.

The sprinkler spacing on the irrigated farm and the type ofthe sprinklers and the rating and type of pumping motor, the

capacity of the water pipes and the capacity of solenoidvalves can be specified and determined based on the need ofthe farmers who will use this technology/system.

The wind controlling circuit of the system should beimproved a lot because there will be high voltage outputfrom the dynamo when the wind speed of the local air getsincreased extremely in a sudden way.