1. TECHNICAL UNIVERSITY OF KENYA
SCHOOL OF MECHANICAL AND PROCESSING ENGINEERING
DEPARTMENT OF MECHANICAL AND MECHATRONICS ENGINEERING
TITLE: DESIGN AND FABRICATION OF SOLAR
IRRIGATION MANAGEMENT SYSTEM
by
JAPHETH LUGANJE KARISA
REG NO: 111/05619
Project report to be submitted to the department of mechanical and mechatronics
engineering in partial fulfillment for award of Degree in Mechanical Engineering of The
Technical University of Kenya
2016
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Declaration
I hereby declare that this project is my original work and has not been presented to any
institution of higher learning for examination purposes. It`s success depends entirely on my
tremendous and numerous efforts and dynamic capacity.
Signature: _________________ Date: __________________
Name: Japheth Luganje Karisa
Reg. No: 111/05619
BY SUPERVISOR
This project has been presented to TECHNICAL UNIVERSITY OF KENYA with my approval
as the supervisor of the student.
Signature: _________________ Date: ___________________
Name: Ms Sarah Ngure
Lecturer Technical University of Kenya
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Acknowledgement
I am grateful to Ms Sarah Ngure my project lecturer and my supervisor for her consistent and
valuable assistance in preparation of this project proposal. I also want to acknowledge my
brother Leonard Wanje for the assistance he offered to me in preparation of this project, fellow
students, friends, relatives who assisted me in preparation of this project.
5. v
Table of Contents
Declaration.......................................................................................................................................ii
Acknowledgement ..........................................................................................................................iii
Dedication.......................................................................................................................................iv
Abstract ........................................................................................................................................... 1
CHAPTER ONE ............................................................................................................................. 2
INTRODUCTION .......................................................................................................................... 2
1.1 Background of study ..............................................................................................................2
1.2 Problem Statement.................................................................................................................3
1.3 Objectives .............................................................................................................................4
1.4 Research questions.................................................................................................................4
1.6 Justification...........................................................................................................................4
CHAPTER TWO ............................................................................................................................ 6
2.0 Literature Review...................................................................................................................... 6
2.1 Irrigation in Kenya.................................................................................................................6
2.2 Automatic irrigation systems ..................................................................................................8
2.4 Components of the irrigation system to be designed .................................................................9
2.5 Sensors ...............................................................................................................................10
2.6 Microcontrollers ..................................................................................................................12
2.7 Actuators.............................................................................................................................13
2.8 Water pipes .........................................................................................................................15
CHAPTER THREE ...................................................................................................................... 16
3.0 Methodology And Design....................................................................................................... 16
3.2 Method ...............................................................................................................................18
3.3 Design considerations ..........................................................................................................22
3.4 Product Specifications For designed system...........................................................................24
3.5 The Arduino programme ......................................................................................................31
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3.6 Test and experimentation................................................................................................. 34
3.6.1 Experiment setup ..............................................................................................................34
CHAPTER FOUR............................................................................................................................38
4.0 RESULTS AND DISCUSSION...................................................................................................38
4.3 Limitation of the system.......................................................................................................40
4.4 Challenges Faced.................................................................................................................40
4.5 Facilities that were used.......................................................................................................40
CHAPTER FIVE .......................................................................................................................... 41
CONCLUSION AND DISCUSION............................................................................................. 41
5.1 Conclusion ..........................................................................................................................41
5.2 Recommendation.................................................................................................................41
WORKING SCHEDULE ............................................................................................................. 42
References..................................................................................................................................... 43
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List of Figures
Figure 2.1 Galana Irrigation ................................................................................................................6
Figure 2.2 Mwea flood irrigation .........................................................................................................7
Figure 2.3 Block representation of irrigation system using GPRS module...............................................8
Figure 2.4 Block representation of Automatic Irrigation system using timers..........................................9
Figure 2.5 reciprocating pumps..........................................................................................................14
Figure 2.6 rotary pumps ....................................................................................................................15
Figure 3.1 layout of the irrigation system .............................................. Error! Bookmark not defined.
Figure 3.2 illustrating the layout of the pump and pipes.......................... Error! Bookmark not defined.
Figure 3.3 Schematic diagram of the designed irrigation system ............. Error! Bookmark not defined.
Figure 3.4 seaflo mini pump.................................................................Error! Bookmark not defined.
Figure 3.5 arduino microcontroller........................................................ Error! Bookmark not defined.
Figure 3.6 Relay switch........................................................................ Error! Bookmark not defined.
Figure 3.7 LCD display........................................................................ Error! Bookmark not defined.
Figure 3.8 Schematic diagram of the connection ....................................Error! Bookmark not defined.
Figure 3.9 image showing the assmbled components.............................. Error! Bookmark not defined.
Figure 3.10 image of the circuit board................................................... Error! Bookmark not defined.
Figure 3.11 image of the valve and moisture sensor in the soil................ Error! Bookmark not defined.
List of Tables
Table 3.1 materials used to make the irrigation system..............................Error! Bookmark not defined.
Table 3.2 Display Specifications of the microcontroller.............................Error! Bookmark not defined.
Table 3.3 LCD Display Specifications .....................................................Error! Bookmark not defined.
Table 3.4 parts of the assembled irrigation system....................................Error! Bookmark not defined.
Table 3.5 parts of the control unit ............................................................Error! Bookmark not defined.
Table 3.6 the irrigation parts..................................................................Error! Bookmark not defined.6
Table 4.1 power consumption..................................................................Error! Bookmark not defined.
Table 4.2 pump results ......................................................................................................................39
Table 5.1 working Schedule ..................................................................Error! Bookmark not defined.2
8. Abstract
Some of the current problems facing Kenya are; environmental pollution, raising fuel prices and
food shortage. Pollution of the environment is mainly brought about by use of fossil fuels that
pollute the air by releasing carbon monoxide, unburnt hydrocarbons and nitrogen oxides among
others.
Food shortage is a world-wide problem that also affects Kenya. Among the solution proposed to
solve this problem is putting dry lands under irrigation in order to increase food production.
Others try to use economical methods of agriculture such as mulching, reduction of the present
rate of degradation and loss of productive farmland due to erosion, salinization, waterlogging,
and nutrient depletion: Technologies for these purposes are available, but are little used because
of the expense.
Most people practicing irrigation use pumps to pump water from the source to the cultivated
lands. Others create sills and dykes that can trap stream water and then redirected to allow water
flood over the land under cultivation. Those using pumps use diesel and petrol as a source of
power for the pump. The price of petroleum products keep on fluctuating and becoming
expensive day by day due to political events, economic growth which causes excess supply
leading to shortage, fluctuation in currency rates among others.
The objectives of this project, is to solve such problems. There was need to come up with better
irrigation methods which are economical and environmental friendly. A solution to this was
found to be an automatic solar irrigation management system.
The system makes use of sensors and mechanical actuators to control the whole irrigation
process. After designing the control system the design was transformed in to a real product.
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CHAPTER ONE
INTRODUCTION
1.1 Background of study
Irrigation is the artificial application of water to the land or soil. People around the world have
been struggling to end the hunger crisis globally. Most of them have been doing so by practicing
agricultural activities. Different technologies have been coming up to improve on the agriculture
productivity. One of the areas is by practicing smart farming and improving on agricultural
irrigation activities.
Food security is one of the major problems in most developing countries. In Kenya half of its
population cannot practice agriculture because 60% of Kenya is either an arid or a semiarid. This
reduces agricultural activities in Kenya and therefore there is need to convert these lands to be
productive is through irrigation.
15 years ago the government of Kenya set its primary development blue print that is the vision
2030. To establish a good foundation towards the achievement of vision 2030 the government
adopted the millennium development goals established by the United Nations. One of the
development goals was to eradicate extreme poverty and hunger. The government has been
trying its best to eradicate poverty and hunger but very little has been done. Currently the United
Nations came up with the sustainable development goals, among them was to end poverty in all
its forms everywhere.
Agriculture is a source of income to more than 20% of Kenyans. However a large percentage of
Kenyans live in areas where there is unpredictable low rainfall or no rainfall at all a good
example being Chakama, in Magarini constituency situated along river Galana at an altitude of
17m above the sea level and an average temperature of 31oC. The place is an arid area and rarely
produces food due to the little or no rainfall at all. The people around decided to use the water
from river Galana to irrigate their crops so as to improve on food security. To make their work
easier they decided to buy a diesel water pump that could be used.
Most irrigation pumps run on diesel, petrol or electricity and are very expensive to operate due to
the high cost of petroleum products and hydro-electric power.
The project collapsed and hunger is still the major problem in the area. The major challenges the
farmers faced was that they could not afford to buy diesel every time they wanted to irrigate, the
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cost of labor was very high as they used to employ people to help them irrigate their lands and
fluctuations in water level in the river made them not irrigate their lands when the water level
was very low.
Solar energy is the most abundant source of energy in the world. It is an alternative source of
energy and is not only an answer to today’s energy crisis but also an environmental friendly form
of energy that helps in environmental conservation. Photovoltaic generation is an efficient
approach for using the solar energy. Solar panels (an array of photovoltaic cells) are nowadays
extensively used for running street lights, for powering water heaters and to meet domestic loads.
The cost of solar panels has been constantly decreasing which encourages its usage in various
sectors. In this project solar power is used in irrigation systems for farming. Solar powered
irrigation system can be a suitable alternative for farmers in the present state of energy crisis in
Kenya and the whole world. This is a green way for energy production which provides free
energy once an initial investment is made.
1.2 Problem Statement
In an effort to convert arid and dry areas to fertile lands most people tend to use irrigational
activities to improve in agricultural production and mostly they make use of diesel pumps.
Diesel pumps also tend to pollute the environment through emission of Particulate matter (PM),
Carbon monoxide (CO), Nitrogen oxides (NOx) and Hydrocarbons (HC) to the air. This
increases the greenhouse gases, leading to global warming, affect the health of living organisms
due to respiratory diseases caused by inhaling of these toxic gases and formation of acid rain.
Irrigating a large piece of land requires a lot of labor to control the irrigation lines. Most farmers
try to reduce these expenses by practicing flood irrigation. This type of irrigation tends to flood
the land making it unsuitable for plant growth thus reducing productivity. The farmers used to
employ two laborers who used to be paid after every successful irrigation. They used to incur
fuel expenses which kept on fluctuating day by day. Bearing in mind these people are very poor
that was a very big problem to them.
Due to these problems there is a need to come up with a better irrigation system that conserves
the environment and pocket friendly.
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1.3 Objectives
1.3.1 Main Objective
To design, fabricate, assemble and test a solar powered automatic irrigation management system
1.3.2 Specific Objectives
1. To design an irrigation system that is automatic and environmental friendly
2. To assemble and test the parts of the irrigation system
3. To design a control unit for the irrigation system
4. To test the automatic irrigation system
1.4 Researchquestions.
The research questions are:
a. What is an irrigation system?
b. How can the irrigation system run on solar power?
c. How can a microcontroller be used to control an irrigation system?
d. How can the material be used suitable for all weather conditions?
e. How can an automatic solar irrigation system be economical and environmental friendly?
f. What is environmental pollution and its conservation measures?
1.6 Justification
Based on the problems stated above, hunger can only be eradicated through increase of
agricultural activities. The dry lands can be converted in to fertile wet land only through
irrigation.
Irrigating a large piece of land requires a pump. To cut the cost incurred to buy fuel for the
irrigation pumps then solar energy can be used as it is cheap, renewable and readily available.
To reduce pollution caused by burning of fuel used to run the pumps, solar energy which is clean
and green can be used.
Cost of labor incurred through employment of laborers to irrigate the lands can be reduced by
having an automatic irrigation system that can run on its on without involvement of many hands.
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To manage the water used for irrigation well correct amount of water should be distributed on
the land evenly and on the places that have inadequate water.
To solve all these problems a solar powered automatic irrigation management system needs
to be developed.
13. 6
CHAPTER TWO
2.0 Literature Review
Irrigation is the artificial application of water to the land or soil. There are various irrigation
practices around the world. These include surface irrigation, drip irrigation and overhead
irrigation. The irrigation methods keep on improving day by day in an effort to make good
utilization of water and conserve the environment.
2.1 Irrigation in Kenya
Smallholder irrigation schemes Geography and weather patterns make irrigated agriculture in
Kenya indispensable since only about 20 per cent of the country has a high or medium potential
for agricultural production. The estimated potential area for irrigation and drainage in Kenya is
about 540,000 hectares (3,240km2) and 600,000 hectares (3,600km2) respectively. (Philip
Mwakio, 2016)
Figure 2.1 Galana Irrigation
The major irrigation schemes in Kenya include: Bura irrigation scheme, the bunyala I.S, Mwea
Tebere I.S, Perkera I.S, Tana-Hola I.S, west Kano I.S, and the recent Galana Kulalo irrigation
scheme.
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Figure 2.2 Mwea flood irrigation
Most irrigation schemes practice flood irrigation. They create sills and dykes that can be tap
water across a stream then the water can be redirected to allow water flood over the land under
cultivation. This is mostly practiced in the rice growing areas like Mwea and Tana. Another
method mostly practiced is basin irrigation which is almost similar to the flood irrigation. In this
water is directed from the source into shallow basins using canals. The water flows under the
force of gravity.
Another irrigation method used in Kenya is drip irrigation. This is the method of watering plants
with very small outlets that let out water at a time. It consists of pipes with very small outlets that
allow water drops out wetting the soil around the plants roots. It is a good method as it helps in
water conservation since no water is wasted as run off.
2.1.1 Irrigation Challenges in Kenya
1. Poor farm management of irrigation
2. Water logging due to poor irrigation methods
3. Declining soil fertility and soil erosion in areas where flood irrigation is practiced
4. Growing water scarcity due to fluctuation in water levels in water bodies
5. Land degradation and climate change (Gerald Andae, 2016)
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2.2 Automatic irrigation systems
An automated irrigation system refers to the operation of the system with no or just a minimum
of manual intervention beside the surveillance. Almost every system (drip, sprinkler, surface)
can be automated with help of timers, sensors, computers or mechanical appliances. 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. So many people around the world have been working
hard to make a very simple automatic irrigation system and improve its efficiency.
Joaquín Gutiérrez, Juan Francisco Villa-Medina, Alejandra Nieto-Garibay, and Miguel Ángel
Porta-Gándara from Mexico came up with an automated irrigation system using a wireless
sensor network and GPRS Module. In their system a computer was required and also a GPRS
device. The system was powered by photovoltaic panels and had a duplex communication link
based on a cellular-Internet interface that allowed for data inspection and irrigation scheduling to
be programmed through a web page. This made the project more expensive and only used by
farmers with a good computer knowledge. The automated system was tested in a sage crop field
for 136 days and water savings of up to 90% compared with traditional irrigation practices of the
agricultural zone were achieved. They also used wireless electromagnetic sensor units that could
not accurately detect the soil moisture content. [Joaquín, Villa-Medina, Nieto-Garibay, & Porta-
Gándara]
Figure 2.3 Block representation of irrigation system using GPRS module
Mehamed Ahmed Abdurrahman, Gebremedhn Mehari Gebru & Tsigabu Teame Bezabih from
Mekelle Mekelle University in Ethiopia developed an automatic irrigation system which had no
16. 9
soil moisture sensors. Instead they control the valves for the sprinklers using timers. This worked
on trial and error as the correct amount of water to be irrigated could not be established. It also
involve many staffs who used to check on the dryness of the soil so as to start the irrigation
system. [Mehamed, Mehari & Bezabih, 2015]
Figure 2.4 Block representation of Automatic Irrigation system using timers
2.4 Components of the irrigation systemto be designed
A sensor is a device that detects and responds to some type of input from the physical
environment. Sensors are used worldwide and their usage has been increasing day by day mostly
In the atomization of systems and machines.
An actuator is a type of transducer that is responsible for moving or controlling a mechanism or
system after receiving a signal from a control unit. It is operated by a source of energy, typically
electric current, hydraulic fluid pressure, or pneumatic pressure, and converts that energy into
motion.
A microcontroller is a computer present in a single integrated circuit which is dedicated to
perform one task and execute one specific application. It contains memory, programmable
input/output peripherals as well a processor. Microcontrollers are mostly designed for embedded
17. 10
applications and are heavily used in automatically controlled electronic devices such as
cellphones, cameras, microwave ovens, washing machines, etc.
2.5 Sensors
2.5.1 Soil moisture sensors
2.5.1.1Watermark soil moisture sensor
This type of moisture sensor is used to measure the moisture content of soil. This is achieved by
placing the sensor in the upper and lower threshold of the root zone. The sensor then reads the
moisture from 0 centibars for saturated and 200 centibars for dry soil. [Fraden, 2014]
Advantages
a. Watermark is a cheap moisture sensor
b. It is easy to use by different people
Disadvantages
It is difficult to find it in the local market.
2.5.1.2 WaterScout SMEC 300
This sensor measures the soil moisture, salts and the soil temperature. The sensor is placed on the
effective root zone in order to measure the above named parameters.
Advantages
a. This sensor can measure three parameters including soil moisture, soil temperature and
amount of salts in the soil.
b. This sensor is easy to use
Disadvantages
It is an expensive sensor
2.5.1.3 Gravimetric Weight method
This method is done by weighing the soil under consideration. The sample is then dried in an
oven and then weighed again. The weight difference in this case then corresponds to the mass of
water in the soil. The results obtained through this process are then used to determine whether
the plant requires water or not.
In this method, care should be taken that the temperatures do not go too high such that it can
destroy other organisms in the soil. [Fraden, 2014]
Advantages
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a. Low cost method
b. It does not require any special skills.
Disadvantages
a. Heating is required which brings out a hectic process which is time consuming.
b. It has a procedure which has to be followed to the latter.
c. The process has to be repeated periodically which becomes unfavorable for irrigation
monitoring.
2.5.1.4 Tensiometers
This sensing method uses an airtight water-filled tube with a porous ceramic tip which is placed
in the soil and a vacuum case that protrudes on the ground. It measures the water tension and
displays it on the gauge.
Tensiometers measure the moisture content only at the area where the tip is located.
In order to effectively use these tensiometers they should be placed at the center of the effective
root zone and another one below the effective root zone. In this way the one above is used to
start irrigating and the one below to stop irrigation.
The readings of the tensiometers are done in millibars where zero reading show saturated soil
and higher reading shows drier soil.
Advantages
a. Easy to place and mount.
b. The readings can be connected to an external monitoring system.
Disadvantages
a. They can require re-installation when soil gets too dry.
b. They require time to time servicing which is hectic.
c. They are highly unreliable and problematic since they require a vacuum.
d. Their success highly depends on the initial installation.
2.5.1.5 Probes
To monitor the soil moisture content, probes are used. The probes are placed at strategic
positions in the. When the soil is well watered, a connection is formed between the probes and
the circuit is completed as water acts as a good conductor in the presence of mineral salts in the
soil. The when the soil is watered well, the resistance is reduced significantly to allow for current
to flow. When the soil is dry, there is no conduction and this causes the valve to open and the soil
is watered. These are the sensors that I will use in my irrigation system. [Fraden, 2014]
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Advantages
Cheap to implement and can be done by anybody.
Disadvantages
a. It doesn’t give the exact water content of the soil.
b. To monitor all the areas in the greenhouse, there is the need of many probes to be placed
at different areas
2.6 Microcontrollers
2.6.1 Classification According to Number of Bits
The bits in microcontroller are 8-bits, 16-bits and 32-bits microcontroller.
In 8-bit microcontroller, the point when the internal bus is 8-bit then the ALU performs the
arithmetic and logic operations. The examples of 8-bit microcontrollers are Intel 8031/8051,
PIC1x and Motorola MC68HC11 families.
The 16-bit microcontroller performs greater precision and performance as compared to 8-bit. A
longer timer most extreme worth can likely prove to be useful in certain applications and circuits.
It can automatically operate on two 16 bit numbers. Some examples of 16-bit microcontroller are
16-bit MCUs are extended 8051XA, PIC2x, Intel 8096 and Motorola MC68HC12 families.
The 32-bit microcontroller uses the 32-bit instructions to perform the arithmetic and logic
operations. These are used in automatically controlled devices including implantable medical
devices, engine control systems, office machines, appliances and other types of embedded
systems. Some examples are Intel/Atmel 251 family, PIC3x. [Lucio 2011]
2.6.2 Classification According to Memory Architecture
Memory architecture of microcontroller are two types, they are namely:
a. Harvard memory architecture microcontroller
b. Princeton memory architecture microcontroller
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Harvard Memory Architecture Microcontroller: The point when a microcontroller unit has a
dissimilar memory address space for the program and data memory, the microcontroller has
Harvard memory architecture in the processor.
Princeton Memory Architecture Microcontroller: The point when a microcontroller has a
common memory address for the program memory and data memory, the microcontroller has
Princeton memory architecture in the processor.
2.7 Actuators
2.7.1 Solenoid Valves
The solenoid valve consists of a solenoid coil and mechanical parts that regulate the size of an
opening. An electric current flow through an electrical conductor, the wire generates a magnetic
field which is then amplified by focusing the electrical conductors in the form of a coil. The
classification of solenoid valves is as below:
2.7.1.2 According to resting state
Normally closed solenoid valve
The resting state depends on the flow of current across the solenoid. When no current is flowing
then the solenoid remains in resting position. As a current begins to flow then a piston in the
valve moves to open the inlets and outlets.
Normally open solenoid valve
In this type of solenoid the fluid flows when the solenoid is in its resting position. This means at
this time there is no current flowing.
2.7.1.3 According to number of ports
2 Way solenoid valves.
These solenoid valves have two ports an inlet and an outlet with only one opening allowing fluid
control.
3 - Way solenoid valves.
They contain three ports an inlet, an outlet and an exhaust with two openings allowing for fluid
control.
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2.7.1.4 According to operating current.
Direct Current solenoid
The current that flows through this kind of solenoid is a direct current. As a result they are
quieter, wear less at the solenoid core, have high solenoid holding force, they have same holding
and picking power.
Alternating current solenoid
The current that flows through this kind of solenoid is an alternating current. They produce some
noise; if the solenoid is jammed there is a higher risk of solenoid coil burn out. The advantage of
this solenoid is the feature of fast switching.
2.7.2 Pumps
Pumps are devices which convert mechanical energy into hydraulic energy. The pump is used to
impart motion to the liquid. It provides the force required to transmit power and motion. The
pump does not produce power. It only produces fluid flow.
Pumps can be classified based on their design, this can be:
1. Rotary pumps
2. Reciprocating pumps
Figure 2.5 reciprocating pumps
22. 15
Reciprocating pumps operate by creating a vacuum which causes the inlet valve to open to allow
the water into the cylinder. The water is then compressed where the volume is redcued and
pressure increasing thus opening the outlet valve allowing water out. Examples of reciprocating
pumps include piston pumps and diaphragm pumps.
Rotary pumps consist of a housing, an eccentrically installed rotor, vanes that move radially
under centrifugal and resilient forces and the inlet and outlet. The working chamber is located
inside the housing and is restricted by the stator, rotor and the vanes. The eccentrically installed
rotor and vanes divide the working chamber into two separate compartments with variable
volumes. As the rotor turns, gas flows into the enlarging suction chamber until it is sealed off by
the second vane. The enclosed gas is then compressed until the outlet valve opens against
atmospheric pressure. Example of rotary pumps include screw pumps, gear pumps, vane pumps,
centrifugal pumps and lobe pumps.
Figure 2.6 rotary pumps
2.8 Water pipes
There are different types of pipes that can be used to transmit water from one place to another,
these include:
23. 16
Steel Pipe, Cast-Iron Pipe, Asbestos-Cement Pipe, Poly Vinyl Chloride Pipe and Poly Ethylene
Pipe
CHAPTER THREE
3.0 Methodology And Design
The solar powered automatic irrigation management system comprised of the following
equipment and materials:
3.1 Experimental set up
3.1.1 Equipment of the automatic irrigation management system
1. Source of power
2. Source of water
3. Storage of water
4. Control unit of the system
5. 12v water pump
6. Solenoid valve
3.1.2 Tools used to make the systemwere:
1. Pliers
2. Tester (screwdriver cum testing circuit)
3. Solder
24. 17
3.1.3 Materials used to make the systemwere:
Table 3. 1 materials used to make the irrigation system
Material Size Quantity
DC battery
12v 1
Bread board
Small 1
Bread board wires
Standard 10m
Soil moisture sensor
5V 1
Water level sensor
5V 1
A microcontroller
12V 1
DC water pump
12V 1
Buckets
10litres 2
Solenoid valve
12V 1
Long thread nipples
½ inch 2
LCD display
16 x 2 1
Flex pipes
½ inch 10
Relays
- 2
Connectors
- 8
Back nuts
½ inch 4
T-junctions with stoppers
½ inch 2
Elbow Junction
½ inch 2
Thread tapes
10meters 1
25. 18
3.2 Method
3.2.1 Description of the system
a. Power
The source of power for the whole system is solar power. The solar power reaches a 12V 7Ah
battery that stores the energy. The system works effectively near a source of water, e.g a
borehole, a river or a lake.
b. Pump
The pump used was 12V vanes pump that. It pumped water from the source to a storage tank.
c. Source and Storage Tank
The source was a 10 liter plastic bucket which contained water. The storage tank was a 10
liters bucket and had a water level sensor which was set to detect water at certain levels.
When the water in the storage tank reached the required level the pump stops pumping.
Whenever water dropped below the set level the water level sensor actuated the pump which
started the pumping process again.
d. Irrigation
Irrigation pipes were connected from the tank to sprinklers in the cultivated land. Each sprinkler
had a valve. Soil moisture sensors were placed at certain levels in the soil depending on the crop
planted. Whenever the soil got dry below the set value, the sensors actuated the valves which
opened and the land was irrigated by the sprinklers. Whenever the soil gets enough moisture the
sensors actuated the sprinkler valves which close and stop the irrigation process. The layout and
block diagram of the system is as shown on fig 3.1.1 and fig 3.1.3 below respectively
e. LCD display Screen
The system has and LCD display screen, it displays the various commands given out by the
microcontroller, example “PUMP ON” and “TANK EMPTY”
28. 21
3.2.2 The design of the system was as follows:
a. One bucket acted as a storage tank while the other was the source of water
b. A program was designed to control the soil moisture sensor and the water level sensor
c. The program was fed into an Arduino nano microcontroller
WATER LEVEL
SENSOR ARDUINO
MICROCONTROLLER
SOLENOID
VALVES
STORAGE TANK
SOLAR
POWERED
PUMP
SOIL
MOISTURE
SENSOR
GARDEN SPRINKLERS
12V DC POWER
SUPPLY
RIVER
WATER FROM STORAGE TANK
WATER FROM THE SOURCE
INPUT CURRENT
INPUT SIGNAL
OUTPUT SIGNAL
Figure 3.3 Schematic diagram of the designed irrigation system
29. 22
d. All the connecting wires were connected to a bread board which provided an easier
method of assembling and disassembling the system thus increasing portability
e. The water level sensor (ultrasonic sensor) was placed on top of the bucket (storage tank)
and then connected to the microcontroller
f. The LCD was connected to the microcontroller using jumper wires
g. The soil moisture sensor was placed in the soil and then connected to the microcontroller
h. Relays were used to open and close the pump and the solenoid valve depending on the
status
i. For the storage tank two holes were made (for the inlet and outlet) and water tight back
nuts were used to ensure that there was no leakage
j. Flex pipes (half inch) inter-connected by nipples were used to transmit water from the
source to the storage tank via the pump and from the storage tank to the soil via the
solenoid valve
k. The pump and the solenoid valves were connected to the relays which controlled the
switching on or off of the pump depending on the status output of the microcontroller
l. The source of power for the whole system was a 12v rechargeable DC battery
3.3 Designconsiderations
3.3.1 Designconsideration of the Pump
In order to select a suitable pump it is of importance to know the power output of the pump, the
pressure head, frictional losses incurred, the type of current and the voltage rating. Discharge
Head: is the vertical distance between the pump datum point and the liquid surface in the
receiving tank. The pump datum is at the center line for horizontal pumps and at the entrance eye
of the impeller for vertical pumps.
30. 23
Suction Head: if the water to be pumped has its surface ABOVE the center of the pump, then this
relationship is called a suction head. More technically, it is the positive vertical distance between
the pump datum and the liquid surface in the suction well. (Wright, 2016)
Static Head: Static head is the distance that the water is to be lifted.
Static Head = Discharge Head - Suction Head
Friction Head: is the head necessary to overcome the friction in the pipes, fittings, valves,
elbows, etc.
Total Dynamic Head (TDH), is the sum of the Static Head and the Friction Head. The Total
Head, or TDH, is the value used in the horsepower calculations.
The power of the pump can be obtained by:
P = Qhρg ……………................................................... 3.1 [Dr sleigh, 2001]
Where Qis the pump flow rate, h is the total dynamic head and ρ is the density of water.
The flow rate of the pump used was given as 750 gallons per hour.
This can be converted into m3/s as follows;
1 imperial gallon= 0.00454609 m3
1 hour = 3600seconds
Therefore 750gallons per hour =
750 ×0.00454609
3600
= 9.471 x 10-4 m3/s
Q= AV ………………………………………………………………….3.2 [Dr sleigh, 2001]
Where A is the area of the pipe and v is the velocity of the water
The velocity of the water can be obtained since the flow rate Q is known and the area A can be
calculated;
The diameter, d of the pipes is 0.5 inch, which is equal to 25.4 x 0.5= 12.7mm
31. 24
Cross-sectional area of the pipe is;
π
d2
4
= π ×
12.72
× 10−6
4
= 1.267 × 10−4
m2
v =
Q
A
=
9.471 × 10−4
1.267 × 10−4
= 7.477 m/s
TDH = z + hf ………………………………………………………………….3.3
TDH is the total dynamic head
Z is the elevated height which was 1.5m (static head)
hf Frictional head loss:
hf =
4fLV2
d2g
……………………………………………………………………3.4 [Dr sleigh, 2001]
Where:
f- is resistance coefficient = 0.0015
L is the Length of the pipe = 1.5m
d is the diameter of the pipe = 0.0127m
hf =
4×0.0015×1.5×7.4772
0.0127 ×2×9.81
= 0.202m
Thus TDH = 1.5+0.202= 1.702m
Calculate power of the pump, P = Qhρg = 15.81Watts
3.4 Product Specifications For designed system
3.4.1 Water Pump (Liquid Pump - 750gph/2850lph (12v)
This fluid pump moves 750 gallons per hour. The SEAFLO mini water pump has a heavy duty
12V, 1.5Amp motor and a tough thermoplastic body. Features:
32. 25
The maximum delivery head was 3.8 metres (height of vertical water flow up pipe). The pump is
a vane pump and an outlet of ½ inch. The pump motor is of permanent magnet type and rated for
12V DC power input from either a direct source or photovoltaic modules. [Nerokascoke, 2016]
Figure 3.4 seaflo mini pump
For real farm implementation SHURflo DC Booster pumps can be used. SHURflo DC Booster
pumps are designed for reliable general duty water transfer applications, their unique design
providing easy maintenance and high efficiencies. They are of positive displacement three-
chamber diaphragm design with built-in check valve allowing for self-priming operation and the
ability to run dry without damage. All pumps also incorporate a pressure switch providing the
facility for automatic on-demand installations. Also, for added reliability available extras include
a twist-on line-strainer and a heat sink recommended for continuous operation in hot conditions.
Principal pump components are manufactured from polypropylene with santoprene used for the
diaphragm and santoprene (model 2088), EPDM (model 8000) or Viton (model 8030) for the
valves.
3.4.2 Water level sensor(HC-SR04)
The HC-SR04 ultrasonic sensor uses sound to determine distance to an object like bats or
dolphins do. It offers excellent range accuracy and stable readings in an easy-to-use package. It
operation is not affected by sunlight or black material like Sharp rangefinders are (although
acoustically soft materials like cloth can be difficult to detect). [Nerokascoke, 2016]
33. 26
Power Supply: 5 V DC
Ranging Distance : 2cm – 500 cm
3.4.3 Moisture sensor
It can be used to detect soil moisture when making an automatic plant watering system. It
consists of the module, detection probe and connecting wires. Digital and analog outputs and
has an adjustable potentiometer to modify the sensitivity to humidity and moisture. When the
soil moisture is less that a set threshold value the digital output increases and when the moisture
exceeds the threshold set the digital output will decrease. [Nerokascoke, 2016]
a. Operating voltage: 3.3 to 5V
b. Probe size 60mm x 20mm
3.4.4 Microcontroller
The Arduino Duemilanove (“2009″) is a microcontroller board based on
the ATmega168 or ATmega328. It has 14 digital input/output pins (of which 6 can be used as
PWM outputs), 6 analog inputs, a 16 MHz crystal oscillator, a USB connection, a power jack, an
ICSP header, and a reset button. It contains everything needed to support the microcontroller;
simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or
battery to get started.
Table 3. 2 Specifications of the Microntroller
Part Specifications
Microcontroller ATmega168
Operating Voltage 5V
Input Voltage (recommended) 7-12V
Digital I/O Pins 14
Analog Input Pins 6
DC Current per I/O Pin 40 mA
Flash Memory 16 KB (ATmega168) or 32 KB (ATmega328)
Clock Speed 16MHz
34. 27
Figure 3.5 arduino microcontroller
a. Power
The Arduino Duemilanove can be powered via the USB connection or with an external power
supply. The board can operate on an external supply of 6 to 20 volts.
The power pins are as follows:
i. VIN. The input voltage to the Arduino board when it's using an external power.
ii. 5V. The regulated power supply used to power the microcontroller and other components
on the board. This can be supplied by USB or another regulated 5V supply.
iii. GND. Ground pins.
b. Memory
The ATmega168 has 16 KB of flash memory for storing code. The ATmega328 has 32 KB.
c. Input and Output
Each of the 14 digital pins on the Duemilanove can be used as an input or output, using
pinMode(), digitalWrite(), and digitalRead() functions. They operate at 5 volts.
The Duemilanove has 6 analog.
35. 28
d. Programming
The Arduino Duemilanove can be programmed with the Arduino software.
3.4.5 Relay
Relays are switches that open and close circuits electromechanically or electronically. Relays
control one electrical circuit by opening and closing contacts in another circuit. It is used to
operate the pump and the solenoid valve.
Figure3.6 Relay switch
3.4.6 LCD Display
LCD (Liquid Crystal Display) screen is an electronic display module and has a wide range of
applications. LCDs are economical; easily programmable; have no limitation of displaying
special & even custom characters (unlike in seven segments).
A 16x2 LCD means it can display 16 characters per line and there are 2 such lines. This LCD has
two registers, namely, Command and Data.
The command register stores the command instructions given to the LCD. A command is an
instruction given to LCD to do a predefined task like initializing it, clearing its screen, setting the
cursor position, controlling display etc. The data register stores the data to be displayed on the
LCD. The data is the value of the character to be displayed on the LCD.
a. Pin Description:
36. 29
Figure 3.7 LCD display
Table 3. 3 LCD Display Specifications
Pin No Function Name
1 Ground (0V) Ground
2 Supply voltage; 5V (4.7V – 5.3V) Vcc
3 Contrast adjustment; through a variable resistor VEE
4 Selects command register when low; and data register when high Register Select
5 Low to write to the register; High to read from the register Read/write
6 Sends data to data pins when a high to low pulse is given Enable
7
data pins
DB0
8 DB1
9 DB2
10 DB3
11 DB4
12 DB5
13 DB6
14 DB7
15 Backlight VCC (5V) Led+
16 Backlight Ground (0V) Led-
37. 30
b. How to connect the LCD display screen
The LCD was connected as follows:
1. LCD RS pin to digital pin 12
2. LCD Enable pin to digital pin 11
3. LCD D4 pin to digital pin 10
4. LCD D5 pin to digital pin 9
5. LCD D6 pin to digital pin 8
6. LCD D7 pin to digital pin 5
7. LCD R/W pin to ground
8. LCD VSS pin to ground
9. LCD VCC pin to 5V
Figure 3.8 Schematic diagram of the connection
38. 31
3.5 The Arduino programme
This is the programme that was used to run the system
#include <LiquidCrystal.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 10, 9, 8, 5);
#define echoPin 6// Echo Pin
#define trigPin 7// Trigger Pin
int ld = 13;
int pumpON = 3;
int valve = 4;
int moisturelevel;
long duration, distance; // Duration used to calculate distance
long tanklevel;
void setup() {
Serial.begin (9600);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
pinMode(pumpON,OUTPUT);
pinMode(ld,OUTPUT);
pinMode(valve, OUTPUT);
digitalWrite(valve, HIGH);
// pinMode(pumpOFF,OUTPUT);
lcd.begin(16, 2);
lcd.setCursor(0, 0);
lcd.print("JAPHETH KARISA");
lcd.setCursor(0, 1);
lcd.print("FINAL YR PROJECT");
delay(4000);
}
void loop()
{
39. 32
moisturelevel = analogRead(0);
if (moisturelevel < 200) {
digitalWrite(valve, LOW);
lcd.setCursor(8, 1);
lcd.print("VALVEOFF");
}
else{
digitalWrite(valve, HIGH);
lcd.setCursor(9, 1);
lcd.print("VALVEON");
}
/* The following trigPin/echoPin cycle is used to determine the
distance of the nearest object by bouncing soundwaves off of it. */
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
//Calculate the distance (in cm) based on the speed of sound.
distance = duration/58.2;
if(distance>50)
{
distance=50;
float dif = 50 - distance;
double fract = dif/50.0;
tanklevel = fract*100;
lcd.setCursor(0,0);
lcd.print("TANK LEVEL:");
lcd.setCursor(12,0);
lcd.print(tanklevel,DEC);
41. 34
3.6 Test and experimentation
3.6.1 Experiment setup
Experiment was conducted on the fabricated irrigation management system. The fabricated
system is as shown below.
Figure 3.97 image showing the assmbled components
1
4
5
6
7
3
2
42. 35
Table 3. 4 parts of the assembled irrigation system
Label Component
1 Storage Bucket
2 12V DC Battery
3 Control Unit
4 Long-thread nipple
5 Flex Pipes
6 Solenoid Valves
7 Pump in Water
The bucket for the source of water was filled with water 12 liters. The pump was submerged into
the source of water and it was connected to a 12v dc source of power through the relays.
Figure 3.108 image of the circuit board
2
1
3
2
43. 36
Table 3. 5 parts of the control unit
Label Component
1 Relay
2 Breadboard
3 Microcontroller
4 LCD display
The storage bucket was connected to the source of water using flex pipe through the pump. The
storage tank was fitted with a solenoid valve at the outlet which was connected to flex pipes
outlet that were used to irrigate the soil.
Figure 3.119 image of the valve and moisture sensor in the soil
Table 3. 6 The irrigation parts
Label Component
1 Moisture sensor
2 Solenoid valve
3 Soil
The solenoid valve was connected to the relays on the bread board. A water level sensor
(ultrasonic sensor) was place on top of the storage bucket and connected to the microcontroller.
The soil used was sand-loam soil. The soil moisture sensor probes were dipped into the soil and
1
3
2
44. 37
connected to the microcontroller. The microcontroller was fed with a program that was used to
monitor and control the system. The microcontroller was connected to a power source which was
12 V dc.
45. 38
CHAPTER FOUR
4.0 RESULTS AND DISCUSSION
The automatic irrigation system has a pump that pumps water from a source to a storage tank. In
the tank there is a water level sensor that monitors the variation in water level. When the water
reaches the highest set level an analog signal is sent to the microcontroller and the
microcontroller sends a digital signal to the relay which eventually switches off the pump. The
water in the storage tank is directed to the irrigated soil. When water in the soil reaches the set
level the soil moisture sensor in the soil sends and analog signal to the microcontroller, the
microcontroller sends a signal to the relay connected to the valve and the relay closes the valve.
When the switch was turned on:
a. The microcontroller output voltage of 5v was able to power the ultrasonic sensor and the
soil moisture sensor..
b. The pump turned on to pump water from the source to the storage bucket whenever water
in the storage bucket fell below the set level
c. The solenoid valve opened to allow flow of water to the soil and was closed when the soil
became wet enough.
d. The microcontroller received signal from the sensors and actuated the relays which
opened and closed to turn on or off the pump and open or close the valve.
4.1 Power consumption results
Table 4. 1 Power consumption
Component voltage input
/output (V)
Current (A) Power (W) Did it work as per
expectations?
Soil moisture sensor 5 0.007 0.035 YES
Water Level Sensor 5 0.002 0.01 YES
Relay 5 0.04 0.02 YES
Solenoid valve 12 0.32 3.84 YES
Pump 12 1.5 18 YES
Microcontroller 12 0.6 7.2 YES
46. 39
4.1.1 Analysis of the above results
From chapter 3.3 the calculated power of the pump was found to be 15.81W. From the above
data the power of the pump can be calculated as
P = VI………………………………………………………………………………Equation 4. 1
= 12 × 1.5
=18W
The difference in the two results i.e
18 – 15.81 = 2.19W
This difference is power loss is due to bends in piping, hysteresis and frictional loss of the motor
and eddy currents of the motor.
4.2 Pumping results
Table 4. 2 Pump Results
Test Time Volume of displaced water
1 10seconds 8liters
2 12 seconds 8 liters
3 11 seconds 8 liters
From the above data the flow rate of the water can be calculated.
𝐟𝐥𝐨𝐰𝐫𝐚𝐭𝐞 =
𝐯𝐨𝐥𝐮𝐦𝐞
𝐭𝐢𝐦𝐞
[Dr sleigh, 2001]
For result 1 flowrate, Q1 =
8
10
= 0.8 l/s
For result 1 flowrate, Q2 =
8
12
= 0.667 l/s
For result 1 flowrate Q3 =
8
11
= 0.727 l/s
Average flow rate Q =
0.8+0.667+0.727
3
= 0.731 l/s
47. 40
Converting this to m3/s =
0.731
1000
= 0.000731 m3/s
Practical power of the pump = Qhρg= 0.000731 × 1.5 × 1000 × 9.81 = 10.8 W
efficiency of the pump,η =
power output
power input
=
10.81
18
= 0.6 = 60%
4.3 Limitation of the system
a. Unless a manual is provided it is difficult for an illiterate to connect the system
b. The pump used is only for clean water, a special pump shall be required for river water,
or any muddy water.
c. Initial cost of the system is high but long time costs are very low.
4.4 Challenges Faced
a. The ultrasonic sensor had a tolerance of ± 5% thus could not accurately give the reading.
b. The pressure in the storage bucket was too low to flow through the solenoid valve at a
faster rate.
c. Financial constraints made it difficult to get all the required components and the required
specifications example it was difficult to acquire a solar panel.
4.5 Facilities that were used
In order to design and fabricate this project successfully the following facilities were necessary:
a. Plumbing workshop
b. Electrical and electronics laboratory
c. Fluids laboratory
48. 41
CHAPTER FIVE
CONCLUSION AND DISCUSION
5.1 Conclusion
Hunger crisis is a universal problem. Most people suffer due to the little capacity to practice
agriculture. Those trying to practice agriculture also face many challenges such as raising cost of
energy, raising cost of labor among others. The project provides an easy and simple way to solve
these problems.
The objectives of the project were met. The automatic irrigation management system was
designed and fabricated. The system worked as per the expectations and effectively.
By implementing the proposed system the government and the farmers benefit. For the
government this project is a solution for energy crisis and also a solution to the hunger crisis
hitting the country frequently. By using the automatic irrigation system it optimizes the usage of
water by reducing wastage and reduces the human intervention for farmers thus water and time is
also conserved. The excess energy produced using solar panels can also be for domestic purposes
with small modifications in the system circuit, which can be a source of the revenue of the
farmer, thus encouraging farming in Kenya and same time giving a solution for energy crisis.
Proposed system is easy to implement and environment friendly solution for irrigating fields.
The system requires minimal maintenance and attention as they are self-starting and stopping. To
further enhance the daily pumping rates tracking ways can easily be implemented by
incorporating a GSM module. This system demonstrates the feasibility and application of using
solar power to provide energy for the pumping requirements and for sprinkler irrigation. Even
though there is a high initial capital investment required for this system to be implemented, the
overall benefits are high and in long run this system is economical.
5.2 Recommendation
There is a need to evaluate the present institutional framework for renewable energy and modern
farming methods education in Kenya and make suggestions for a shift in policy toward
increasing its adoption rate. The awareness by people of their technical issues, and governmental
subsidy plans could provide even more benefits to people living in the arid areas. The project can
be implemented anywhere where there is a source of water. I urge the government and stake
holders to invest on the project and implement it. The project can be improved by developing
smart greenhouses where the humidity and temperature can also be controlled
49. 42
WORKING SCHEDULE
Table 5. 1 Working Schedule
JAN FEB MAR APR MAY JUN JUL
Research & project identification
Literature review and more research
Proposal write up
Class presentation
Further research
Departmental presentation
Material acquisition
Fabrication
Final write up and testing
Final presentation
50. 43
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