project report

1. SOIL MOISTURE SENSOR BYAUTO IRRIGATION SYSTEM
A MAJOR PROJECT REPORT
PLANING & LITERATURE SURVEY
Submitted to the
Rajiv Gandhi Proudyogiki Vishwavidyalaya (R.G.P.V)
In the partial fulfilment of the requirements for the award of the
Degree of
BACHELOR OF ENGINEERING
IN
ELECTRICAL & ELECTRONICS ENGINEERING
By
RAJKAPUR KUMAR 0187EX111038
MANORANJAN KUMAR 0187EX111026
KISHAN KUMAR 0187EX111023
RITESHKUMAR 0187EX111043
OMPRAKASH KUMAR 0187EX111034
Under the guidance of
Prof. MONIKA SINGH RANA
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEEING
SAGAR INSTITUTE OF SCIENCE & TECHNOLOGY
Bhopal (M.P.)
BATCH 2011-15

2. CANDIDATE’S DECLARATION
I hereby declare that the work, which is being presented in this project entitled
“SOIL MOISTURE SENSOR BY AUTO IRRIGATION SYSTEM” in partial fulfillment
of the requirement for the award of the degree of Bachelor of Engineering in “Electrical &
Electronics”.
The work has been carried out at Department of Electrical & Electronics
Engineering, Sagar Institute of Science & Technology (SISTec) Bhopal. It is an authentic
record of my work carried out under the guidance of Prof. Monika Singh Rana, Department
of Electrical & Electronics SISTec, Bhopal. I have not submitted the matter embodied in this
project for the award of any other degree or diploma.
Rajkapur kumar
0187ex111038
Manoranjan kumar
0187ex111026
Kishan kumar
0187ex111023
Ritesh kumar
0187ex111043
Omprakash kumar
0187ex111034

3. CONTENTS
1. ABSTRACT……………………………………………………..1
2. INTRODUCTION.......................................................................2
3. HARD WARE EQUIPMENTS.......................................................3
4. BLOCK DIAGRAM………………………………………………………………………………………….4
5. POWER SUPPLY……………............................................................4
6. CIRCUIT DIAGRAM……………………….................................................6
7. SENSOR…...................................................................................7
8. MICROCONTROLLER(ATMEGA8L)……………................................9
9. LCD...........................................................................................12
10. RELAYS …………….......................................................................14
11. ADVANTAGE ……………………………………………………………………………………………….16
12. FUTURE SCOPE………………………………………......................................16
13. CONCLUSION…………………………………………………………………………………………….…17
14. REFERENCES………………………………………………………………………………………………..17

4. ABSTRACT
Appropriate soil water level is a necessary pre-requisite for optimum plant
growth. Also, water being an essential element for life sustenance, there is the
necessity to avoid its undue usage. Irrigation is a dominant consumer of water.
This calls for the need to regulate water supply for irrigation purposes. Fields
should neither be over-irrigated nor under-irrigated. Over time, systems have
been implemented towards realizing this objective of which automated
processes are the most popular as they allow information to be collected at high
frequency with less labor requirements. Bulk of the existing systems employ
micro-processor based systems. These systems offer several technological
advantages but are unaffordable, bulky, difficult to maintain and less accepted
by the technologically unskilled workers in the rural scenario.
The objective of this project is to design a simple, easy to install methodology
to monitor and indicate the level of soil moisture that is continuously controlled
in order to achieve maximum plant growth and simultaneously optimize the
available irrigation resources. Project mainly focuses on measuring the soil
moisture and measuring the Humidity .
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5. INTRODUCTION
Agriculture, for decades, had been associated with the production of basic food
crops. Agriculture and farming were synonymous so long as farming was not
commercialized. But as the process of economic development accelerated,
many more other occupations allied to farming came to be recognized as a part
of agriculture.
At present, agriculture besides farming includes forestry, fruit cultivation, dairy,
poultry, mushroom, bee keeping, arbitrary, etc. Today, marketing, processing,
distribution of agricultural products etc. are all accepted as a part of modern
agriculture.
Thus, agriculture need the mass production for economy growth. So need fast
production with balance parameter like water level humidity fertilizers level and
other thing for the good quality of crops. Here present the concept of
autonomous agriculture. In that the humidity of soil is measure by the sensor
and it maintain as per crops requirement.
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6. HARD WARE EQUIPMENTS
• POWER SUPPLY BLOCK
• MICROCONTROLLER (ATMEGA8L)
• LCD
• HUMIDITY SENSOR
• BC547 TRANSISTOR
• RELAY
• 1N4007
• LED
• RESISTORS & CAPACITORS
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7. BLOCK DIAGRAM
POWER SUPPLY: - The input to the circuit is applied from the regulated
power supply. The a.c. input i.e., 230V from the mains supply is step down by
the transformer to 12V and is fed to a rectifier. The output obtained from the
rectifier is a pulsating d.c voltage. So in order to get a pure d.c voltage, the
output voltage from the rectifier is fed to a filter to remove any a.c components
present even after rectification. Now, this voltage is given to a voltage regulator
to obtain a pure constant dc voltage.
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 a.c input available at the mains supply i.e., 230V is
to be brought down to the required voltage level. This is done by a transformer.
Thus, a step down transformer is employed to decrease the voltage to a required
level.
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Humidity
sensor
Microcontroller Relay Motor Pump

8. Rectifier: - The output from the transformer is fed to the rectifier. It converts
A.C. into pulsating D.C. The rectifier may be a half wave or a full wave
rectifier. In this project, a bridge rectifier is used because of its merits like good
stability and full wave rectification. The Bridge rectifier is a circuit, which
converts an ac voltage to dc voltage using both half cycles of the input ac
voltage. The Bridge rectifier circuit is shown in the figure. The circuit has four
diodes connected to form a bridge. The ac input voltage is applied to the
diagonally opposite ends of the bridge. The load resistance is connected
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
OFF state. The conducting diodes will be in series with the load resistance RL
and hence the load current flows through RL. For the negative half cycle of the
input ac voltage, diodes D2 and D4 conduct whereas, D1 and D3 remain OFF.
The conducting diodes D2 and D4 will be in series with the load resistance RL
and hence the current flows through RL in the same direction as in the previous
half cycle. Thus a bi-directional wave is converted into a unidirectional wave.
Filter: - Capacitive filter is used in this project. It removes the ripples from the
output of rectifier and smoothens the D.C. Output received from this filter is
constant until the mains voltage and load is maintained constant. However, if
either of the two is varied, D.C. voltage received at this point changes.
Therefore a regulator is applied at the output stage.
Voltage regulator: - As the name itself implies, it regulates the input applied
to it. A voltage regulator is an electrical regulator designed to automatically
maintain a constant voltage level. In this project, power supply of 5V and 12V
are required. In order to obtain these voltage levels, 7805 and 7812 voltage
regulators are to be used. The first number 78 represents positive supply and the
numbers 05, 12 represent the required output voltage levels. The L78xx series
of three-terminal positive regulators is available in TO-220, TO-220FP, TO-3,
D2PAK and DPAK packages and several fixed output voltages, making it
useful in a wide range of applications.
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9. These regulators can provide local on-card regulation, eliminating the
distribution problems associated with single point regulation. Each type
employs internal current limiting, thermal shut-down and safe area protection,
making it essentially indestructible. If adequate heat sinking is provided, they
can deliver over 1 A output current. Although designed primarily as fixed
voltage regulators, these devices can be used with external components to
obtain adjustable voltage and currents.
CIRCUIT DIAGRAM
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10. SENSORS
A sensor is a converter that measures a physical quantity and converts it into a
signal which can be read by an observer or by an (today mostly electronic)
instrument.
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's sensitivity indicates how much the sensor's output changes when the
measured quantity changes.
Soil moisture sensor:
Working Principle
Soil moisture sensors measure the water content in soil. All plants need water to
grow and survive. Soil moisture sensors used to determine how much water are
needed to irrigate the plants.
Humidity and Temperature Sensor (DHT11)
Humidity is the amount of water vapor in the air. Water vapor is the gaseous
state of water and is invisible. Humidity indicates the likelihood of
precipitation, dew, or fog.
Humidity sensors detect the relative humidity of the immediate environments in
which they are placed. They measure both the moisture and temperature in the
air and express relative humidity as a percentage of the ratio of moisture in the
air to the maximum amount that can be held in the air at the current
temperature. As air becomes hotter, it holds more moisture, so the relative
humidity changes with the temperature.
Most humidity sensors use capacitive measurement to determine the amount of
moisture in the air. This type of measurement relies on two electrical conductors
with a non-conductive polymer film laying between them to create an electrical
field between them. Moisture from the air collects on the film and causes
changes in the voltage levels between the two plates. This change is then
converted into a digital measurement of the air’s relative humidity after taking
the air temperature into account.
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11. DHT11 sensor and pin description
Features
Low cost, long-term stability, relative humidity and temperature measurement,
excellent quality, fast response, strong anti-interference ability, long distance
signal transmission, digital signal output, and precise calibration.
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12. MICROCONTROLLER
A microcontroller (sometimes abbreviated µC, UC or MCU) is a small
computer on a single integrated circuit containing a processor core, memory,
and programmable input/output peripherals. Program memory in the form of
NOR flash or OTP ROM is also often included on chip, as well as a typically
small amount of RAM. Microcontrollers are designed for embedded
applications, in contrast to the microprocessors used in personal computers or
other general purpose applications.
Basic Peripherals in a Microcontroller:
1. I/O ports.
2. Interfacing with LCD
3. Analog to Digital Conversion (ADC)
4. USART
5. Timers/Counters
6. Interrupts
7. I2C
8. SPI
Uses of Microcontrollers:
Microcontrollers are used in automatically controlled products and devices,
such as automobile engine control systems, implantable medical devices,
remote controls, office machines, appliances, power tools, toys and other
embedded systems. By reducing the size and cost compared to a design that
uses a separate microprocessor, memory, and input/output devices,
microcontrollers make it economical to digitally control even more devices and
processes. Mixed signal microcontrollers are common, integrating analog
components needed to control non-digital electronic systems.
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13. About AVR Atmega8l:
a) I/O and Packages:
23 Programmable I/O Lines, 28-lead PDIP
b) Operating Voltages:
2.7V - 5.5V (ATmega8L)
4.5V - 5.5V (ATmega8)
C) Power Consumption:
At 4 MHz, 3V, 25°C:
Active: 3.6mA
Idle Mode: 1.0mA
Power-down Mode: 0.5Μa
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14. PIN DIAGRAM(ATMEGA8L)
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15. LCD (Liquid Crystal Display)
The display module consists of an LCD. The LCD used here is JHD 161A. The
function of LCD is given below:
Most LCDs with 1 controller has 14 Pins and LCDs with 2 controller has 16
Pins (two pins are extra in both for back-light LED connections). Pin
description is shown in the table below.
LCD PIN DESCRIPTION
PIN NO. NAME DESCRIPTION
Pin no. 1 D7 Data bus line 7 (MSB)
Pin no. 2 D6 Data bus line 6
Pin no. 3 D5 Data bus line 5
Pin no. 4 D4 Data bus line 4
Pin no. 5 D3 Data bus line 3
Pin no. 6 D2 Data bus line 2
Pin no. 7 D1 Data bus line 1
Pin no. 8 D0 Data bus line 0
Pin no. 9 EN1 Enable signal for row 0 and 1
Pin no. 10. R/W 0 = Write to LCD module
1 = Read from LCDmodule
Pin no. 11. RS 0=Instruction Input
1=Data Input
Pin no. 12. VEE Contrast adjust
Pin no. 13. VCC Power supply (+5V)
Pin no. 14. VSS Power supply (GND)
Pin no. 15. LED+ Backlight LED
Pin no. 16. LED- Backlight LED
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16. PIN DIAGRAM
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Parameter Symbol Testing
Criteria
STANDARD VALUES Unit
Min. Typ. Max.
Supply voltage VDD-VSS - 4.5 5.0 5.5 V
Input high voltage VIH - 2.2 - VDD V
Input low voltage VIL - -0.3 - 0.6 V
Output high voltage VOH IOH=02mA 2.4 - - V
Output low voltage VOL IOL=1.2mA - - 0.4 V
Operating voltage IDD VDD=5.0V - 1.5 3.0 V

17. RELAY
A relay is an electrically controllable switch widely used in industrial controls,
automobiles and appliances. The relay allows the isolation of two separate
sections of a system with two different voltage sources i.e., a small amount of
voltage/current on one side can handle a large amount of voltage/current on the
other side but there is no chance that these two voltages mix up.
Fig: Circuit symbol of a relay Operation-
when current flows through the coil, a magnetic field are created around the coil
i.e., the coil is energized. This causes the armature to be attracted to the coil.
The armature’s contact acts like a switch and closes or opens the circuit. When
the coil is not energized, a spring pulls the armature to its normal state of open
or closed. There are all types of relays for all kinds of applications.
Fig: Relay Operation and use of protection diodes
Transistors and ICs must be protected from the brief high voltage 'spike'
produced when the relay coil is switched off.
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18. The above diagram shows how a signal diode (eg 1N4148) is connected across
the relay coil to provide this protection. The diode is connected 'backwards' so
that it will normally not conduct. Conduction occurs only when the relay coil is
switched off, at this moment the current tries to flow continuously through the
coil and it is safely diverted through the diode. Without the diode no current
could flow and the coil would produce a damaging
high voltage 'spike' in its attempt to keep the current flowing.In choosing a
relay, the following characteristics need to be considered:
1. The contacts can be normally open (NO) or normally closed (NC). In the NC
type, the contacts are closed when the coil is not energized. In the NO type, the
contacts are closed when the coil is energized.
2. There can be one or more contacts. i.e., a different type like SPST (single
pole single throw), SPDT (single pole double throw) and DPDT (double pole
double throw) relays.
3. The voltage and current required to energize the coil. The voltage can vary
from a few volts to 50 volts, while the current can be from a few milliamps to
20milliamps. The relay has a minimum voltage, below which the coil will not
be energized. This minimum voltage is called the “pull-in” voltage.
4. The minimum DC/AC voltage and current that can be handled by the
contacts. This is in the range of a few volts to hundreds of volts, while the
current can be from a few amps to 40A or more, depending on the relay.
TRANSISTOR: - A transistor is a semiconductor device used to amplify and
switch electronic signals. It is made of a solid piece of semiconductor material,
with at least three terminals for connection to an external circuit. A voltage or
current applied to one pair of the transistor's terminals changes the current
flowing through another pair of terminals. Because the controlled (output)
power can be much more than the controlling (input) power, the transistor
provides amplification of a signal. Some transistors are packaged individually
but many more are found embedded in integrated circuits.
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19. BUZZER: - A buzzer or beeper is an audio signaling device, which may be
mechanical, electromechanical, or electronic. Typical uses of buzzers and
beepers include alarms, timers and confirmation of user input such as a mouse
click or keystroke.
FEASIBILITY: - The Sensor sense the humidity and give the Analog signal to
Pin no. 28 of microcontroller, the set of instruction in the microcontroller
calculate the humidity in the soil which mean the water level present in the soil.
Than as per crops requirement microcontroller start and stop water pump of
farms.
ADVANTAGES
 Consumes time-it the system is installed once then we can set a timer to
water for specific time interval.
 By using this type irrigation systems the position of the water is
effectively targeted where there is a need.
 High frequency due to water distribution.
DISADVANTAGES
 Design of the system is expensive
 High amount of energy is required
 Loss of water due to evaporation
FUTURE SCOPE:
This concept can be improved in future by enhancing it by integrating with
GSM technology, such that whenever the water pump switches ON/OFF, an
SMS is delivered to the concerned person regarding the status of the pump.
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20. CONCLUSION:-
The project “automatic irrigation system on sensing soil moisture content” has
been successfully studied. The project is developed to sense the moisture
content present in the soil. We can detect if the soil is dry or wet with motor
operation. The advantage of this project to decrease the human involvement and
still make certain appropriate irrigation systems with high efficiency.
REFERENCES:
www.efymag.com
www.elec circuit.com
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