Design of Automatic Plant Irrigation System Using Microcontroller

ABSTRACT

Automatic plant irrigation system rise as a good choice and alternative to traditional irrigation methods since it is saving time and effort that are consumed by traditional methods where people are compelled to stop doing their important activities. The aim of this thesis is to develop a microcontroller-based automatic irrigation system. This system will run automatically by referring to the level of soil moisture. The humidity sensor type connected to the microcontroller is soil moisture sensor YL-69. The level of moisture will be displayed on the LCD screen to inform the user about their plant condition. The system was tested on three soil types (loam, sand and red) . From the results, we can observe that the red soil has lower resistance by increasing the water contents.

TABLE OF CONTENTS

Page

I آيت

Dedication II

Acknowledgements III

Abstract IV

V يستخهص

Table Of Contents VI

List of figures IX

List of Tables XI

List Of Abbreviations XII

Chapter One: Introduction 1

1.1 General 2

1.2 Problem statement & solution 3

1.4 Objectives 3

1.5 Methodology 4

1.6 Thesis Outline 4

Chapter Two: Literature review 5

2.1 Introduction 6

2.2 Microcontroller 8

2.3 Humidity Sensor 9

2.3.1 relevant moisture terms 9

2.3.2 classification & principles 10

2.3.3 Sensing Principle 10

2.3.3.1 Sensors based on capacitive effect 10

2.3.3.2 Sensors based on resistive effect 11

2.3.4 soil moisture sensor 12

2.4 converters 13

2.4.1 Filters 13

2.4.2 Analog-to-digital converters (ADCs) 13

2.4.2.1 Gray code 16

2.4.2.2 Haw dose an A/D converter work 16

2.5 Water pump 20

Chapter three: Electronic circuit design and software 21

3.1. Introduction 22

3.1.1 System definition 22

3.1.2 Circuit design 22

3.1.3 PCB design and fabrication 22

3.1.4 Hardware modification 22

3.1.5 Software design 22

3.1.6 Integration and final testing 22

3.2. Hardware Implementation 23

3.2.1. Component selection and description 23

3.2.2. Soil Moisture Sensor (YL-69) 24

3.2.2.1Digital potentiometer 25

3.2.2.2 LM393 comparator 25

3.2.3. Microcontroller 26

3.2.3.1 Pin description 27

3.2.4. LCD-1602A 31

3.2.5. High Current Darlington Transistor (ULN2803) 32

3.2.6. 5V DC Relay 33

3.2.7. Piezoelectric buzzer 33

3.2.8. Hardware details of system designed 34

3.2.8.1 Microcontroller PIC16F877A 35

3.2.8.2 Soil moisture sensor 36

3.2.8.3 LCD-1602A 36

.3.2.8.4 High current Darlington transistor 36

3.2.8.5 Power supply section 36

3.3. Software design and development: 37

CHAPTER FOUR: RESULTS AND DISCUSSION 40

4.1. Results 41

4.2. Discussion 42

CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS 47

5.1. Conclusion 48

5.2. Recommendations 48

REFERENCES 49

APPENDICES 51

Appendix A 52

Appendix B 57

Appendix C 61