Design and construction of automatic plant irrigation system that sense soil moisture using microcontroller


Design and construction of automatic plant irrigation system that sense soil moisture using microcontroller

CHAPTER ONE/Introduction

Background of the Study

Irrigation is the artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and re vegetation of disturbed soils in dry areas and during periods of inadequate rainfall. When a zone comes on, the water flows through the lateral lines and ultimately ends up at the irrigation emitter (drip) or sprinkler heads. Many sprinklers have pipe thread inlets on the bottom of them which allows a fitting and the pipe to be attached to them. The sprinklers are usually installed with the top of the head flush with the ground surface. When the water is pressurized, the head will pop up out of the ground and water the desired area until the valve closes and shuts off that zone. Once there is no more water pressure in the lateral line, the sprinkler head will retract back into the ground. Emitters are generally laid on the soil surface or buried a few inches to reduce evaporation losses.

Water is a resource that all living species need. It is therefore very precious and has to be used with moderation to be preserved for the generations to come. Agriculture is an industry that uses a lot of water. Most of the time, this resource is not used efficiently and substantial amounts of water are wasted. In the near future, these wastes will represent a large sum of money. The ones who manage this resource efficiently will be winning time and money.

In this project report, an automated irrigation system is suggested to minimize the water input and human intervention, while satisfying the plants needs. First, the details of the problem are summarized. The objective and the scope of the project are described. Some general approaches to the design are reviewed. The results and conclusions of an experiment to determine the required amounts of water are discussed.  Then, the suggested design is explained in detail with the purpose, requirements and constraints, simulation and test results for each of its parts. A brief cost analysis is performed to estimate the viability of such a project on the market. Finally, the design is criticized, and suggestions are made for future improvements.

An automatic irrigation system does the operation of a system without requiring manual involvement of persons. Every irrigation system such as drip, sprinkler and surface gets automated with the help of electronic appliances and detectors such as computer, timers, sensors and other mechanical devices.

Healthy plants can transpire a lot of water, resulting in an increase in the humidity of the greenhouse air. A high relative humidity (above 80-85%) should be avoided because it can increase the incidence of disease and reduce plant transpiration. Sufficient venting or successive heating and venting can prevent condensation on plants surfaces and the greenhouse structure. The use of cooling systems during the warmer summer months increases the greenhouse air humidity. During periods with warm and humid outdoor conditions, humidity control inside the greenhouse can be a challenge. Greenhouses located in dry, dessert environments benefit greatly from evaporative cooling systems because large amounts of water can be evaporated into the incoming air, resulting in significant temperature drops.


Since the relative humidity alone does not tell us anything about the absolute water holding capacity of air, a different measurement is sometime used to describe the absolute moisture status of the soil. The vapor pressure deficit is a measure of the difference between the amount of moisture the air contains at a given moment and the amount of moisture it can hold at that temperature when the air would be saturated. Pressure deficit measurement can tell us how easy it is for plants to transpire: higher values stimulate transpiration (but too high can cause wilting), and lower values inhibit transpiration and can lead to condensation on leaf and surfaces.

 Types of Irrigatio

Ditch Irrigation

Ditch Irrigation is a rather traditional method, where ditches are dug out and seedlings are planted in rows. Siphon tubes are used to move the water from the main ditch to the canals.

Terraced Irrigation

This is a very labor-intensive method of irrigation where the land is cut into steps and supported by retaining walls. . The flat areas are used for planting and the idea is that the water flows down each step watering each plot. This allows steep land to be used for planting crops.

Drip Irrigation

This is known as the most water efficient method of irrigation. Water drops right near the root zone of a plant in a drip- ping motion. If the system is installed properly you can steadily reduce the loss of water through evaporation and runoff.

Sprinkler System

This is an irrigation system based on overhead sprinklers, sprays or guns, installed on permanent risers. You can also have the system buried underground and the sprinklers rise up when water pressure rises, which is a popular irrigation system for use on golf courses and parks.

Rotary Systems

This method of irrigation is best suited for larger areas, for the sprinklers can reach distances of up to 100 feet. The word “Rotary” is indicative of the mechanical driven sprinklers moving in a circular motion, hence reaching greater distances. This system waters a larger area with small amounts of water over a long period of time.

Statement of the Problem

Irrigation of plants is usually a very time-consuming activity; to be done in a reasonable amount of time, it requires a large amount of human resources. Traditionally, all the steps were executed by humans.  Nowadays, some systems use technology to reduce the number of workers or the time required to water the plants. With such systems, the control is very limited, and many resources are still wasted.

Water is one of these resources that are used excessively. Mass irrigation is one method used to water the plant. This method represents massive losses since the amount of water given is in excess of the plants needs. The excess water is evacuated by the holes of the pots in greenhouses, or it percolates through the soil in the fields.

The contemporary perception of water is that of a free, renewable resource that can be used in abundance. However, this is not reality; in many parts of North America, water consumption is taxed. It is therefore reasonable to assume that it will soon become a very expensive resource everywhere.

In addition to the excess cost of water, labour is becoming more and more expensive. As a result, if no effort is invested in optimizing these resources, there will be more money involved in the same process. Technology is probably a solution to reduce costs and prevent loss of resources.

Aim and Objectives

The aim of this project is to build an automatic plant irrigation system that sense soil moisture using microcontroller.

The following are objectives of the studies:

  • To reduce human interference and ensure proper irrigation
  • To minimize water loss and to maximize the efficiency of water used
  • To prevent over labour of the pumping machine and prevent it from getting bad or burned

The following aspects were considered in the choice of a design solution:

  1. Installation costs;
  2. Water savings;
  • Human intervention;
  1. Reliability;
  2. Power consumption;
  3. Maintenance;
  • Expandability.

A  critical  consideration  is  the installation  costs,  since costs  generally determine  the feasibility  and  viability  of  a  project.  The installation must be simple enough for a domestic user. The water savings was also an important aspect, since there is a demand to minimize water loss and to maximize the efficiency of water used. Since the objective is to minimize the cost of labour, minimal supervision and calibration must be needed. The system must operate with optimized consistency. The power consumption must also be monitored. For maintenance, the replacement parts must be readily available and easy to install in the case of failure. Finally, the possibility for implementing the system at a larger scale (e.g. in greenhouses) should be investigated.

Justification of the Work

The increasing world population has lead to exponential increase in food demand. This event has necessitated the need for more land to be cultivated. Due to change of weather patterns brought about by global warming, irrigation remains as the only reliable method of crops production. With more and more land now being under irrigation there is a need for optimal use of water.

Over the last few years knowledge in electronics and computation has been used to solve present day challenges. In the forefront of the electronics revolution has been the microcontroller. The microcontroller has been used together with various sensors to measure and control physical quantities like temperature, humidity, heat and light. By controlling these physical quantities using the microcontroller; automatic systems have been achieved.

Irrigation systems in crop production can and has also been automated. This solves the challenge brought about by the unreliability of climate changes thus need for water optimization. Automation of the soil moisture sensor irrigation systems is one of the most convenient, efficient and effective method of water optimization. The systems helps in saving water and thus more land can be brought under irrigation. Crops grown under controlled conditions tend to be healthier and thus give more yields. Controlled watering system results in reduction of fertilizer use and thus fertilizer costs go down.

Scope of the Study

This project involves the evolution of watering manually to watering automatically. The  controlling  of  the  automatic  watering  system  is  use  in  a house, institution or any organization with flowers planted for decoration.  Sensor used to control the watering system is soil moisture sensor.  Other than that, this system should also monitor the water level.

Significance of the Study

The continuous increasing demand of food requires the rapid improvement in food production technology. In a country like Nigeria, where the economy is mainly based on agriculture and the climatic conditions are isotropic, still we are not able to make full use of agricultural resources. The main reason is the lack of rains & scarcity of land reservoir water. The continuous extraction of water from earth is reducing the water level due to which lot of land is coming slowly in the zones of un-irrigated land. Another very important reason of this is due to unplanned use of water due to which a significant amount of water goes to waste. This problem can be rectified if we use microcontroller based automated irrigation system in which the irrigation will take place only when there will be acute requirement of water.

Advantages of the System

  1. Saves water – Studies show that drip irrigation systems use 30 – 50% less water than conventional watering methods, such as sprinklers.
  2. Improves growth – Smaller amounts of water applied over a longer amount of time provide ideal growing conditions. Drip irrigation extends watering times for plants, and prevents soil erosion and nutrient runoff. Also, because the flow is continuous, water penetrates deeply into the soil to get well down into the root zone.
  • Discourages weeds – Water is only delivered where it’s needed.
  1. Saves time – Setting and moving sprinklers are not required. A timer delay as per environment can be added to the system for automatic watering.
  2. Helps control fungal diseases, which grow quickly under moist conditions. Also, wet foliage can spread disease.
  3. Adaptable – A drip irrigation system can be modified easily to adjust to the changing needs of a garden or lawn.
  • Simplest Method – Start by drawing a map of your garden and yard, showing the location of plantings. Measure the distances required for lengths of hose or plastic tubing to reach the desired areas.

Others Advantages

  • Highly sensitive
  • Works according to the soil condition
  • Fit and Forget system
  • Low cost and reliable circuit
  • Complete elimination of manpower
  • Can handle heavy loads up to 7A
  • System can be switched into manual mode whenever required

Area of Application

  • Roof Gardens
  • Lawns
  • Agriculture Lands
  • Home Gardens


The increasing demand of the food supplies requires a rapid improvement in food production technology. In many countries where agriculture plays an important part in shaping up the economy and the climatic conditions are isotropic, but still we are not able to make full use of agricultural resources. One of the main reasons is the lack of rains & scarcity of land reservoir water. Extraction of water at regular intervals from earth is reducing the water level as a result of which the zones of un-irrigated land are gradually increasing.

Also, the unplanned use of water inadvertently results in wastage of water. In an Automated Irrigation System using ATMega328, the most significant advantage is that water is supplied only when the moisture in soil goes below a pre-set threshold value. This saves us a lot of water. In recent times, the farmers have been using irrigation technique through the manual control in which the farmers irrigate the land at regular intervals by turning the water-pump on/off when required. This process sometimes consumes more water and sometimes the water supply to the land is delayed due to which the crops dry out. Water deficiency deteriorates plants growth before visible wilting occurs. In addition to this slowed growth rate, lighter weight fruit follows water deficiency.

This problem can be perfectly rectified if we use Automated Irrigation System in which the irrigation will take place only when there will be intense requirement of water, as suggested by the moisture in the soil.



Thesis Outline

This study comprises of five different chapters arranged sequentially. Chapter one gives a brief history of the various forms of locks and their technological advancements. Chapter two explains the operating principles of the various stages involved in the digital combination lock using microcontroller. In chapter three, the design and implementation of the whole project work is discussed fully. Chapter four presents the results and discussions drawn from tests performed on the system, while lastly; Chapter gives a conclusion and recommendation on the entire work