Design And Construction Of Soil Moisture Sensor

The moisture of the soil plays an essential role in agricultural practice as well as in gardens for plants. As nutrients in the soil provide the food to the plants for their growth. Supplying water to the plants is also essential to change the temperature of the plants.

Original price was: ₦ 3,000.00.Current price is: ₦ 2,999.00.



The moisture of the soil plays an essential role in agricultural practice as well as in gardens for plants. As nutrients in the soil provide the food to the plants for their growth. Supplying water to the plants is also essential to change the temperature of the plants. The temperature of the plant can be changed with water using the method like transpiration. And plant root systems are also developed better when rising within moist soil. Extreme soil moisture levels can guide to anaerobic situations that can encourage the plant’s growth as well as soil pathogens. This work discusses the design of a soil moisture sensor.



1.0                                                        INTRODUCTION

Soil moisture sensors measure the volumetric water content in soil. Since the direct gravimetric measurement of free soil moisture requires removing, drying, and weighting of a sample, soil moisture sensors measure the volumetric water content indirectly by using some other property of the soil, such as electrical resistance, dielectric constant, or interaction with neutrons, as a proxy for the moisture content. The relation between the measured property and soil moisture must be calibrated and may vary depending on environmental factors such as soil type, temperature, or electric conductivity. Reflected microwave radiation is affected by the soil moisture and is used for remote sensing in hydrology and agriculture. Portable probe instruments can be used by farmers or gardeners.

This soil moisture sensor measures soil moisture levels by capacitive sensing rather than resistive sensing like other sensors in the market. It is made of corrosion resistant material which gives it an excellent service life.
Insert it in to the soil around your plants and impress your friends with real-time soil moisture data! This module includes an on-board voltage regulator which gives it an operating voltage range of 3.3 ~ 5.5V. It is perfect for low-voltage MCUs, both 3.3V and 5V. For compatibility with a Raspberry Pi it will need an ADC converter. This sensor is compatible with our 3-pin “Gravity” interface, which can be directly connected to the Gravity I/O expansion shield.  The aim of this project is to build an automatic soil moisture sensor using op-amp as the heart of the project.

1.2                                       PROBLEM STATEMENT

Traditionally, watering of our farm land is been carried out by farmer, and the process is been done when farmers think or assume that water have dried on their farm land. This consumes huge amount of time, it requires a large amount of human resources. 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. This is the purpose why soil moisture was invented.

1.3                                     AIM AND OBJECTIVES OF THE STUDY

The aim of this project is to build an automatic soil moisture sensor using op-amp.

The following are objectives of the studies:

  • To reduce human interference and ensure proper watering
  • 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

1.4                                              PURPOSE OF THE PROJECT

The purpose of this work is to ensure adequate and consistent water supply for farm land.

1.5                                              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.

1.6                                        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.

1.7                                          APPLICATION OF THE PROJECT


Measuring soil moisture is important for agricultural applications to help farmers manage their irrigation systems more efficiently. Knowing the exact soil moisture conditions on their fields, not only are farmers able to generally use less water to grow a crop, they are also able to increase yields and the quality of the crop by improved management of soil moisture during critical plant growth stages.

Landscape irrigation

In urban and suburban areas, landscapes and residential lawns are using soil moisture sensors to interface with an irrigation controller. Connecting a soil moisture sensor to a simple irrigation clock will convert it into a “smart” irrigation controller that prevents irrigation cycles when the soil is already wet, e.g. following a recent rainfall event.


Soil moisture sensors are used in numerous research applications, e.g. in agricultural science and horticulture including irrigation planning, climate research, or environmental science including solute transport studies and as auxiliary sensors for soil respiration measurements.

Simple sensors for gardeners

Relatively cheap and simple devices that do not require a power source are available for checking whether plants have sufficient moisture to thrive. After inserting a probe into the soil for approximately 60 seconds, a meter indicates if the soil is too dry, moist or wet for plants.

1.8                                           LIMITATION OF THE PROJECT

The sensors don’t measure earth’s resistance. And the device will stop working as soon as the sensor is rusted.

1.9                                         METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

  1. Study of the previous work on the project so as to improve it efficiency.
  2. Draw a block diagram.
  • Test for continuity of components and devices,
  1. Design and calculation for the device was carried out.
  2. Studying of various component used in circuit.
  3. Construction of the circuit was carried out.
  • Finally, the whole device was cased and final test was carried out.

1.10                                                      PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied,  chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.






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