Automated Plant Watering System

MINI PROJECT

AUTOMATED PLANT WATERING SYSTEM

Overview So what is this project? What does it do?

Basically this is a soil moisture monitoring system, which detects if the moisture content in the soil is above or below a certain satisfactory threshold value. If it goes below a certain critical point, it is time to water the plant until the soil surrounding the plant is moist enough. An arrangement of a DC motor and a servo motor is used to control the watering mechanism.

Before we start with the project itself, let’s see what led us to take up this challenge to make this automated watering system.

In this 21st century, climate change and depletion of resources have become a major issue to deal with. With the ever growing population and increased demand for natural resources we find ourselves in a middle of a crisis, a crisis which calls for immediate action. Sustainable development must be adopted by each one of us, both on a personal level and socio-industrial level. Among the teeming natural resources which make life possible on earth, perhaps the most important is water. Water shortage has become a crucial issue in most parts of the world. Recently, the state of Maharashtra in India is facing a severe drought which has already claimed many lives. Hence we see that water conservation is of utmost importance.

Conventional irrigation methods use a lot of water, and needless to say, a lot of it is wasted on a daily basis. With the help of advanced methods of irrigation, which should ideally use just the correct amount of water needed for the plants, we could save a considerable amount of water. With the help of soil moisture sensors, we could use just the right amount of water needed for irrigation – and that is the motivation of this project.

Equipments used

• Arduino Uno• Soil moisture sensor module• Motor driver IC L293D• Servo motor• Pump motor• 12V DC adapter• Vero board• Wires and jumper cords.

Circuit Diagram

The main elements of the circuit

• The Arduino• Soil Moisture Sensor• Motor driver IC L293D• Servo motors and DC motors

The Arduino The Arduino is an open-source microcontroller based kit for building

digital devices and interactive objects that can sense and control objects in the physical world.

The Arduino board provides sets of digital and analog I/O pins that can be interfaced to various expansion boards ("shields") and other circuits.

The board features RS-232 serial communication interface, including USB on some models, for loading programs from personal computers.

For programming the microcontrollers, the Arduino has a specific software associated with it which provides an integrated development environment (IDE) based on the Processing project, which includes support for the C and C++ programming languages.

The Arduino

Soil Moisture Sensor Module Soil moisture sensors measure the volumetric water

content in soil. 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 Soil Moisture Sensor uses capacitance to measure dielectric permittivity of the surrounding medium. In soil, dielectric permittivity is a function of the water content. The sensor creates a voltage proportional to the dielectric permittivity, and therefore the water content of the soil.

The sensor averages the water content over the entire length of the sensor. There is a2 cm zone of influence with respect to the flat surface of the sensor.

What Does A Soil Moisture Sensor Look Like?Here it is.

Motor driver IC L293DL293D is a motor driver integrated circuit which

can control a set of two DC motors simultaneously.

The L293D uses 5V for its own power and external power source is needed to drive the motors.

Motor driver is basically a current amplifier which takes a low-current signal from the microcontroller and gives out a proportionally higher current signal which can control and drive a motor.

The special feature of this IC is controlling the direction of rotation of the motor, which is done with the help of an H-Bridge.The switches S1,S2,S3 and S4 are realized by MOSFETS and with the help of different combinations of them turning on or off controls the direction of rotation of the motor shaft.

IC L293D

Servo Motor

A servo motor is a rotary actuator that allows for precise control of angular or linear position, velocity and acceleration.

It consists of a suitable motor coupled to a sensor for position feedback.

The input to its control is some signal, either analogue or digital, representing the position commanded for the output shaft.

The Arduino controls the rotation by specifying the exact angle of rotation.

DC Motor A DC motor is any of a class of electrical machines that

converts direct current electrical power into mechanical power.

The most common types of DC motors rely on the forces produced by magnetic fields.

A DC motor's speed can be controlled over a wide range, using either a variable supply voltage or by changing the strength of current in its field windings.

Now let’s get to the working…

• The Soil moisture sensor continuously monitors the volumetric moisture content in the soil and sends that information to the Arduino with values lying in the range 0 to 1023.

• If the soil moisture content goes below a certain point, which is decided by the threshold value given in the Arduino code, the Arduino signals the servo motor and the dc motor to start the watering mechanism.

• As soon as the Arduino decides that the soil needs watering, it tells the servo motor how much to rotate and along with it the water holding container is tilted to let the water flow.

• Keep in mind that all this while the pump motor, that is, the DC Motor is running to maintain a steady flow of water.

The Realised Project

The Big Picture• In this project, we have merely built a prototype.

But the advantages of this project are numerous. If we can implement this technology in the real world, a lot of water can be saved. The world uses about 70% of freshwater for irrigation and on the other hand irrigation multiplies yield of most crops by almost 2 to 5 times. So irrigation seems to be a necessary evil. The best solution out of this is controlled usage of water for irrigation purpose – a purpose successfully fulfilled by this project.

Here is an animation showing the working of the project…

The IC L293D tells the pump motor to rotate

The Arduino decides whether soil moisture is

above or below threshold valueThe soil moisture sensor

measures soil moisture content

Information is passed on to the motor driver IC L293D

If moisture content is low, the servo motor does its job and the watering mechanism is activated

END OF PROJECT