The Project

The system has 4 basic modules:

1) Solar Module

2) Sensors

3) Pumps

4) Circuitry

(1) SOLAR MODULE

(2) SENSORS

We've used a total of 4 sensors. 3 for moisture sensing and 1 for rain water level sensing. One terminal of the sensors is grounded and the other is connected to a transistor circuit.

When the land is dry then there is no connection between both the terminals and the transistor circuit gives a logic high output (converted by ADC) to the micro-controller.

When water flows and the soil becomes wet then both the terminals get connected and the transistor circuit is grounded. Thus, logic 0 is given to the micro-controller. The micro-controller makes the decision on the basis of these inputs and the code.

(3) PUMPS

For the purpose of demonstration we have used A.C. pumps. In the fields, submersible pumps or turbine pumps may be used.

Submersible Pumps:

Submersible pumps are installed completely underwater, including the motor. The pump consists of an electric motor and pump combined in a single unit. Typically the pump will be shaped like a long cylinder so that it can fit down inside of a well casing. Although most submersible pumps are designed to be installed in a well, many can also be laid on their side on the bottom of a lake or stream. Another common installation method for lakes and rivers is to mount the submersible pump underwater to the side of a pier pile (post). Submersible pumps don't need to be primed since they are already under water. They also tend to be more efficient because they only push the water, they don't need to suck water into them. Most submersible pumps must be installed in a special sleeve if they are not installed in a well, and sometimes they need a sleeve even when installed in a well. The sleeve forces water coming into the pump to flow over the surface of the pump motor to keep the motor cool. Without the sleeve the pump will burn up. Because the power cord runs down to the pump through the water it is very important that it be protected from accidental damage. You wouldn't want a boat tangled up in the cord or a snapping turtle or alligator to bite through it!

Turbine Pumps:

A turbine pump is basically a centrifugal pump mounted underwater and attached by a shaft to a motor mounted above the water. The shaft usually extends down the center of a large pipe. The water is pumped up this pipe and exits directly under the motor. Turbine pumps are very efficient and are used primarily for larger pump applications. Often they consist of multiple stages, each stage is essentially another pump stacked on top of the one below. It works like a train with multiple engines hitched together pulling it, each stage would be a engine. Turbine pumps are typically the type of pumps you see on farms. When you see a huge motor mounted on its end and a pipe coming out sideways below the motor, that is most likely the motor for a turbine pump down inside the well. The turbine pump is mounted in a large concrete vault with a pipe connecting it to the lake. The water flows by gravity into the vault where it enters the pump. The pump motors are suspended over the vault on a frame. A jet pump is similar to a turbine pump but it works by redirecting water back down to the intake to help lift the water.

(4) CIRCUITRY & CODE

Note: This is not the actual connection diagram as PIC16F72 wasn't available in my ISIS library, although, this is the basic circuit diagram.

COMPONENTS & SPECIFICATIONS:

PROGRAMMING:

Code : Smart Irrigation System

The code is pretty simple. First, the ADC converter is activated, the input and output ports are set (PORT B is used for interfacing the LCD, Pin no. 2 and 3 of PORT C are used for providing the output to the ULN 2003A IC, Pin no. 4, 5 & 6 for inputs from moisture sensors and Pin no. 7 for input from rain water level sensor) and the LCD is initialized.

Then the condition of the three moisture sensors is checked. If they are dry i.e. their output is logic '0'
if((PORTC.F4 == 0)&&(PORTC.F5 == 0)&&(PORTC.F6 == 0))
then the program checks whether there is water in the rain water tank. If the output of the rain water level sensor is logic '1'
if(PORTC.F7 == 1)
then it means that there is water in the tank and the irrigation will start.

As soon as the moisture sensors become wet they give output as logic '1'
if((PORTC.F4 == 1)&&(PORTC.F5 == 1)&&(PORTC.F6 == 1))
the irrigation is stopped and 'Irrigation done' is displayed on the LCD.
Lcd_Cmd(_LCD_CLEAR);
Lcd_Out(1,4, "IRRIGATION");
Lcd_Out(2,7, "DONE");

If the output of the rain water level sensor is logic '0'
if(PORTC.F7 == 0)
then ground water is used for irrigation.

This enables the water to get in the field only when it is required.