This document describes an intelligent automatic plant irrigation system that waters plants regularly when the user is away. It uses soil sensors and a comparator circuit with an LM324 op-amp to monitor soil moisture levels. When the sensors detect dry soil, the comparator switches on an AC motor via a relay to water the plants. When the soil is wet, the comparator turns the motor off. The system provides an easy and low-cost way to irrigate plants without manual watering.

1. Intelligent Automatic Plant
Irrigation System

2. INDEX
 ABSTRACT
 BLOCK DIAGRAM
 POWER SUPPLY
 LM324
 Relay
 AC MOTOR
 ADVANTAGES
 APPLICATIONS
 WORKING PROCEDURE
 CONCLUSION

3. ABSTRACT
Irrigation is the key to a successful garden. Long
gone are the days of manual watering or relying on a
friend to water when you are on vacation or away on
business.
The Project presented here waters your plants
regularly when you are out for vocation. The circuit
comprises sensor parts built using op-amp IC
LM324. Op-amp is configured here as a comparator.

4. Two stiff copper wires are inserted in the soil to
sense the whether the Soil is wet or dry.
The comparator monitors the sensors and when
sensors sense the dry condition then the project will
switch on the motor and it will switch off the motor
when the sensors are in wet. The comparator does
the above job it receives the signals from the sensors.

5. BLOCK DIAGRAM

6. SOLAR CELL DESCRIPTION

7. The solar cell is composed of the semiconductors of
the P-N junctions.
It can convert light into electric energy. Therefore we
can assume that electricity produced using sunlight
shining on the solar cell can be used like common
electricity.

8. Lead Acid Battery
Specifications
12V 1.3Ah sealed lead acid battery
1. CE and RoHs
2. high quality and reliability
3. maintenance free
4. long life cycle
12V 1.3Ah sealed lead acid battery
General Features:
Sealed and maintenance free operation.
Non-Spillable construction design.
ABS containers and covers(UL94HB, UL94-
0)optional.
Safety valve installation for explosion proof.
High quality and high reliability.
Exceptional deep discharge recovery
performance.
Low self discharge characteristic.
Flexibility design for multiple install
positions.

9. POWER SUPPLY
 This project uses regulated 5V, 500mA power supply.
 7805 three terminal voltage regulator is used for voltage
regulation.
 Bridge type full wave rectifier is used to rectify the ac out
put of secondary of 230/12V step down transformer.

10. LM324
 The LM324 series consists of four independent, high gain,
internally frequency compensated operational amplifiers which
were designed specifically to operate from a single power
supply over a wide range of voltages
 Features
 Internally frequency compensated for unity gain
 Large DC voltage gain 100 dB
 Wide bandwidth (unity gain) 1 MHz (temperature
compensated)
 Wide power supply range: Single supply 3V to 32V or dual
supplies ±1.5V to ±16V
 Very low supply current drain (700 μA)—essentially
independent of supply voltage
 Low input biasing current 45 nA (temperature compensated)

11. PIN DIAGRAM

12. RELAYS
 A relay is an electrically controllable switch widely used in
industrial controls, automobiles and appliances.

13. AC MOTOR
An electric motor uses electrical energy to produce
mechanical energy
Electric motors are found in household appliances
such as fans, refrigerators, washing machines, pool
pumps, floor vacuums, and fan-forced ovens.

14. 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

15. APPLICATIONS
Roof Gardens
Lawns
Agriculture Lands
Home Gardens

16. WORKING PROCEDURE:
 Switch ON the power supply. Each and every module
require +5vdc of supply. In this project, we will be using
two metal plates and we will be inserting it into the soil
and sets some reference voltage. When ever the soil dry-
wet sensor voltage is less than the reference voltage then
that signals goes to LM324 Comparator.
 This comparator switches ON the water pump through
Relay automatically when the soil is DRY. To drive the
relay we are using transistor driver because relay requires
high current of 10 to 20 mile amps.
 And when the soil dry-wet sensor voltage is higher than
the reference voltage then that signals goes to LM324
Comparator.
 This comparator switches OFF the water pump through
Relay automatically when the soil is WET.
 So, in this way we are reducing the man power.

17. The project “Intelligent Automatic Plant
Irrigation System ” is designed, tested
and implemented successfully. It is
much easy and cost effective.
CONCLUSION