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VSRD-IJEECE, Vol. 2 (6), 2012, 337-345

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1,2,3,4Research Scholar, Department of Electronics & Instrumentation Engineering, Galgotia College of Engineering & Technology, G.Noida, Uttar Pradesh, INDIA. *Correspondence : mittal.galgotia@gmail.com

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Green House Monitor and Control Using Wireless System Network

1Manish Mittal*, 2Gaurav Tripathi, 3Deepa Chauhan and 4Atul Agarwal

ABSTRACT

The hardware design is an embedded system which will closely monitor and control the climate parameters:

humidity, temperature, soil moisture, light of a greenhouse on a regular basis round the clock for cultivation of

crops or specific plant species which could maximize their production. The system comprises of sensor, ADC,

microcontroller and actuators. When any of the above mentioned climatic parameters cross a safety threshold

which has to be maintained to protect the crops, the sensors sense the change and the microcontroller reads this

from the data at its input ports after being converted to a digital form by the ADC. The microcontroller then

performs the needed actions by employing relays until the strayed-out parameter has been brought back to its

optimum level. A microcontroller is used as the heart of the system; it makes the set-up low-cost and effective

nevertheless. The program implements the Control Algorithms, sending control signals to the smart sensors in

order to reach the desired conditions. As the system also employs an LCD display for continuously alerting the

user about the condition inside the greenhouse, the entire set-up becomes user friendly.

Keywords : WSN, Embedded System, MCU.

1. INTRODUCTION

Many research and projects have been done in order to improve the conditions and cultivation of crops under

greenhouse. Often it is necessary to develop a control system to implement these studies. Wireless sensor

networks (WSN) have recently received a lot of attention in research community because of their continuous

advancement. A greenhouse is a structure with different types of covering materials, like glass or plastic roof

and frequently glass or plastic walls; it heats up because incoming visible solar radiation from the sun is

absorbed by plants, soil, and other things inside the building. Glass is transparent to this radiation. The warmed

structures and plants inside the greenhouse re-radiate this energy in the infra-red, to which glass is partly

opaque, and that energy is trapped inside the glasshouse. Although there is some heat loss due to conduction,

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there is a net increase in energy (and therefore temperature) inside the greenhouse. Air warmed by the heat from

hot interior surfaces is retained in the building by the roof and wall. These structures range in size from small

sheds to very large buildings. The greenhouses are filled with equipment like screening installations, heating,

cooling, and lighting and may be automatically controlled.

2. DESIGN OF GREENHOUSE CONTROL & MONITOR

An embedded system is designed based on measuring of parameters like humidity, temperature, soil moisture,

light intensity using a MCU AT89S52 which we can display using a LCD display. Design part consists of

hardware and software.

2.1.Hardware Description

To design hardware for green house monitoring various sensors are used to control the environment. The

parameters like green house temperature, humidity, light intensity for green house and soil wetness for crop

growth.

The green House monitoring system consists of sensor circuits, AT89S52 microcontroller, LCD module to

display the parameters, ADC and DAC, receiver and transmitter, and a required power supply unit. The

output of the sensors are given has input to the micro controller to control, display the parameters and

update the owner. Any parameter changing with set parameter for green house systems, the micro controller

will read and stores periodically.

Fig. 1 : Schematic Showing the Green House Monitoring

2.2. Software Description

The software includes the reading of various measurements from sensors, converting analog to digital values,

displaying in the LCD module and updating the user by sending the message for monitoring the green house

The microcontroller AT89S52 is used to do the A/D conversions, display the parameters and updating the

user.

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3. AT89S52 MICROCONTROLLER

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system

programmable Flash memory. The on-chip Flash allows the program memory to be reprogrammed in-system or

by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with in-system

programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller which provides a

highly-flexible and cost effective solution to many embedded control applications. In addition, the AT89S52 is

designed with static logic for operation down to zero frequency. The microcontroller used in the green house

monitoring system is AT89S52. It is used to read the various parameters and holds the monitoring program. It

receives the analog voltage signal coming from the sensors. After the conversion into digital signal it checks

weather the sensed data is in the set parameters. If the data does not comes under the set parameters the

microcontroller and shows the data on LCD screen. The various parameters reading program, A/D conversion

program and sending SMS program is done in assembly language.

Fig. 2 : AT89S52 Microcontroller

4. SENSORS

4.1. Temperature Sensor

National Semiconductors LM35 IC has been used for sensing the temperature. It is an integrated circuit sensor

that can be used to measure temperature with an electrical output proportional to the temperature (in C). The

temperature can be measured more accurately with it than using a thermistor. The sensor circuitry is sealed and

not subject to oxidation, etc. The converter provides accurately linear and directly proportional output signal

in millivolts over the temperature range of 0C to 155C. It develops an output voltage of 10 mV per

degree centigrade change in the ambient temperature. Therefore the output voltage varies from 0 mV at 0C to

1V at 100C and any voltage measurement circuit connected across the output pins can read the temperature

directly.

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Fig. 3 : Schematic for Temperature Sensor

4.2. Humidity Sensor

The humidity sensor HIH4000, manufactured by Honeywell is used for sensing the humidity. It delivers

instrumentation quality RH (Relative Humidity) sensing performance in a low cost, solderable SIP (Single In-

line Package). Relative humidity is a measure, in percentage of the vapour in the air compared to the total

amount of vapour that could be held in the air at a given temperature. The sensor develops a linear voltage vs.

RH output that is ratio metric to the supply voltage. That is, when the supply voltage varies, the sensor output

voltage follows in the same proportion. It can operate over a 4-5.8 supply voltage range. At 5V supply voltage,

and room temperature, the output voltage ranges from 0.8 to 3.9V as the humidity varies from 0% to 100%. The

voltage is converted to the digital form by the ADC and then sent as input to the microcontroller which reads the

data.

Fig. 4 : Schematic for Humidity Sensor

4.3. Soil Moisture

A simple humidity sensor (a humidity probe) can be constructed using two copper strips placed as close as

possible to each other, but no touching. A simple humidity sensor (a humidity probe) can be constructed using

two copper strips placed as close as possible to each other, but no touching. This sensor is based on the fact that

water is not pure water which is non conductor, but it is impure which is slightly conductor. Water sensor is

nothing but a series of very close PCB tracks. In normal mode these tracks are not conducting, but when some

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water fall on these tracks these line slightly start conducting and some positive voltage is available at the base of

transistor So NPN transistor is on and NPN transistor provide a negative voltage as a pulse to the

microcontroller.

Fig. 5 : Schematic for Soil Wet Sensor

4.4. Light Intensity Sensor

A simple light intensity sensor can be constructed using light depended resistance (LDR). This simple circuit

can be used to make your simple light intensity detector. The LDR light sensor is used to sense intensity of

light. In the light sensor we use IC LM358 as a main component. Pin no 8 is connected to the positive supply.

Pin no 4 is connected to the negative voltage. One capacitor is grounded from the pin no 3 for noise

cancellation. Output is available on the pin no 1. Sensor is connected to the pin no 3. In case of high intensity of

light LDR is all most shorted so LM 358 gives 5v as soon as light intensity decreases voltage output of LM358

decreases up to 0v. The voltage is inputted to the transistor. By selecting value of variable resister we can

activate transistor at required intensity of light to drive microcontroller by supplying negative pulse.

Fig. 6 : Schematic for Light Intensity Sensor

5. LCD DISPLAY

The display section consists of 16*2 LCD, which used to display Summary of IC being Inserted and result of

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test being conducted. LCDs can add a lot to your application in terms of providing a useful interface for the

user, debugging an application or just giving it a "professional" look. The most common type of LCD controller

is the Hitachi 44780 which provides a relatively simple interface between a processor and an LCD. The LCD

interface is a parallel bus, allowing simple and fast reading/writing of data to and from the LCD.

This waveform will write an ASCII Byte out to the LCD's screen. The ASCII code to be displayed is eight bits

long and is sent to the LCD either four or eight bits at a time. If four bit mode is used, two "nibbles" of data

(Sent high four bits and then low four bits with an "E" Clock pulse with each nibble) are sent to make up a full

eight bit transfer. The "E" Clock is used to initiate the data transfer.

Fig. 7 : LCD

6. ANALOG TO DIGITAL CONVERTER

The ADC0809 data acquisition component is a monolithic CMOS device with an 8-bit analog -to- digital

converter, 8-channel multiplexer and microprocessor compatible control logic. The 8-bit A/D converter uses

successive approximation as the conversion technique. The converter features a high impedance chopper

stabilized comparator, a 256R voltage divider with analog switch tree and a successive approximation register.

The 8 channel multiplexer can directly access any of 8-single-ended analog signals. The clock for the ADC is

generated using the IC 4083, which is a 2-input Schmitt triggered NAND gate. A Schmitt trigger is a

comparator circuit that incorporates positive feedback. The Control pin is pulled high and the capacitor charges

and discharges producing alternate patterns of 0s and 1, generating a square waveform. When the input is

higher than a certain chosen threshold, the output is high; when the input is below another (lower) chosen

threshold, the output is low; when the input is between the two, the output retains its value.

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Fig. 8 : ADC Circuitry

7. IMPLEMENTATION OF GREEN HOUSE MONITORING SYSTEMS

7.1. Software Implementation

In the software implementation part we had develop assembly code for measuring temperature, water pH value,

humidity, soil wetness, light intensity, display the parameters in LCD module, serial communication and to send

message to mobile receiver.

7.2. Hardware Implementation

In the hardware implementation part we had assembled, soldered the required components in general purpose

printed circuit board and made connection. We could provide a power supply of +5V DC for Micro controller,

+12V DC for sensor circuits. Finally we had made connection of temperature sensor circuit, pH measure sensor

circuit, humidity sensor circuit; soil wet sensor circuit, light intensity sensor circuit, GSM modem thru serial

communication cable to the AT89S52 micro controller.

Fig. 9 : Complete Hardware

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Fig. 10 : Transmitter and Receiver

8. RESULTS

After the feasible results obtained from the simulation, real time implementation of the green house monitoring

program is done. A hardware kit has been developed and put it on the green house environment. The kit consists

of a power supply unit, various sensors, microcontroller and an ADC. The output from the sensors is

continuously given to the microcontroller. Simultaneously the display is reading in LCD module. In the real

application the entire kit it is fixed on the green house system. When the parameters like temperature, pH,

humidity, soil wetness and light intensity are varied from set parameters, which is continuously monitored and

updated in the mobile receiver.

9. CONCLUSION

A step-by-step approach in designing the microcontroller based system for measurement and control of the four

essential parameters for plant growth, i.e. temperature, humidity, soil moisture, and light intensity, has been

followed. The results obtained from the measurement have shown that the system performance is quite reliable

and accurate.

The system has successfully overcome quite a few shortcomings of the existing systems by reducing the power

consumption, maintenance and complexity, at the same time providing a flexible and precise form of

maintaining the environment. The continuously decreasing costs of hardware and software, the wider acceptance

of electronic systems in agriculture, and an emerging agricultural control system industry in several areas of

agricultural production, will result in reliable control systems that will address several aspects of quality and

quantity of production. Further improvements will be made as less expensive and more reliable sensors are

developed for use in agricultural production. Although the enhancements mentioned in the previous chapter may

seem far in the future, the required technology and components are available, many such systems have been

independently developed, or are at least tested at a prototype level. Also, integration of all these technologies is

not a daunting task and can be successfully carried out.

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