Raj Kumar Goel Institute Of Technology

Presented by:- Sudhanshu Tripathi

Varun Gupta Shivam Tripathi

Anurag Singh

“Wireless Greenhouse Environment Monitoring through Sensors”

A Presentation

on

(EEE Department)

Wireless Greenhouse Environment Monitoring

through Sensors

Micro Controller

Soil moisture Sensor

Humidity Sensor

Temperature Sensor

Light sensor

Sprayer

Water Pump

Encoder HT12E

AC

O U T P U T D R I V E R

Light

16*2 LCD

RF Transmitter

RF Receiver

DECODER HT12D

Parts: 

Sensors (Data acquisition system)

Temperature sensor (LM35)

Humidity sensor (HIH4000)

Light sensor (LDR)

Moisture sensor

Microcontroller (AT89C52)

Liquid Crystal Display (Hitachi's HD44780)

Actuators – Relays

Devices controlled :

Water Pump (simulated as a bulb)

Sprayer (simulated as a bulb)

Cooler (simulated as a fan)

Artificial Lights (simulated as 2 bulbs)

Sensors:

This part of the system consists of various sensors, namely soil moisture, humidity,

temperature and light. These sensors sense various parameters- temperature, humidity,

soil moisture and light intensity and are then sent to the Analog to Digital Converter.

Microcontroller:

The microcontroller is the heart of the proposed embedded system. It constantly

monitors the digitized parameters of the various sensors and verifies them with the

predefined threshold values and checks if any corrective action is to be taken for the

condition at that instant of time. In case such a situation arises, it activates the

actuators to perform a controlled operation.

Display Unit:

A Liquid crystal display is used to indicate the present status of parameters and the

respective AC devises (simulated using bulbs). The information is displayed in two

modes which can be selected using a push button switch which toggles between the

modes. Any display can be interfaced to the system with respective changes in

driver circuitry and code

Working: 

Power supply: The power supply section consists of step down transformers of

230V primary to 12V secondary voltages for the +5V power supplies respectively.

The stepped down voltage is then rectified by 4 1N4007 diodes. The high value of

capacitor 1000 µF charges at a slow rate as the time constant is low, and once the

capacitor charges there is no resistor for capacitor to discharge. This gives a constant

value of DC. IC 7805 is used for regulated supply of +5 volts in order to prevent the

circuit ahead from any fluctuations. The filter capacitors connected after this IC

filters the high frequency spikes.

If internal power dissipation becomes too high for the heat sinking provided, the

thermal shutdown circuit takes over preventing the IC from overheating.

Temperature sensor:

A temperature sensor (LM35DZ) can measure from 0°C to 100°C. However, the

output is 0V at 2°C. Hence the measurable temperature is above 2°C. The output of a

sensor goes up by 10mV for every 0°C. The output voltage in 32°C is 300mV.

The output voltage of a sensor is amplified by an operational amplifier, and is

inputted into the base of transistor .The temperature sensitivity adjusting the gain of

an operational amplifier by VR.

So in the normal mode when temperature is below 60C the output or LM358 is not

sufficient to drive transistor BC 548. When temperature raises above 60C the output

of LM358 is about 3V which is sufficient to drive transistor thus microcontroller get

positive voltage.

Soil moisture sensor: 

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 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.

Humidity sensor:

The humidity sensor SYS-1used 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 vapor that could be held in the air

at a given temperature.

Features:

• Linear voltage output vs. %RH

• Laser trimmed interchangeability

• Low power design

• High accuracy

• Fast response time

• Stable, low drift performance

• Chemically resistant

• The RH sensor is a laser trimmed, thermoset polymer capacitive sensing element

with on-chip integrated signal conditioning.

Light intensity sensor:

The light intensity in the green house is sensed by a photo sensor and a signal in the

form of voltage is sent to the microcontroller. This signal is scaled in such a way that

5V is generated in the day lit environment. The lamp is dimmed based on this signal.

A photo sensor is a complete assembly that includes the optical arrangement and

electronic circuitry that is coupled to an electronic component called a photocell. A

photocell is a light responding silicon chip that converts incident radiant energy into an

electrical signal. Photo sensor includes a diffuser or lens that collects light and an

optical filter that rejects the UV and IR spectra. The electronic circuitry amplifies the

dc voltage generated by the photocell, and after comparing it with a reference voltage,

sends an appropriate signal to the control device.

Microcontroller:

The PIC family of microcontrollers is based on an architecture which is highly

optimized for embedded control systems. It is used in a wide variety of applications

from military equipment to automobiles to the keyboard. The manufacturers have

added numerous features and peripherals to the PIC such as I2C interfaces, analog to

digital converters, watchdog timers, and pulse width modulated outputs. Variations of

the PIC with clock speeds up to 40MHz and voltage requirements down to 1.5 volts

are available. This wide range of parts based on one core makes the 8051 family an

excellent choice as the base architecture for a company's entire line of products since it

can perform many functions and developers will only have to learn this one platform.

The 16f877a is a low-power, high-performance CMOS 8-bit microcontroller with

8K bytes of in-system programmable Flash memory. The device is manufactured

using Microchip high-density nonvolatile memory technology and is compatible

with the industry standard

PIC 16f877a provides a highly-flexible and cost effective solution to embedded

control applications. In addition, the 16f877a is designed with static logic for

operation down to zero frequency and supports two software selectable power

saving modes. The Idle Mode stops the CPU while allowing the RAM,

timer/counters, serial port, and interrupt system to continue functioning. The

Power-down mode saves the RAM con-tents but freezes the oscillator, disabling

all other chip functions until the next interrupt or hardware reset.

Display section:

The display section consists of 16*2 LCD, which used to display Summary of IC

being Inserted and result of test being conducted.

LCDs can add a lot to your application in terms of providing an 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.

Thank You