1. 1
Greenhouse Automation System Using Cell Phone
Patel Jayprakash Shaileshkumar - 11669987
Faculty of Engineering and Technology
University of Technology, Sydney
Sydney, Australia
Jayprakash.S.Patel@uts.edu.au
Abstract - by undertaking this research based project, main
aim is to find out the best real time solution to automate the
greenhouse farming in terms of monitoring and controlling the
temperature and humidity inside the greenhouse. It can be
governed by using GSM/GPRS SIM900 module which is a
programmable device by having all the functionalities as any
GSM cell phone has. There is no need of skilled workers and
labors that is required for farming. All the required atmospheric
parameters such as humidity, temperature, heat level, light etc.
can be set by programming the micro-controller for the optimum
output and effective yield. Such parameters will be set to the
specific threshold limit which may vary crops to crops. If the
threshold level of any parameter crosses the pre-defined limit,
micro-controller will command the connected sub-systems such
as fogger, sprinkler, dripper, irrigation, heat lamp etcetera to
switch on or off depending on the required the parameters.
Micro-controller will transmit this information to the
GSM/GPRS SIM900 and GSM/GPRS SIM900 will send a
feedback in terms of text message. The design of this proto-type is
generic in such a manner that one can easily operate, control and
monitor multi-site of greenhouse farming. This system will use an
IP based camera, which will facilitate the live streaming of the
greenhouse to the cell phone of the authorized user.
Keywords - Greenhouse, Automation, GSM/GPRS SIM900,
Micro-controller, Sensors, Actuators.
1. INTRODUCTION
In this recent era, automation made a significant impact on
existing manual systems. In farming, automation techniques
still needs to be adopted. Automated greenhouse farming
technique is an innovative aspect in terms of yielding the
variety of crops in the off season by controlling the required
atmospheric parameters within the greenhouse. Greenhouse
farming is an important part of the agriculture in every country
as they can be used to grow plants under controlled climatic
conditions for the quality production. From last two decades,
the trend of manual greenhouse farming has been popularly
transformed towards automated greenhouse farming. This
system equipped with distinct hardware module called as a
sensors to sense the parameters within the greenhouse such as
humidity, temperature, heat level and light and further it is
transmitted to the micro-controller. The micro-controller
continuously monitors the digital data that has been sent from
sensor and compares it with the threshold limit which is
programmed in the micro-controller itself. It will command
installed sub-systems that is connected to micro-controller, via
actuators for the necessary actions to take place if value of the
parameters overcome the threshold limit. Actuators will switch
on and off to drive the AC sub-systems that are connected to
same micro-controller to maintain the required atmospheric
parameter level within the threshold limit. At first, this
information will be monitored by micro-controller and further
it will be transmitted to GSM/GPRS SIM900. The same
information will be sent to the authorized user by GSM/GPRS
SIM900 module as a feedback text message to notify the user
about the current situation of the greenhouse. An advanced
feature such as live monitoring of the greenhouse can be
enabled by using IP based camera which captures the live
feeding and broadcast it on a unique IP address. This generic
and cost effective pro-type architecture will bring green
revolution in the field of agricultural farming sector.
2. LITERATURE REVIEW
The complete solution for the automated greenhouse
system is to compare the current value of temperature and
humidity with the required value for the specific crop and if it
does not match, then give a command to actuators for driving
the sub-systems and required actions need to be performed.
(Omid 2004) proposed a computer based bulky semi-
automated greenhouse system which cannot be operated from
remote location. A skilled labor is required all the time to
monitor the greenhouse farming. (Reddy 2012) Discussed
about Bluetooth based greenhouse system which is capable of
operating in a specific restricted range, maximum of 30 meters.
(Kolhe & Annadate 2012) Developed a system using ARM 7
controller, which does not possess the compatibility to work
with binary digits on x86 bit architecture. (Khandelwal 2012)
Proposed a method to sense the temperature parameter using
thermostat sensor. But, there is no provision to sense the
humidity factor as every crop needs certain percentage of
humidity to grow. (Ai & Chen 2011) Implemented a
greenhouse environment system using the internet via team
viewer software to monitor the greenhouse while developing an
android application. (Sharma & Makwana 2013) Designed a
system by using thermostat sensor, GSM modem, actuators and
Atmega 16bit micro-controller. In this system, GSM modem
retrieves control flag from the sensor and Atmega micro-
controller receives the control flag from GSM modem. Control
flag continuously is being compared with the reference signal
and if it varies then micro-controller gives command to
actuators to take required actions according to the program
(Barash et al. 1980), which coded in to the micro-controller. To
overcome all the above real time problems, this system design

2. 2
associates with the following sub-systems in terms of sensor,
actuator, micro-controller, GSM/GPRS SIM900 module and
LCD display.
2.1 LDR: Light Dependent Resistor
LDR is the Light Dependent Resistor which is used for sensing
the level of the light in the greenhouse. When light strikes on
the surface of metallic film contact, the amount of resistance
gets vary depending upon the light intensity. LDR allows
current to pass through the circuit when there is an ambient
amount of light intensity strikes on the surface. LDR stops the
flow of current if there no required amount of light level.
Figure 2.1 Working Principle of LDR
Features: Simple design and low cost, Wide spectral response,
Fast response to the intensity of light, Hold up to (10^12) Ω
resistance
2.2 DHT22 Sensor
Digital Humidity and Temperature sensor integrated with the
capacitor and thermistor to sense the amount of the moisture in
the surrounding air and temperature level respectively. DHT22
sensor has digital data pin, hence there is no need of converting
analogue data into digital data.
Figure 2.2 DHT22 Pin Diagram
Features: (1) Range of humidity - 0% to 100%. (2) Range of
temperature: -40°C to +80°C. (3) Accuracy in the measurement
of humidity by ±2%. (4) Accuracy in the measurement of
temperature by ±0.5°C. (5)Range of operating voltage between
+3.3V to +6V maximum. (6) Maximum current capacity of
+2.5mA while data transferring. (7) Dimension - 27mm x
59mm x 13.5mm. (8) 4 pins with the spacing of 0.1". (9)
Digital data pin.
2.2.1 Working Principle of DHT22 Sensor
To the response of the MCU (micro-controller unit), DHT22
sensor sends data frame of 40 bits as shown in the figure 2.2.1.
First 2 byte represents binary data to calculate the percentage
of the humidity and following 2 byte represents binary data to
calculate the percentage of temperature. Last 1 byte of data
used for check sum and which is the summation of first 4 byte
of data. [Check Sum] = [0000 0010 + 1000 1100 + 0000 0001
+ 0101 1111] = [1110 1110]; [Humidity] = [0000 0010 1000
1100]/10 = [62.80%]; [Temperature] = [0000 0001 0101
1111]/10 = [35.1°C]. When the 1st bit of the 3rd byte is ‘1’,
then it dictates that temperature is in minus (below 0°C). For
example, if 3rd and 4th byte shows ‘1000 0000 0110 0101’,
then the temperature is ‘-10.10°C’.
Figure 2.2.1 Digital Data Frame of DHT22 Sensor
2.2.2 Interfacing of DHT22 sensor with micro-controller
MCU sends the request signal to the DHT22 sensor
periodically to measure the surrounding humidity and
temperature values. The time frame between the 20µs to 40µs,
DHT22 sends the response signal to the MCU followed by the
total of 40 bits of binary data. MCU will calculate the
percentage of the humidity and temperature on the basis of 40
bits data received on digital pin of DHT22 sensor.
Figure 2.2.2 Timing Diagram of DHT22 Sensor
2.3 16x2 LCD Display
16x2 LCD displays total of 32 characters, which has built-in
controller. It will display the digital value of humidity and
temperature from the DHT22 sensor, which will be calculated
by the micro-controller and will be display on 16x2 LCD.
Figure 2.3 Pin Diagram of 16x2 LCD

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Features: (1) Easily programmable. (2) Display of seven
segment. (3) Enables use of special characters. (4) Voltage
supply of +5V maximum. (5) Current supply of +3.0mA
maximum.
2.4 L2933D Motor Driving Circuit
L293D motor driving circuit facilitates the motor to drive in
both the direction as clockwise and anti-clockwise respectively,
which can be easily controlled by micro-controller. L293D
needs very low voltage in terms of operating voltage. Actuators
cannot be operated directly from the digital output pin of
micro-controller, hence L293D is required to drive the
actuators.
Figure 2.4 Pin Connection Diagram of L293D
Digital output pin of micro-controller is not capable enough to
drive the connected actuators. Due to this, L293D is the
solution to overcome the problem of driving the actuators.
L293D is the chip of 16 pins as shown in figure 2.4.1. It is
designed to control maximum of 2 DC motors where for each
motor, there is a separate 2 I/O pins. Motor can be driven in
either clockwise or anti-clockwise direct according to the input
given on the input pin as shown in the Table 2.4.
Motor A Motor B
Stop Low Low
Clockwise Low High
Anti-clockwise High Low
Stop High High
Table 2.4 Behavior of motors
Features: (1) In-built thermal protection due to use of 4 hybrid
bridge circuitry. (2) Operating voltage requirements of +4.5V
to +36V. (3) Operating range of temperature between 0°C to
70°C. (4) Facilitates 4 DC motors or 2 stepper motors or 2
servo motors. (5) 4 bi-directional DC motors with the variable
speed of 8 bits.
2.5 CM8870 DTMF Decoder
DTMF keypad generates unique dual tone multiple frequency
when any of the keypad button pressed. DTMF keypad
comprises of two group of frequencies, one is low group
frequency and second is high group frequency.
Figure 2.5 Connection Diagram of CM8870 DTMF
DTMF frequency is basically a combination of raw frequency
(low group frequency in Hz) and column frequency (high
group frequency in Hz) as shown in the Table 2.5.
Column
Row
1209
Hz
1336
Hz
1477
Hz
1663
Hz
697 Hz 1 2 3 A
770 Hz 4 5 6 B
852 Hz 7 8 9 C
941 Hz * 0 # D
Table 2.5 Dual Tone Multiple Frequency
Features: (1) DIP package with 18 pins. (2) Maximum power
consumption of 35mW. (3) Decodes DTMF in 4 bits of binary
digit. (4) TTL level output for direct connection to the micro-
controller. (5) Use as cell phone remote control. (6) Facilitates
Caller ID.
2.6 ATMega328 Arduino Micro-controller
Arduino is an open source hardware module which can be
configured with user friendly programming. It is used to
control the actuators and different motors by receiving the
inputs from the connected sensors.
Figure 2.6 Connection Pin Diagram of ATMega328

4. 4
It uses stand-alone programming language and operated on the
computer regardless of operating system. Arduino software
uses programming language which is scripted in Java language.
It can be easily compiled and uploaded on the board with the
single click. It has an in-built C/C++ library with two most
common functions.
(1) Setup () – to initialize the program.
(2) Loop () – to run a program in a loop mode until board
resets.
Features: (1) Large database of in-built libraries. (2) User
friendly programming environment. (3) Open source software
platform. (4) Facilitates serial port debugging. (5) Supports
master-slave configuration. (6) Operating voltage range +5 V.
(7) 14 Digital I/O pins. (8) 32KB In-built flash memory.
2.7 GSM/GPRS SIM900
GSM/GPRS SIM900 is Quad-band module which can operate
on any of 850/900/1800/1900 MHz and facilitates all the GSM
services of call, SMS, packet data and fax with the benefit of
low power consumption. Due to its compact design, small
dimensions and light weight, it can be easily mounted on the
board. GSM/GPRS SIM900 module is capable of coding,
decoding, sending and receiving information to and from.
Figure 2.7 Pin Diagram of GSM/GPRS SIM900
Features: (1) Operates on Quad Band 850/900/1800/1900
MHz. (2) Class 4 (2W @850/900 MHz). (3) Class 1 (1W
@1800/1900 MHz). (4) Control via AT commands. (5) Low
power consumption in sleep mode – 1.5mA. (6) Operating
range of temperature: -40°C to +80°C. (7) Dimension - 24mm
x 24mm x 3 mm. (8) Facilitate in-built SIM application toolkit.
3. SYSTEM DESIGN
The prototype of system consists of LDR sensor, DHT22
sensor, 16x2 LCD display, CM8870 DTMF Decoder,
Atmega328 Arduino micro-controller and GSM/GPRS SIM900
module. Generic architecture of the prototype needs to be
integrated on a single board to design fully automated
greenhouse system.
3.1 Interfacing of sub-system hardware modules
LDR sensor, DHT22 sensor and 16x2 LCD display are
connected to the I/O pins of the Arduino micro-controller,
which is programmed with the code to take the appropriate
actions when the value of the parameters crosses its threshold
limit. After the data obtained from the LDR and DHT22
sensors, micro-controller compares this data with the required
reference values of the parameter stored in the program. If the
sensed value vary with the reference value, then micro-
controller commands the connected actuators sprinkler,
irrigation, dripper, fogger and light, heat lamp etcetera to
maintain the temperature, humidity, light and heat level inside
the greenhouse via L293D motor driving circuit as shown in
figure 3.1.
Figure 3.1 Interfacing of Sub-System Modules
3.2 Overall System Design
Reference value of the required parameters will be set in the
micro-controller for the specific crop. DHT22 sensor senses the
temperature and humidity periodically depending on the
programming coded in the micro-controller. Digital pin of
DHT22 sensor transmits data to the micro-controller. Micro-
controller compares received data with the threshold reference
value and takes the decision to control and automate the
greenhouse if required.
The design of the system is generic as it can operate either by
simple cell phone or smart cell phone. In case of simple cell
phone, only authorized user calls to the GSM/GPRS SIM900
module. GSM/GPRS SIM900 receives the call on automatic
answer mode and depending on the button pressed by the user,
unique dual tone multiple frequency tone generates by the
keypad. CM8870 DTMF decoder decodes the DTMF signal
frequency and converts it into the equivalent 4 bit binary digit
code. Micro-controller uses 4 bit binary code as an input and
depending on the combination of the bits programmed in the
micro-controller, micro-controller commands relays to drive
the actuators. (Wasi-ur-Rahman et al. 2009) Feedback message
about the current situation of greenhouse sends to authorized
user via GSM/GPRS SIM900 module.

5. 5
In the second case with the smart phone, (Dursun & Ozden
2011) android application comprises datasheet for the variety
of crops with all the required atmospheric parameters with its
threshold limit. User needs to select the crop in the application,
which has already set values for the temperature, humidity,
amount of light and heat level etcetera. The SMS sends to the
GSM/GPRS SIM900 at the greenhouse to automate the system.
In the first phase, users authenticate themselves in terms of
login and password. GSM/GPRS SIM900 module receives the
SMS and it further transmits the received message to the
micro-controller for decoding purpose. Micro-controller
decoded the message and compares it with the reference
message programmed in the micro-controller. Depending upon
the reference values for the parameters, micro-controller
commands motor driver circuit to operate the connected
actuators and relays to automate the greenhouse system from
the remote location. Simultaneously, user controls and
monitors the connected sub-systems drip irrigation, sprinkler,
fogger, heat lamps and lights etcetera. Internet protocol based
camera at the greenhouse feeds the live coverage of the system
on the unique IP address, which links to the same android
application of the greenhouse system.
Figure 3.2 Overall System Design
4. SIMULATION
Analog to digital convertor is not required as Arduino
micro-controller incorporates with 14 digital I/O pins. DHT22
and LDR sensor continuously sense the temperature, humidity
and amount of light within the greenhouse. As DHT22 sensor
senses the data digitally on its pin number 2 and further
forwards to the micro-controller as an input. Micro-controller
compares sensed data with reference data and according to the
coding scripted, micro-controller commands the actuators to
switch on and off using motor driver circuit.
NO YES
YES
YES
YES NO
YES
YES
Start
Android Application – User needs
to select the crop from the available
data sheet.
Message with specific atmospheric
requirement sent to the GSM/GPRS
SIM900.
Arduino MEGA compares received message
with the programmed reference message using
connected LDR and DHT22 sensors.
LM293D operates electronic valves of actuators
to maintain and automate the required
atmospheric parameters.
Arduino MEGA sends feedback message to the
authorized user either to notify.
Android Application
Login & Password
Live streaming on android
application using IP camera
Stop
Figure 4.0 Simulation Chart
5. CONCLUSION
In this project, system design is composed with the two
sensing devices LDR and DHT22 sensor, which senses light,
temperature and humidity on a pre-defined periodic intervals.
User sends a message to GSM/GPRS SIM900 module while
selecting a specific crop from the available list in the android
application. ATMega-328 micro-controller compares threshold
values with the sensed values that is measured by the sensors.
Micro-controller continuously monitors the required
parameters and commands actuators to switch on and/or off,
depending on the required action. Feedback message sent to the
authenticated user in terms of current state of actuator, current
value of temperature and humidity, and current level of light
and heat. Additionally, user can monitors live streaming of
greenhouse by using IP camera which can be accessed on a
static IP address. Overall, system can be completely monitored,
controlled and automated with this system design. It
incorporates security and privacy procedures that allow access
to the authenticated users only, while facilitating reliable and
precise automated system. Vision of this project is to contribute
towards the farming community by facilitating most advanced
farming technology that is cost effective, reduce labors and
increase the quality of product.

6. 6
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