Swami Sachchidanand
Polytechnic College,
Visnagar
PREPARED BY: GUIDED BY:Dasrat. J. Maheshwari (Lecturer in E.E. dept. SSPC VIsnagar)
 GROUP - J :
1. Patel Tirth A.
(106500309052)
2. Raval Jayesh A.
(106500309037)
3. Rami Jay R.
(106500309061)
4. Sutariya Jitendra A.
(106500309054)
5. Sathwara Hardik S.
(106500309083)
1
A Project Report on
Automatic Fan Control And Intensity Control
By Using Microcontroller
DEVELOPED BY:PATEL TIRTH A.
(106500309052)
UNDER THE GUIDENCE OF
Internal Guide:Dasrat. J. Maheshwari
E.E. Dept., SSPC, VIsnagar
SUBMITTED TO:
Swami Sachchidanand Polytechnic College, Visnagar
GUJARAT TECHNOLOGICAL UNIVERSITY,AHMEDABAD
2
Swami Sachchidanand Polytechnic College, Visnagar
CERTIFICATE
TO WHOM SO EVER IT MAY CONSERN
This is to certify that project work embodied in this report entitled “Automatic
Fan Control And Intensity Control By Using Microcontroller” was carried out
by Group – J (Electrical Eng. Dept.) at Swami Sachchidanand Polytechnic
College Visnagar for partial fulfillment of Diploma Electrical Engineering
semester 6th to be awarded Gujarat Technological University. This project work
has been carried out under my supervision and is to my satisfaction.
Group Members
Enrollment No.
Patel Tirth A.
(106500309052)
Raval Jayesh A.
(106500309037)
Rami Jay R.
(106500309061)
Sutariya Jitendra A.
(106500309054)
Sathwara Hardik S.
(106500309083)
Date of Submission
Guide UDP
Head of Department
3
Automatic Fan Control
& Intensity Control by
using Microcontroller
4
ABSTRACT
This project will present the design, construction,
development, control and evaluation of an automatic
switching electric fan and also control the intensity of
light. The microcontroller based automatic fan system and
light systems presented in this project are required to
fulfill the requirement of technologies “tomorrow will be
more advanced than today”. The electric fan
automatically switches according to the environment
temperature changes and lights are switch on one by one
according to the room intensity changes. This electric
systems are contains combination of sensor, LDR,
controller and relay with integration of embedded
controlled programming. Finally, this system performance
will be evaluated by comparing performance data to the
theoretical.
5
INDEX
Chapter
No.
Contents
Page
No.
1
INTRODUCTION
7 to 9
2
LITERATURE REVIEW
10 to 27
3
CIRCUIT DIAGRAM
28 to 35
4
ADVANTAGES
36 to 37
5
REFERENCE
38 to 39
6
CHAPTER 1
INTRODUCTION
7
1.1 Project Background
Sometimes electric fan and light is wasting
power because of human attitude. Human also
mostly demands something that easily to be used without
wasting energy. To minimize or to reduce the power
usage, this project developed an automatic fan system
where fan is controlled by the room temperature and light
system where lights are controlled by room light intensity.
1.2 Problem Statement
Most human feels the inconvenient about
starting the fan manually when the room temperature
changes. So, the automatic fan system that automatically
switches on the fan according to temperature changes is
recommended to be built for solving this problem.
Most human feels the inconvenient about
switch on the light manually when the room light
intensity changes. So, the automatic light system that
automatically switches on the light according to intensity
changes is recommended to be built for solving this
problem.
8
1.3 Project Objectives
The objectives of this project are to:
i. Enable the electric fan to automatically switch
on-off according to temperature changes.
ii. Enable the light to automatically switch on-off
according to room intensity changes.
iii. Develop an automatic fan system and light
system that can preview the status of the
temperature and the intensity by using Liquid
Crystal Display (LCD).
1.4 Project Scopes
The system is built using:
i. Microcontroller as the main controller.
ii. The temperature sensor as the input for the
microcontroller.
iii. Relay as the output of microcontroller.
iv. LDR as the input for the microcontroller.
v. LCD as the preview the status of input.
9
CHAPTER 2
LITERATURE REVIEW
10
2.1 Introduction
This chapter reviews about previous system that
been developed and has similarities with the automatic
fan system and automatic light system plus the
components that will be used in developing this system.
2.2 ATmega8 microcontroller
The system is using ATmega8 as the
microcontroller. The temperature sensor senses the
temperature change and produces the output, the fan is
switched on to the range that been set.
There are two thresholds in the program, the
minimum temperature and the maximum temperature. “If
the temperature is below the minimum temperature
threshold, the fan will be turned off. If the temperature is
above the maximum temperature threshold, the fan is set
to its maximum speed.”
 Features
• High-performance, Low-power Atmel ®AVR® 8-bit
Microcontroller
11
• Advanced RISC Architecture
– 130 Powerful Instructions – Most Single-clock Cycle
Execution
– 32 × 8 General Purpose Working Registers
– Fully Static Operation
– Up to 16MIPS Throughput at 16MHz
– On-chip 2-cycle Multiplier
• High Endurance Non-volatile Memory segments
– 8Kbytes of In-System Self-programmable Flash
program memory
– 512Bytes EEPROM
– 1Kbyte Internal SRAM
– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM
– Data retention: 20 years at 85°C/100 years at 25°C(1)
– Optional Boot Code Section with Independent Lock
Bits In-System Programming by On-chip Boot Program
True Read-While-Write Operation
– Programming Lock for Software Security
• Peripheral Features
– One 16-bit Timer/Counter with Separate Rescale,
Compare Mode, and Capture Mode
– Real Time Counter with Separate Oscillator
– Three PWM Channels
– 8-channel ADC in TQFP and QFN/MLF package
Eight Channels 10-bit Accuracy
– 6-channel ADC in PDIP package Six Channels 10-bit
Accuracy
– Byte-oriented Two-wire Serial Interface
12
– Programmable Serial USART
– Master/Slave SPI Serial Interface
– Programmable Watchdog Timer with Separate On-chip
Oscillator
– On-chip Analog Comparator
• Special Microcontroller Features
– Power-on Reset and Programmable Brown-out
Detection
– Internal Calibrated RC Oscillator
– External and Internal Interrupt Sources
– Five Sleep Modes: Idle, ADC Noise Reduction, Powersave, Power-down, and Standby
• I/O and Packages
– 23 Programmable I/O Lines
– 28-lead PDIP, 32-lead TQFP, and 32-pad QFN/MLF
• Operating Voltages
– 2.7V - 5.5V (ATmega8L)
– 4.5V - 5.5V (ATmega8)
• Speed Grades
– 0 - 8MHz (ATmega8L)
– 0 - 16MHz (ATmega8)
• Power Consumption at 4Mhz, 3V, 25°C
– Active: 3.6mA
– Idle Mode: 1.0mA
– Power-down Mode: 0.5Μa
13
2.3 Liquid Crystal Displays
LCD Display (16*2)
Fig.2.1:LCD
Fig.2.2: Back view of LCD
14
Liquid Crystal Displays (LCD)
An LCD is a small low cost display. It is easy to interface
with a micro-controller because of an embedded
controller(the black blob on the back of the board). This
controller is standard across many displays (HD 44780)
which means many micro-controllers (including the
Arduino) have libraries that make displaying messages as
easy as a single line of code.
Fig.2.3
15
Testing
Testing your LCD with an Adriano is really simple. Wire
up your display using the schematic or breadboard layout
sheet. Then open the Adriano IDE and open the example
program.
2.4 Fan Controlling System
2.4.1 LM35 Precision Centigrade
Temperature Sensor
Following is the block diagram of LM35 Precision
Centigrade Temperature Sensor.
16
The LM35 series are precision
integrated-circuit temperature sensors, whose output
voltage is linearly proportional to the Celsius
(Centigrade) temperature. The LM35 thus has an
advantage over linear temperature sensors
calibrated in ° Kelvin, as the user is not required to
subtract a large constant voltage from its output to
obtain convenient Centigrade scaling. The LM35
does not require any external calibration or trimming
to provide typical accuracies of ±1⁄4°C at room
temperature and ±3⁄4°C over a full −55 to +150°C
Temperature range. Low cost is assured by trimming
and calibration at the wafer level. The LM35’s low
output impedance, linear output, and precise
inherent calibration make interfacing to readout or
control circuitry especially easy. It can be used with
single power supplies, or with plus and minus
supplies. As it draws only 60 μA from its supply, it
has very low self-heating, less than 0.1°C in still air.
The LM35 is rated to operate over a −55° to +150°C
temperature range, while the LM35C is rated for a
−40° to +110°C range (−10° with improved
accuracy). The LM35 series is available packaged in
hermetic TO-46 transistor packages, while the
LM35C, LM35CA, and LM35D are also available in
the plastic TO-92 transistor package. The LM35D is
also available in an 8-lead surface mount small
outline package and a plastic TO-220 package.
17
 Features
 Calibrated directly in ° Celsius (Centigrade)
 Linear + 10.0 mV/°C scale factor
 0.5°C accuracy guarantee able (at +25°C)
 Rated for full −55° to +150°C range
 Suitable for remote applications
 Low cost due to wafer-level trimming
 Operates from 4 to 30 volts
 Less than 60 μA current drain
 Low self-heating, 0.08°C in still air
 Nonlinearity only ±1⁄4°C typical
 Low impedance output, 0.1
for
mA load
1
18
2.4.2 ULN200 Liner Integrated Circuit
HIGH VOLTAGE AND HIGH CURRENT
DARLINGTON TRANSISTOR ARRAY
 DESCRIPTION
The ULN2003 is a monolithic high voltage
and high current Darlington transistor arrays. It consists
of seven NPN Darlington pairs that features highvoltage outputs with common-cathode clamp diode for
switching inductive loads. The collector-current rating
of a single Darlington pair is 500mA. The Darlington
pairs may be paralleled for higher current capability.
Applications include relay drivers, hammer drivers,
lamp drivers, display drivers (LED gas discharge), line
drivers, and logic buffers.
The ULN2003 has a 2.7kW series base
resistor for each Darlington pair for operation directly
with TTL or 5V CMOS devices.
19





FEATURES
500mA rated collector current (Single output)
High –voltage output: 50V
Inputs compatible with various types of logic.
Relay driver application.

LOGIC DIAGRAM
20
2.5 Light Controlling System
2.5.1 LDR
(Light Dependent Resistor)
Two cadmium sulphide (cds) photoconductive cells with
spectral responses similar to that of the human eye. The
cell resistance falls with increasing light intensity.
Applications include smoke detection, automatic lighting
control, and batch counting and burglar alarm systems.
21
 Applications
Photoconductive cells are used in many different
types of circuits and applications.
Analog Applications
 Camera Exposure Control
 Auto Slide Focus-dual cell
 Photocopy Machines-density of toner
 Colorimetric Test Equipment
 Densitometer
 Electronic Scales-dual cell
 Automatic Gain Control-modulated light
source
 Automated Rear View Mirror
Digital Applications
 Automatic Headlight Dimmer
 Night Light Control
 Oil Burner Flame Out
 Street Light Control
 Absence/ Presence
 Position Sensor
22
 Sensitivity
The sensitivity of a photo detector is the
relationship between the light falling on the device
and the resulting output signal. In the case of a
photocell, one is dealing with the relationship
between the incident light and the corresponding
resistance of the cell.
-
 Spectral
Response
23
Like the human eye, the relative sensitivity
of a photoconductive cell is dependent on the
wavelength
of
the
incident
light.
Each
photoconductor material type has its own unique
spectral response of the photocell versus wavelength
of light.
2.5.2 LED (Light Emitting Diode)

Introduction
A Light-Emitting Diode (LED) in essence is a
P-N junction solid-state semiconductor diode that emits
light when a current is applied though the device.[1] By
scientific definition, it is a solid-state device that controls
current without the deficiency of having heated filaments.
How does a LED work? White LEDs ordinarily need 3.6
Volts of Direct Current (DC) and use approximately 30
milliamps (mA) of current and has a power dissipation of
approximately 100 mill watts (mW). The positive power
is connected to one side of the LED semiconductor
through the anode and a whisker and the other side of the
24
Semiconductor is attached to the top of the anvil or the
negative power lead (cathode). It is the chemical
composition or makeup of the LED semiconductor that
determines the color of the light that the LED produces as
well as the intensity level. The epoxy resin enclosure
Allows most of the light to escape from the elements and
protects the LED making it virtually indestructible.
Furthermore, a light-emitting diode does not have any
moving parts, which makes the device extremely resistant
to damage due to vibration and shocks. These
characteristics make it ideal for purposes that demand
reliability and strength. LEDs therefore can be deemed
invulnerable to catastrophic failure when operated within
design parameters.
Figure shows a typical traditional indicator
LED. Traditional indicator LEDs utilize a small LED
semiconductor chip that is mounted on a reflector cup
also known as the anvil, on a lead-frame (whisker).This
whole configuration is encased in epoxy which also
serves the purpose of a lens. LEDs have very high thermal
resistance with upwards of 200K per Watt.
25

Principle & Mechanism
The essential portion of the Light Emitting
Diode is the semiconductor chip. Semiconductors can be
either intrinsic or extrinsic. Intrinsic semiconductors are
those in which the electrical behavior is based on the
electronic structure inherent to the pure material.[5] When
the electrical characteristics are dictated by impurity
atoms, the semiconductor is said to be extrinsic.[6] See
Appendix A for further information regarding the
different materials and their characteristics. This chip is
26
further divided into two parts or regions which are
separated by a boundary called a junction. The p-region is
dominated by positive electric charges (holes) and the nregion is dominated by negative electric charges
(electrons). The junction serves as a barrier to the flow of
the electrons between the p and the n-regions. This is
somewhat similar to the role of the band-gap because it
determines how much voltage is needed to be applied to
the semiconductor chip before the current can flow and
the electrons pass the junction into the p-region.
Fig.: Cross section of a typical semiconductor LED
showing the n and p-type semiconductor layers
27
CHAPTER 3
CIRCUIT DIAGRAM
AND
WORKING
28
3.1 AT mega8 Microcontroller
Fig.: 3.1: Microcontroller
29
3.2 Following is the full circuit diagram with
connection.
-
2 * 16 LCD
VCC
LED 1
LED 2
RESET
INC
PB6
PB7
PD5
PD6
PD7
PB0
PC5
PC4
PC3
PC2
PC1
PC0
GND
AREF
AVCC
PB5
PB4
PB3
PB2
PB1
28
27
26
25
24
23
22
21
20
2
DEC
VOUT
LM 35
VS+
1
3
9
10
11
12
13
14
PC6
PD0
PD1
PD2
PD3
PD4
VCC
GND
ATMEGA 8
1
2
3
4
5
6
7
8
LED 3
GND
LDR
19
18
17
16
15
3
4
RELAY
1
2
3
4
5
6
7
8
1B
2B
3B
4B
5B
6B
7B
ULN 2003
5
1C
2C
3C
4C
5C
6C
7C
GND COM
16
15
14
13
12
11
10
9
Fig.3.2: Circuit Diagram With Connection
30
 WORKING
This project controls the room light
intensity and room temperature. This project depends
on two main components. First is the LDR (Light
Dependant Resistance) and the second is the LM 35
Temperature sensor.
 Room Light Intensity Control

When the room light intensity value is less than
the 1st standard value which is set by push button
switches, the LDR give the signal to microcontroller.
Microcontroller switched on the supply of 3 LEDs.

When the room light intensity value is less than
the 2nd standard value, microcontroller switched on
the supply of 2 another LEDs.

When the room light intensity value is more than
2nd standard value, microcontroller switched off the
supply of 2 LEDs.
31

When room light intensity value is more then the
1st standard value, microcontroller switched off the
supply of 3 another LEDs.

This way, the room light intensity is controlled
by this project.
 Room Temperature control

When the room temperature value is getting high
from standard value, microcontroller switched on the
supply of Fan.

When the room temperature value is getting low
from standard value, microcontroller switched off the
supply of Fan.

This way, the room temperature is controlled by
this project.
32
3.3 Power Supply circuit
Fig.3.2: power supply circuit
This figure showed how to give the supply to this
circuit.
33
Our circuit needs 5v DC supply to operate. Therefore we
use power supply circuit.
This circuit includes following components……
1) Step-Down Transformer
2) 4 Diode (for make bridge rectifier)
3) 1 Capacitor (1000 microfarad)
4) 1 Capacitor (47 microfarad)
5) 7805 Voltage Regulated Circuit
We need step-down transformer so 230V AC
supply is given to step-down transformer.
Transformer gives us 12V AC. This 12V is given to
bridge rectifier for rectification. After rectification
we have 12V DC. This 12V DC has some AC
components so we use Capacitors. It connected in
parallel. It absorbs AC components from 12V DC.
Then this 12V pure DC is given to 7805 Regulated
Power Supply circuit. This circuit gives us 5V DC
for the supply of our main circuit.
34
Project Model
35
CHAPTER 4
Advantages
36
4.1 ADVANTAGES

Circuit is simpler in design.

We can use Solar panel as power supply.

The use of fan switch in fans can be avoided.

Power saving.

Temperature variations can be easily tracked down.

Less maintenance.

Easily repairable. Since there is no complex circuitry
setup involved.

Low installation cost.
37
CHAPTER 5
REFERENCE
38
Reference:1. www.google.co.in
2. www.national.com
3. www.electroniccircuit.net
4. www.microcontroller.net
39