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www.iaard.net IAARD Journals eISSN: 2455-3204
International Journal of Computer
Science and Information Technology International Journal of Computer Science and Information Technology, 2016, 2(1),8-11
T.Chockalingam et al., Page No.8
Temperature based dc fan speed control system using microcontroller and pulse
width modulation technique using PIC16F877A
T.Chockalingam 1,
Melese Yemane1and A.Agasthian
2
1Ambo University, Ambo, Ethiopia
2Network Administrator, Annauniversity, Thoothukudi Campus, India
………………………………………………………………………………………………………………………………………………………
ABSTARCT: Temperature based dc fan speed control system using microcontroller and pulse width modulation technique
using PIC16F877A is to control the speed of dc fan speed based on room temperature using pulse width modulation technique
with microcontroller. The temperature is read from the temperature feeler and the situation is checked depending on
temperature rate. The aim of developing this project is to control the speed of DC fan motor. The main advantage in using a DC
fan motor is that the s p e e d -Torque relationship can be varied to almost any useful form. To achieve the speed control an
electronic technique called Pulse Width Modulation is used which generates High and Low pulses. These pulses vary the speed
in the motor. For the generation of these pulses a microcontroller (PIC 16F877A) is used. As a microcontroller is used setting
the speed ranges as per the condition is easy which is done by changing the duty cycles time period in the program. This project
is practical and highly feasible in economic point of view, and has an advantage of running motors of higher ratings. This
project gives a reliable, strong, exact and efficient way of speed control of a DC fan motor. The simulation of the system has
been done on Proteus Professional Software v 8.1. Hardware implementation has been also done. The results of the research
and Output waveforms have been investigated.
Keywords: Microcontroller, temperature sensor, analog to digital converter, DC Fan, pulse width modulation and speed
control.
……………………………………………………………………………………………………………………………………
1. Introduction
The aim of this project is to control the speed of dc
fan speed based on temperature using pulse width modulation
technique with microcontroller. To get rid of the problem of
Obscurity to control temperature in industries, public
building, apartment house and private house a
microcontroller based controller has been proposed.
A temperature sensor has been used to measure the
temperature of the room and the speed of the fan is varied
according to the room temperature using pulse width
modulation technique. Controller is used to control the speed
of DC Fan and temperature is varied through the
Temperature sensor and data is sent to PIC 16F877A
microcontroller using analog to digital converter. The duty
cycle has been varied from 0 to 100% to control the fan
speed depending up on the room temperature, which is
displayed on liquid crystal display. Duty cycle values
between 20% and 90% allow smooth control of the fan.
Out of various control techniques available only two of them
can be used to control DC motor. They are sensor control and
sensor less control. With the improvement in machinery,
smart systems are being introduced every day. In the present
time microcontrollers play a vital role in the development of
the smart systems.
It is to be noted that dc motor is not directly
connected with microcontroller because a micro controller
can’t supply the current for the working of DC motor.
An independent control system which responses on the
ambience conditions. The idea behind this project is to
control the speed of DC fan using microcontroller based on
variation in temperature. Temperature controlled fan is an
alternative way to deal with the speed of the motor.
Temperature control is a process in which the
temperature of an object is measured and the passage of heat
energy into or out of the object is adjusted to achieve a
desired temperature. This project presents the interfacing of
temperature sensor with microcontroller by means of analog
to digital convertor, to display the temperature on a 16x2
LCD and to rotate a DC motor at different speeds at various
temperatures.
The pulse width modulation speed control function
is a function that externally controls the rotation speed of the
fan by changing the duty cycle of the input pulse signal
between the control terminal and GND.
Figure1.1 block diagram
International Journal of Computer Science and Information Technology, 2016, 2(1),8-11
T.Chockalingam et al., Page No.9
2. PROBLEM STATMENT
Statement of Problem
As the system is microprocessor based system, it has more
automated control over different operations. So it reduces the
communication of human with the system for those
operations such as controlling a fan for room temperature
.This project helps the user of the library to have a moderate
environment inside the library with a room temperature.
2.1 Objective
The objective of these project can be seen in two direction
based on main and supportive application of our design.
2.2 General Objective
The main aim of this document is to save energy
through the projected method. The power
consumption is reduced.
To control temperature variation using dc fan speed
control system.
2.3 Specific Objective
It is creation the library stylish by controlling,
temperature using a single microcontroller.
To solve a room temperature problem and find the
way to simplifies people’s life safety
To controls the rotation speed of the fan by
changing the duty cycle of the input pulse signal.
3. Methodology
The methodology we have followed during the development
of this project which starts from project title selection up to
the complete project submission is presented in this section.
First we did appropriately select the project title. After a
topic has been selected, additional discussions were done in
order to understand the concept and objective of the project.
Then, literature review was done and the background of this
project was studied by referring to various sources such as
reference books, internet, lecture notes and data sheets.
Figure 3.1 the Work Flow of the Project
In this project we have to analysis, design, select an
optimum or suitable materials and simulation of temperature
based dc fan speed control using microcontroller and pulse
width modulation technique. Firstly, Chips would be made to
be installed on the dc fan speed control system. These chips
will consist of a micro-controller along with temperature
sensors.
Figure 2.1 showed the methodology or work flow
for the project which is involving system development from
hardware and software to the integration of both elements.
Then, the system is being tested to produce a certain results
that will be analyzed to produce the results that compatible
with the system.
3.1.HARDWARE BLOCK DIAGRAM
Figure 3.2 Block Diagram of Simple System Design for a
temperature based dc Fan System
3.2 IMPLEMENTATION
1. The output pin of LM35 temperature sensor was connected
to one of the ADC input pin of PIC16F877A microcontroller.
2. LCD was connected to the microcontroller.
3. ADC was activated for interfacing the temperature sensor
and a program is written so that whatever temperature the
sensor senses it can be displayed on LCD screen.
4. Either electric AC bulb or soldering iron is used to heat the
temperature sensor.
5. Electric motor driver L293D is connected to
microcontroller.
6. DC motor is connected to the output of motor driver pin.
3.3 Schematic Diagram
Figure3.3 Schematic diagram
International Journal of Computer Science and Information Technology, 2016, 2(1),8-11
T.Chockalingam et al., Page No.10
Figure 3.4 flow chart
4. WORKING PRINCIPLE
The project uses a accuracy centigrade temperature sensor
LM35 which is capable of sensing the temperature. It gives
the output in mill volts. This output is converted into
corresponding digit data using inbuilt ADC of the PIC 16F
877A microcontroller. LCD is interfaced with the
microcontroller & the value of the actual temperature is
displayed on the LCD. The LCD displays the present
temperature. Also speed of the DC motor either increased or
decreased depends on the input temperature. The electric
soldering iron or electric bulb is used to differ the input
temperature.
5. Software procedures
The following software’s were used for programming and
feeding in PIC16f877A
1. Proteus 8.1 used to simulate the schematic diagram and
check the performance.
2. CCS compiler used to compile the program and generate
the Hex code.
6. HARDWARE OF THE PROJECT
Figure 6.1 Hardware Implementation
7.Discussion on Result
The speed of the fan has been controlled using PWM
technique according to the room temperature. The simulation
of the system has been done on Proteus Professional v 8.0
software packages and it is running in good agreement. The
logic used in the system is verified and shown in the
flowchart form. The duty cycle has been varied according to
room temperature and speed of the fan was controlled
accordingly. The accuracy of the system was validated. The
design of the system presented in this paper is appropriate
according to the modern technology.
TEMP AT 310C
As Figure bellow shows Pulse for temperature at 31℃. There
is variation in pulse at the same time fan speed is slow
Figure7.1 Pulse for temperature at31 ℃
TEMP 370C
TEMP 49
0C
TEMP 80
0C
International Journal of Computer Science and Information Technology, 2016, 2(1),8-11
T.Chockalingam et al., Page No.11
TEMP 100
0C
8.RESULTS AND CONCLUSION
8.1 Results
The project “Temperature based DC Fan Speed Control
System using Microcontroller and Pulse Width Modulation
Technique using PIC 16F877A” has been successfully
designed and tested. It is fairly clear from the above
argument that Speed Control of DC fan motor using
microcontroller by using PWM may be a complete system
that controls the speed of a motor by giving instructions to
the microcontroller to reduce the manual effort. The
technology saves money too and gives a return on
investment. This system have a great deal in common with
one another, 12V is used in this process of speed control of
dc motor. Execution of this process is easy. So by using
micro controller we control the speed of a DC fan motor
using L293D Motor driver IC. By applying a PWM pulse to
L293D, the speed of the motor varies .We used an LCD for
displaying the varying temperature. If we change the
temperature in Lm35 by either heater or bulb microcontroller
varies the duty cycle of the PWM accordingly so that the
average power will vary resulting variations in the speed.
8.2 Conclusion
The simulation of the system is working properly and the
design is appropriate according to the modern needs and
technology. The speed of fan depends on temperature and
there is no need for regulating the speed manually. Various
graphs have been plotted to show the varying relationships
between different parameters. PWM technique is found to be
appropriate for controlling fan speed according to room
temperature. After comparing duty cycle and speed of DC
Fan according to temperature variation in software and
hardware we have observed approximately same result.
This design can be further extended in terms of area and
power at layout and characteristic level by using Advanced
VLSI applications. Finally we conclude that this method is
one of the best methods for controlling the speed of the DC
fan motor.
REFERENCES
1. PIC 16F87X A data sheet
2. LM 35 temperature sensor data sheet. http:// www.ti.com
3. L293d Motor driver data sheet
4. LCD016L data sheet.
5. Vaibhav Bhatia and Gavish, International Journal of
Computer Applications (0975 – 8887) Volume 81 – No5,
November 2013
6. R.Krishnan, “Electric Motor Drives Modelling, Analysis,
and Control, Prentice Hall International Inc., New Jersey,
2001.
7. F. Luo, X. Zhao, and Y. Xu, "A new hybrid elevator
group control system scheduling strategy based on
particle swarm simulated annealing optimization
algorithm", Intelligent Control and Automation
(WCICA), 5121-5124, 2010.
8. Fundamentals of electric drive by Gopal k dubey”, narosa
publishing house New Delhi,1989
9. A. Z. Ahmad and M. N. Taib, A study On the DC Motor
Speed Control by Using Back-EMF Voltage, Asia
SENSE SENSOR, 359-364, 2003.
10. I. John, PIC Microcontroller Project Book, second ed.,
Mc Graw-Hill, Singapore, 2000.
11. Xiaodong Xia, Coal Mine Machinery, 202- 204, 32 (8),
2011.
12. J. Vig and A. Ballato, “Ultrasonic Instruments and
Devices”, Academic Press Inc. pp. 637 -701 (Chapter7:
Frequency Control Devices). 1999