this slide is a project of my B.Sc Engineering (mechanical) 4th year.

1. Design, Construction and Testing of A
Temperature Sensing Automatic Speed
Controller for Fan

2. Outlines:
• Introduction
• Objectives
• Design Assumptions
• Name of components
• Block diagram
• Circuit diagram
• Description of components
• Construction of the speed controller
• Working procedure
• PWM(Pulse Width Modulation)
• Test Procedure
• Result and Discussion
• Conclusion and Recommendation

3. Introduction:
What is the project?
The project is controlling the speed of a fan automatically with
variation of temperature detected by a temperature sensor
using microcontroller.
Control system:
There are two types of control system
1. Manual control system
2. Automatic control system
Here an automatic control system is used for this project
Automatic control system:
A control system in which regulating and switching operations
are performed automatically in response to predetermined
conditions.

4. How the system works?
At first the variation of surrounding temperature is detected by a
temperature sensor, then using microcontroller unit the speed of
the fan is controlled. That means when the temperature rises, the
speed of the fan will increase and vice versa.
Why use an automatic speed controller?
Sometimes human beings waste power for nothing while using
electric fan. It is always demanded for us to waste less energy.
Most human beings feel the inconvenience about changing the
fan speed level manually. So this speed control system
automatically changes the speed level of fan according to
temperature changes.

5. Objective:
Objectives of this thesis are to-
I. design an automatic speed controller for fan based
on temperature.
II. construct an automatic speed controller for fan
based on temperature.
III. test an automatic speed controller for fan based on
temperature.

6. Design Assumptions
• The design is based on appropriate sensing capability of
temperature sensor and corresponding response of speed
controller unit.
• Depending on the application, working temperature range
varies. For this system temperature range was assumed 30℃ to
34℃.
• Control system is assumed to have provision for working
under different temperature increment or decrement such as
1℃, 2℃, 3℃…etc. For this system temperature increment or
decrement is assumed 1℃.
• Speed range was assumed from 2550 rpm to 4910 rpm. For
each increment or decrement speed was varied through 550 to
600 rpm.

7. Name of Components:
 Arduino Board (UNO)
 Temperature Sensor (DHT11)
 LCD Display
 DC Motor
 Electronic Speed Controller
 Battery (Power Supply)
 Fan

8. Block Diagram of the Speed Controller
LCD Display
DHT 11
(Temperature
sensor)
LiPo
Battery
BLDC
(Brussless DC
Motor)
Arduino
Board
ESC
(Electronic speed
controller)

9. Circuit Diagram

10. Description of Components:
Arduino Board:
Arduino is a single-board microcontroller, intended to make the
application of interactive objects and environments more easier.
Basically this is very user friendly. There is a microcontroller unit
embedded on it.The code is directly loaded from the computer.
Temperature Sensor:
Basically it is an electronic device that can sense the temperature
which sends signal to the microcontroller unit. Here DHT11 is
used. Its range is between 0 to50⁰c.

11. LCD Display:
LCD display is a flat panel electronic visual
display. 26×4 display board is used in this
project. Value of temperature in degree
celsius and corresponding value
of speed in rpm are displayed.
Electronic Speed Control:
An electronic speed control or ESC is simply
an electronic circuit which is used to control
the speed of dc motor. It can take upto 30Amp
Continuous current. It has the feature of automatic
power cut off, over heat protection, over voltage protection.

12. Battery:
Lithium-ion polymer battery is used
here. It is rechargeable and it provides
required power to arduino board and
dc motor and other components. It can
last for long time after charged once.
DC Motor:
Brushless DC electric motor is a device
powered by a DC electric source via an
integrated power supply which produces an
AC electric signal to drive the motor. It can
give upto 10,300 rpm.

13. Construction of the speed controller

14. Construction of the speed controller(cont’d)

15. Working Procedure:
Arduino Board is the main control unit of our construction. A
microcontroller is embedded on the Arduino board. It is
controlled by numerical coding loaded from computer. It is
the brain of our construction. A LCD display is connected
with the Arduino board which displays temperature reading
and variation of speed of DC motor with respect to
temperature . We have used DHT 11 as temperature sensor. It
can sense temperature from 0 to 50℃. An electronic speed
controller (ESC) is connected with the arduino board. It is
used to control the speed of brushless DC motor(BLDC). A
LiPo battery is used to provide sufficient energy. The BLDC
motor can give up to 10,300 rpm.

16. PWM(Pulse Width Modulation)
Pulse-width modulation (PWM) is a modulation technique that
conforms the width of the pulse, formally the pulse duration,
based on modulator signal information. Here pwm is used for
varying speed of the fan or dc motor corresponding to
temperature reading from temperature sensor(DHT11).

17. Test Procedure
• The speed controller and motor were connected to battery.
Then speed controller was switched on.
• At initial state LCD display was showing surrounding
temperature at that moment and corresponding initial speed of
the fan.
• Then the temperature was increased artificially from 30℃ to
34℃ with the temperature increment by 1℃.
• Variation of speed corresponding to temperature was observed
from the LCD display.

18. Data taken from the speed controller in running condition
Observation
No
Temperature
Reading(℃)
Experimental
Fan
Speed(rpm)
Theoretical
Fan
Speed(rpm)
Error
Percentag
e(%)
01 30℃ 2423 2550 3.08
02 31℃ 3015 3150 4.29
03 32℃ 3580 3710 3.5
04 33℃ 4120 4310 4.41
05 34℃ 4750 4910 3.26
Result and Discussion

19. The speed controller controlled the speed of the fan according to
preassigned condition. Speed of the fan increased as the
surrounding temperature increased and it decreased as the
temperature decreased. Increment of both temperature and
speed can be changed according to user preferences by the
modification in programming.
So the speed controller performed as per the design.

20. Conclusion and Recommendation
A temperature sensing automatic speed controller for fan has
been designed and constructed according to the design. The speed
controller has been tested in various temperature condition and
successful results have been found with minimum error. Errors
have been found by comparing experimental rpm and theoretical
rpm of fan which is around 3.7%.
Recommendation:
 Wi-fi facility can be integrated with the system.
 A keypad can be added for manual input.
 Humidity sensor can be added to the system.

21. THANK YOU