Automatic Fan Regulator

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Problem Identification

Despite the growing popularity of the usage of air conditioners, electric ceiling fans

are still widely in use all over country. Air conditioners, though providing users with the

option of precision temperature regulation along with several other features, remain largely

unaffordable to the majority of consumers. Ceiling fans, on the other hand, with their

relatively lower price ranges, easy installation ability and simple control mechanism still

remain the most popular domestic cooling appliances for user thermal comfort in tropical

countries like Sri Lanka. Presently, conventional choke-styled fan regulators as well as the

more expensive smooth dial regulators are available in the market. These give the user the

option of setting fan speed as desired depending on ambient environmental status

(temperature, humidity etc.) with the latter product affording greater speed variation as

opposed to its’ counterpart.

Perhaps the major problem with fan regulators currently in the Sri Lankan market is

their inability to automatically regulate fan speed corresponding to changes in the external

environment. This proves to be somewhat of an inconvenience to the user. One might often

set the dial of the regulator to its’ maximum speed prior to going to bed with the room being

warm and humid, and yet awake feeling too cold in the morning due to a significant drop in

temperature. The opposite too, that of temperature rising at night, although not frequent, is a

possibility. Furthermore, existing regulators have the additional disadvantage of not being

energy efficient as they even continue to draw the same amount of power when the fan is

operating at a slower speed. Preliminary survey for existing products indicated that similar

products exist in foreign market for considerable higher prices while such products have not

been introduced to Sri Lanka consumer market so far.

To address the issues identified, we decided to introduce a new design with automatic

speed regulation in accordance with ambient temperature and low power consumption for an

affordable price.

Before moving on, we conducted a user survey to get confirmed whether there really

is such a necessity for automatic temperature regulation for long and whether for new product

has its marketability.



User Survey

Group members interviewed 50 people from various parts of the country spanning

across various socio-economic divisions in order to accurately assess what an average Sri

Lankan consumer would require as improvements to existing fans/fan regulators available in

the market.

Each interviewee too was asked to fill in a form detailing the various pieces of

information required. The divisions were as follows:

Age division (young/old)

Income status division (affluent/low income generating)

Geographic locality (urban/rural)

Educational Status (educated/uneducated)

According to gender (male/female)

Results (Summarized) * † * Appendix A for details † Appendix B for Survey form



Based on the data collected above, predominant needs appearing multiple times

across all listed categories were identified.

Out of major needs identified above, two significant needs have been accounting for

more than 50% of all needs. Those are,

Facility of remote control.

Automatic Remote Speed Control in according with ambient temperature.

Although Automatic speed control would satisfy the necessity of having remote

control and adding remote control increases the total cost, we decided to consider the facility

of remote control in conceptual design while having a thought of dropping that feature if itadds unnecessary complexity to the design. Then we developed the following design

specifications taking above mentioned user needs and technical issues in to consideration.

5%

23%

31%4%

3%

3%

3%

3%

25%

Major Needs Identified

Power Saving Mechanism

Automatic Control depending onRoom being too Warm/Cold

Remote Control

Display Options

Operation during Power Failure

Dust Removal Mechanism

Automatic On/Off Switching

Uniform/Directed Blowing



Design Specifications

Interface to switch the fan on and off.

Interface to switch between auto and manual mode.*

Interface to set reference temperature (In auto mode) Interface to set fan speed (In manual mode)*

Continues variation of speed in accord ance with ambient temperature. †

* Even though the user survey doesn’t indicate any necessary for both auto and manual modes together there isan issue arises when manual control is necessary for some special cases. So we decided to add both auto andmanual mode to work in harmony.

† Even though user need survey does not indicate continues variation of speed in accordance with temperature,we added it as a hidden need as it makes consumer more comfortable and does not require extra cost.

To fulfil the above we came up with 2 different conceptual designs.

Conceptual Designs

Design 1

In auto mode of operation, the reference temperature value set by the user and

ambient temperature value read through the temperature sensor are fed into control unit. The

control unit calculates the error between two values and generates a signal accordingly and

passes it to voltage regulator. Voltage regulator regulates the power input to the fan in

accordance with the signal received from control unit.

In manual mode of operation, only the speed value set by the user is fed into control

unit and then the control unit generates a signal with respect to the error value between

received value and pre-defined reference value. This calculated value is fed into the voltage

regulator which regulates the power input to the fan in accordance with received signal.

Design 2

Temperature sensor and the user interface are located in a remote control. It sends the

values read through sensor and user interface to a receiver which is placed inside a gadget

which is attached to fan itself. All other functions are similar to the conceptual design 1

except the facility of remote control.



Design 1- Block Diagram



Design 2- Block Diagram



User Input

Variable Resistor

Power Circuit

Rectif y_and_Regulate_Voltage

VDD_12V

GND

VDD_5V

AC_In1AC_In2

AC_Power

230V50Hz

T1

TRANSFORMER

1 5

4 8

Temperature Sensor LM351

2

3VI

GND VO

Zero Crossing Detector

Zero_Crossing_Detection

VDD_12V

AC_In2

GND

AC_In1Output to thePIC

01

Intelligent Fan Regulator

A

1 7Thursday, September 22, 2011

Title

Size Document Number Rev

Date: Sheet of

Control Unit

PIC

Temperature Sensor INPUT

Variable Resistor IN PUT

Power

Zero Crossing INPUT

OUTPUT to TRIAC Circuit

FAN

2

1

TRIAC Circuit

TRIAC_CIRCUIT

INPUT1

INPUT2

OUTPUT1OUTPUT2

Even though the 2 nd conceptual design provides the consumer with more comfort and

ease of use, its higher cost draws back the demand for it. So we decided to start with the 1 st

conceptual design as it is more economical and fulfills the user needs to a satisfactory level.

Preliminary design

As we chose 1 st conceptual design to work on, we come up with a preliminary design

which describes the implementation process of 1 st conceptual design. We employed top down

hierarchical design technique as we are novel to the subject and also the design is a new one.

Top most level of the design

Take the user input from variable resister and varies the fan speed in accordance with

ambient temperature sensed from the temperature sensor (LM35).



VDD_5V

Voltage_Regulator_Circuit

Regulate_Voltages

DC_12V

GND

VDD_12V

VDD_5V

GND

Rectri

Rectify

AC_In1 DC_12V

AC_In2 GND

AC_In2 GND

VDD_12VAC_In1

Control Unit

PIC


Variable Resistor I NPUT

PowerZero Crossing INPUT


PIC 16F877A

PIC16F877A

20

32

19

27

2625

1

24232221

1112131415161718

23456789

4039383736353433

302928

OSC2/CLKOUT

MCLR/VPP

OSC1/CLK

TEST

RA0/INTRA1/T0CLK

VDD

RA2RA3

RA4/RX/DTRA5/TX/CK

RB0/CAP1RB1/CAP2

RB2/PWM1RB3/PWM2

RB4/TCLK12RB5/TCLK3

RB6RB7

RC0/AD0RC1/AD1RC2/AD2RC3/AD3RC4/AD4RC5/AD5RC6/AD6RC7/AD7

RD0/AD8RD1/AD9RD2/AD10RD3/AD11RD4/AD12RD5/AD13RD6/AD14RD7/AD15

RE0/ALERE1/OERE2/WR


Variable Resistor INPUT

Zero Crossing INPUT

Power


Major blocks used for top level

Power Circuit

Control Unit


TRIAC Circuit

Second Level of the Design

Power circuit

Employs a rectifier circuit and a voltage regulator circuit to convert normal AC to12V and 5V DC to feed control circuit and other peripheral circuits with.

Control Circuit

Employs a PIC16F877A microcontroller to calculate error between user input and

temperature sensor input and to generate a pulse accordingly.




Zero_Crossing_Detection

VDD_12V

AC_In2

GND

AC_In1Output to the PIC

AC_In1

C1

1n

R2 1

VDD_12V

R

2

1

AC_In2

Output to the PIC

R2 1

U1A

LM6152BCN

2

3

4

1

8

-

+ V -

OUT

V +

GND

TRIAC Circuit

TRIAC_CIRCUIT

INPUT1

INPUT2

OUTPUT1OUTPUT2 R1

1k

U1MOC3011

1

2

6

4

R3

1k

U2BT136

1

2

3VI

G N D

VO

INPUT1

OUTPUT1

INPUT2

R2

1k

OUTPUT2


Employs a LM 339 zero crossing detector to detect zero crossing of AC and to informmicrocontroller through an interrupt.

TRIAC and Octocoupler Circuit

Employs an octocoupler (µOC 3011) to isolate AC and DC circuit portions and

TRIAC (BT 136) to regulate the fan speed by controlling power supplied to fan.



Rectri

Rectify

AC_In1 DC_12V

AC_In2GND

AC_In2

0

GND

D4

D1N4007

D2

D1N4007

C1

500u

D3

D1N4007

DC_12V

D1

D1N4007

AC_In1

D5

D1N4494

Voltage_Regulator_Circuit

Regulate_Voltages

DC_12V

GND

VDD_12V

VDD_5V

GND

GND

VDD_5VC3

0.33u

U1MC7805C

1 2

3

IN OUT G N D

VDD_12V

GND

U2MC7812C

1 2

3

IN OUT G N D

C2

0.1u

0

C4

0.1u

C1

0.33u

DC_12V

Third level of design (for power circuit)

Rectifier Circuit

Employs IN40075 in a full wave rectifier bridge.

Voltage Regulator Circuit

Employs 7812 and 7805 voltage regulators to regulate DC at 12V and 5V respective.

Enclosure Design

After obtaining an accurate preliminary design, we next moved on to designing of

proper enclosure for our product. We were able to come up with a suitable enclosure which

suits the design as follows.



PCB Design

PCB design which suits to the enclosure.



Part List

Part Reference

0.33u C10.1u C20.33u C30.1u C4500u C101n C12D1N4007 D1D1N4007 D2D1N4007 D3D1N4007 D4D1N4494 D5Ceiling FANCON4 J1PIC_16F877A PIC_16F877A1k R11k R21k R3Ceiling R50Ceiling R51Ceiling R52

TRANSFORMER T1MOC3011 U1MC7812C U2LM6152BCN U4MC7805C U10BT136 U11



00.5

11.5

22.5

33.5

4

4.5

PS TS AC HS B MR RPM PL SD RC

F r e q u e n c y

Need (Key)

Agewise Need Distribution

Below 30

Above 30

Appendix A

Data has been presented according to the five divisions mentioned above along with

suitable histograms to enhanced clarity of the information.

Age Division

Table 1: Problems and Needs Identified by Users According to Age Category

Problems IdentifiedAge Category

Needs IdentifiedAge Category

< 30 > 30 < 30 > 30

High electricitybill/consumption 2 2 Power saving mechanism (PS) 1 1

Problem of having to go to the

regulator in order to vary speed3 Temperature sensitivity (TS) 3

Noisy operation 1 Automated control (AC) 1

Absence of mosquitoerepellent 1 Humidity sensitivity (HS) 1

Absence of automatic ambienttemperature sensitivity 1 Bulb fixed to ceiling fan (B) 1

Malfunctioning timers 1 Mosquitoe repellent (chemicalagent) (MR) 1

Dryness of skin 1 Display RPM (RPM) 1

Dust accumulation anddifficulty involved in cleaning 4 Fan to work even during power

failure (PF) 1

Breathing difficulties due tohigh speeds 1

Mechanism to prevent drynessof skin during operation (SD) 1

Remote control capability(RC) 4

Figure 1: Histogram of Needs Identified by Users According to Age Category



Income Status

Table 2: Problems and Needs Identified by Users According to Income Status Category

Problems IdentifiedMonthlyIncome

Needs Identified

MonthlyIncome

< 15,000LKR

> 15,000LKR

< 15,000LKR

> 15,000LKR

Noisy operation 1 1 Continuous speed regulation(CS) 1

Requirement for frequentrepairing 1 Remote Control (RC) 1 1

High electricity consumption 1 1 Embedded devices instead of mechanical control (ED)

1

Dust accumulation 2Flexibility with alternativepower sources (FAP) 1Ability to orient direction of blowing (OD) 1

Timer option (TO) 1

Automatic speed control (AC) 1

Figure 2: Histogram of Needs Identified by Users According to Income Status Category

00.5

11.5

22.5

33.5

44.5

CS RC ED FAP OD TO AC

F r e q u e n c y

Need (Key)

Income Generation Status Based Need Distribution

Low Income

Affluent



Geographic Locality

Table 3: Problems and Needs Identified by Users According to Geographic Locality

Problems IdentifiedLocality

Needs IdentifiedLocality

Urban Rural Urban Rural

Noisy operation 1 2 Automatic fan speed controlaccording to room temperature 3 2

Drop of temperature during thenight (getting too cold) 1 2 Remote control (RC) 1

High electricity consumption 1 Power saving mechanism (PS) 1

Dust accumulation 1

Figure 3: Histogram of Needs Identified by Users According to Geographic Locality

00.5

11.5

22.5

33.5

44.5

AC RC PS

F r e q u e n c y

Need (Key)

Geogrophical Location Base Need Identification

Urban

Rural



Educational Status

Table 4: Problems and Needs Identified by Users According to Educational Status Category

Problems IdentifiedStatus

Needs IdentifiedStatus

UptoO/L

AboveO/L

UptoO/L

AboveO/L

Health issues 2 1Automatic switching on/off depending on human presence(AS)

2

Dryness of skin 1 Remote Control (RC) 3 1

Non-uniform blowing 1 Display Options (DO) 1

Dust accumulation 2 Dust removal mechanism (DR) 2

Motor getting weak 1 Automatic speed control (AC) 2

Absence of timer features 1

Figure 4: Histogram of Needs Identified by Users According to Educational Status Category

00.5

11.5

22.5

33.5

44.5

RC ASO DO DR AC

F r e q u e n c y

Need (Key)

Educational Status Based Need Distribution

Upto GCE O/L

Above GCE O/L



Gender Based

Table 5: Problems and Needs Identified by Users According to Gender

Problems IdentifiedGender

Needs IdentifiedGender

Male Female Male Female

Health issues 4 Temperature regulation (TC) 1

Non-uniform blowing 1 2 Remote Control (RC) 5 3

High electricity consumption 2 Mechanism to reduce noisiness(RN) 1

Shadows appearing in theroom 1 Automatic speed control (AC) 1

Inability to operate duringpower failure 1 Battery to enable operation

during power failure (BPL) 1

Noisy operation 1 2 Automatic temperature-sensitive speed regulation (TS) 1 1

Inability to regulatetemperature

1 Protective mesh (PM) 1

Problem of having to go to theregulator in order to varyspeed

1Mechanism to ensure uniformblowing to all parts of a room(UB)

1

Figure 5: Histogram of Needs Identified by Users According to Gender

0

1

2

3

4

5

6

TC RC RN AC BPL TS PM UB

F r e q u e n c y

Need (Key)

Gender-wise Need Distribution

Male

Female



Appendix B

User Survey Form

Age : .....................................Residence (urban/rural) : ........................................District : .....................................Profession : .....................................Gender : .....................................

1. Do you have an air conditioner at home (yes/no)?

2. Do you have a fan at home? (yes/no) if yesCeiling fan : .........................Table fan : .........................

3. At what time of the day do you mostly use your air conditioner/fan? (Morning / Afternoon / At Night)

4. What are the problems you face when using your fan?..............................................................................................................................................................................................................................................................................................................................................................................................................................

5. What improvement would you like to have included in your fan?..............................................................................................................................................................................................................................................................................................................................................................................................................................

6. If you had an air conditioner instead of a fan, you would (like it / would not like it / makeno difference)Reason : ..................................................................................................................................

7. How many units of electricity do you consume per montha. Less than 60b. Between 60 and 90c. Between 90 and 150d. Between 150 and 300e. Do not know

8. Are you concerned about the power consumption of the electric goods you purchase?

..........................................................................................................................................

Automatic Fan Regulator

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