Home Automation System based on PLC

Comfort room with temperature control based on microcontroller

MEKELLE UNIVERSITY ELECTRICAL AND COMPUTER ENGINERING Page 1

CHAPTER ONE

INTRODUCTION

This project is consisting of all information regarding the comfort room with temperature

control based on microcontroller. In this chapter; we are providing an overview of the project

including the project background, project statement and objectives of project.

1.1. Project Background

Room is all about comfort. From now on, our room can be made even more comfortable

with automation on temperature controller to move the speed of fan depend on the

temperature day and night. Also become more secure with the alarm system that working on

the changes of temperature when the temperature reaches the level of bad situation (fire).

Everything will become easier every day. More new technologies were created every single

day. So this project is mainly purpose to make life become easier and live with technologies

system every day and we will be more alert and secure with any accidentally cases that

happened such as the room or house is on fire.

This project also provides the designation of an ambient temperature measurement circuit.

The motivation for doing this project is the fact that temperature measurement has become an

integral part of any control system operating in a temperature sensitive environment and the

various learning outcomes associated during the implementation of the project.

As we all know temperature is a physical property of matter that quantitatively expresses the

common notions of hot and cold. Objects of low temperature are cold, while various degrees

of higher temperatures are referred to as warm or hot.In this project the ambient temperature

will be displayed on a LCD. The 16F877A PIC Microcontroller will be used for handling all

the required computations and control



1.2 Problem statement

As engineering students we aimed to provide an excellent part of knowledge that shows the

use of technology in our lives. In order to help our government to produce the skillful and

excellent of workers, later. Also this project can give the information and knowledge about

the current temperature in our lives and the most important is self-awareness that reminds us

of to save our green world.

So, we providing new kind of technology which is using microcontroller based on

temperature controller to control the fan speed automatically depend on the temperature in

the room and give the emergencies signal if any bad cases like overheat happened. The goal

of this comfort room is to save our energy, times and much more important is to help old

people and disable person.

Current technology doesn’t use the automatic switch. Nowadays, many rooms or houses

use a manual switch to on or off the fan. So our lives will become easier and comfortable if

all the things happened automatically.



1.3. Objective of the project

The objective this project is:

1, To create the comfort room for better lives to make our life simple and acknowledge .

2, To be familiar with PIC and c program and to be accurate.

3, Reduce our energy and time usages because microcontroller makes automation for this

project application.

1.4. Scope of the project

1. Create for an old man to make their lives simple and easy. Also we aimed this

project to disable person that hard to manually switch on the function of

electronic and electric part at the room or house.

2. Reduce our energy and time usages because microcontroller makes automation

for this project application.

3. Lastly, this project provided the security signal when the emergency cases

happened like the room or house is on fire.

This project can be placed to many part of area (room or house). For example:

1) Hospital

2) Office

3) House

4) Lab



CHAPTER TWO

LITERATURE REVIEW

2.1. A Brief History of Temperature

Temperature is by far the most measured parameter. It impacts the physical, chemical and

biological world in numerous ways. Yet, a full appreciation of the complexities of

temperature and its measurement has been relatively slow to develop.

Intuitively, people have known about temperature for a long time: fire is hot and snow is

cold. Greater knowledge was gained as man attempted to work with metals through the

bronze and iron ages. Some of the technological processes required a degree of control over

temperature, but to control temperature you need to be able to measure what you are

controlling.

We were using the manual speed controlling of fan. Unlike air conditioners, fans only move

air. They do not directly change its speed refer to current state of temperature. We know the

used of potentiometer here as the main component to put the speed by level but we need to

change the speed manually by push the switch button.

2.2 Brief history of temperature measurement

Ancient people were physically aware of hot and cold and probably related temperature by

thesize of the fire needed, and how close to sit, to keep warm.

An Australian tribe, still primitive, uses dog instead of blankets to keep warm, thus, they can

relate temperature by the dog. A moderately cool night may require two dogs to keep warm,

thus it is a two-dog night. An icy night would be a six-dog night.



Early people were, at first, fire tenders, maintaining fires originally started by natural causes.

Later, they learned how to make fire and became fire makers.

Eventually, they became fire managers as they learned to work with fire to gain the heat

needed to boil water, cook meat, fire pottery (500°F or 257°C ), work with copper, tin, bronze

(an alloy of copper and tin) and iron, and to make glass. Although they had no quantitative

measuring devices to determine how hot a fire was, they developed recipes for building

different types of fires and probably used a physical indicator, such as some mineral or metal

melting, to indicate the correct temperature for a particular process.

The ancient Greeks knew that air expanded when heated and applied the principle

mechanically, but they developed no means of measuring temperature or amount of heat

needed and devised no measuring instruments.Snow and again, when heated with a candle.

The space on the column, between these two points was then divided into 110 equal parts.

The Italian scientist Galileo (1564-1642) is one of the first recorded to attempt to measure

temperature in 1592. His measuring device consisted of a bulb of air, which, when heated,

forced liquid (water or spirits of wine [alcohol]) down a column immersed in an open

container of the liquid (see Figure 2.1). In about 1611, the thermometer was calibrated by

Sanctorius Sanctorius, a colleague of Galileo, who noted the liquid level when the bulb was

cooled with melting.

Figure 2.1. Galileo’s air Thermometer



Jean Rey (1582-1645), a French physician, invented the first liquid thermometer in 1632.

His thermometer consisted of a flask with a long slender neck partially filled with water (see

Figure 2). As the temperature changed, the liquid level would rise or fall in response.

Unfortunately, it was later realized that these early thermometers were affected by changes in

atmospheric pressure. Sealed, liquid in glass thermometers were first made in about 1644. Of

the various liquids used, such as water, alcohol, and mercury, alcohol was preferred since is

showed the greatest expansion in response to increases in temperature

Figure 2.2. Rey’s liquid thermometer

By the early 18th century, as many as 35 different temperature scales had been devised. In

1714, Daniel Gabriel Fahrenheit invented both the mercury and the alcohol thermometer.

Fahrenheit's mercury thermometer consists of a capillary tube which after being filled with

mercury is heated to expand the mercury and expel the air from the tube. The tube is then

sealed, leaving the mercury free to expand and contract with temperature changes. Although

the mercury thermometer is not as sensitive as the air thermometer, by being sealed it is not

affected by the atmospheric pressure. Mercury freezes at -39° Celsius, so it cannot be used to

measure temperature below this point.

Alcohol, on the other hand, freezes at -113° Celsius, allowing much lower temperatures to be

measured.



Later in the 18th century, Anders Celsius realized that it would be advantageous to use more

common calibration references and to divide the scale into 100 increments instead of 96. He

chose to use one hundred degrees as the freezing point and zero degrees as the boiling point

of water. Sensibly the scale was later reversed and the Centigrade scale was born. See Olof

Beckman's short History of the Celsius Temperature Scale.

The late 19th century saw the introduction of bimetallic temperature sensor. These

thermometers contain no liquid but operate on the principle of unequal expansion between

two metals. Since different metals expand at different rates, one metal that is bonded to

another, will bend in one direction when heated and will bend in the opposite direction when

cooled (hence the term Bimetallic Thermometer or BiMets). This bending motion is

transmitted, by a suitable mechanical linkage, to a pointer that moves across a calibrated

scale. Although not as accurate as liquid in glass thermometers, BiMets are more hardly, easy

to read and have a wider span, making them ideal for many industrial applications.

The 20th century also saw the refinement of the temperature scale. Temperatures can now be

measured to within about 0.001°C over a wide range, although it is not a simple task. The

most recent change occurred with the updating of the International Temperature Scale in

1990 to the International Temperature Scale of 1990 (ITS-90). This document also covers the

recent history of temperature standards.

LM 35 sensor can work as thermometer. It is the precision temperature sensor with output

linearly proportional to the Celsius (Centigrade) temperature. It also operates in single supply

and draws only 60 microampere current. Its self-heating is as low as 0.1 degree at still air.

LM 35 is rated to operate between -55 to +150 Degree Celsius. LM 35C operates between -

40 to +110 Degree Celsius. Supply voltage required for LM 35 ranges between 4 to 30 Volts

DC.

Nowadays, we are using the manual speed controlling of fan. Unlike air conditioners, fans

only move air. They do not directly change its speed refer to current state of temperature. We

know the used of potentiometer here as the main component to put the speed by level but we

need to change the speed manually by push the switch button.



What is potentiometer? A potentiometer is a three-terminal resistor with a sliding contact that

forms an adjustable voltage divider. If only two terminals are used (one side and the wiper), it

acts as a variable resistor or rheostat. Potentiometers are commonly used to control electrical

devices.

Other than that, we know that our computers using the fan as the cooling system to protect

the Central Processing Unit from getting overheat. Fan will control automatically and adjusts

the fan speed depending on the temperature of the CPU. If it isn't properly cooled, the CPU

will overheat and become permanently damaged. Standard fan control settings simply set the

fan to run at a constant speed all the times that the computer is on. This normally involves

setting a minimum and maximum fan speed, as well as a high and low CPU temperature. At

the low temperature, the fan will start running at the minimum fan speed. The fan speed will

vary in line with the CPU temperature until it reaches the high CPU temperature.



CHAPTER THREE

CONFORT ROOM WITH TEMPRETURE CONTROL BASED ON

MICROCONROLLER

This part is about the methodology which means to elaborate of how the project can be

implemented on a few requirements. There are flow charts and project block diagram with

complete explanations, hardware and software development and project planning. To

complete this task we need to make the research of every method used and understand those

things to prevent the mistake and make the project run smoothly. There are important parts of

hardware and software used to move the project to be functioned.We are using

Microcontroller as the main brain of the project. This Microcontroller has many functions to

work the application automatically, just put the simple program then all can run smoothly.

All of these important components were explained in this chapter.

Figure 3.1: Block Diagram of room temperature control based on pic



Figure 3.2: Process of room temperature control based on PIC

The block diagram from the figure 3.1 and 3.2 show the complete part of hardware used to

project. The circuit starts working when the AC supply is turned on. Then the supply change

from AC to DC by using the adapter. DC supply 12 volt was connected to the IC regulator

circuit to produce 5 volt stable voltage. Then the sensor LM 35 start to function as the

component to measure the changes of temperature surrounds the area. All the application

were controlled by the PIC 16F877A to produce the output. We can put the PIC as a brain of

the circuit. It is because that all functions in this block diagram are depending on this

component. LCD, fan and buzzer are the output that should be set with the program of PIC.

LCD used to measure and show the changes of temperature value. The fans start to function

when the switch is turned on and the speed is up depending on current temperature. High

value of temperature will caused high speed of fan. Then the buzzer only shows the

emergency situation if the temperature reached unusual situation temperature.



Figure 3.3: Flow chart of room temperature control based on PIC

The flow chart starts to function when the switch is turn on. The supply voltage flow to the

circuit and make all the circuit including PIC to work on all application there. Level 1

(normal mode) of fan starts to function after that. If the temperature reached more than

30ºcelcius the fan automatically change the speed to level 2. The speed of fan’s become more

faster.

The speed will change back to normal mode if the temperatures reduce. So, we add the

application to show more secure and show an emergency case to give the signal if any bad

cases happened.



The buzzer will function if the temperature more than 40ºC (to make an easier for our

demonstration, we put the emergency temperature only 40 ºC). All of applications here are

working automatically with the use of microcontroller.

3.1 Hardware Development

Figure 3.4: PIC16F877A Microcontroller

The 16F877A is one of the most popular PIC microcontrollers. It comes in a 40 pin DIP pin

out and it has many internal peripherals. The 40 pins make it easier to use the peripherals as

the functions are spread out over the pins. This makes it easier to decide what external

devices to attach without worrying too much if there enough pins to do the job.

One of the main advantages is that each pin is only shared between two or three functions so

it’s easier to decide what the pin function (other devices have up to 5 functions for a pin).



A disadvantage of the device is that it has no internal oscillator so you will need an external

crystal of other clock source.

The microcontroller PIC16F877A is connected to the peripheral and internal components. As

shown in the figure 3.5.

Figure 3.5 connection of PIC16F877A with peripherals and internal

PIC

microcontroller

Feature

PIC microcontroller

feature description

Flash memory Re-programmable program storage.

RAM Memory storage for variables.

EEPROM Long term stable memory: Electrically

http://www.best-microcontroller-projects.com/pic-microcontroller.html#Flash_memory

http://www.best-microcontroller-projects.com/pic-microcontroller.html#RAM_and_EEPROM_size

http://www.best-microcontroller-projects.com/pic-microcontroller.html#RAM_and_EEPROM_size



Erasable Programmable Read

Only Memory.

I/O ports High current Input Output ports (with pin

direction change).

Timers/Counters Typically 3.

USART Built in RS232 protocol (only needs level

translator chip).

CCP Capture/Compare/PWM module.

SSP I2C and SPI Interfaces.

Comparator An analogue comparator and internal

voltage reference.

ADC Analogue to digital converter.

PSP Parallel Slave Port (for 8 bit

microprocessor systems).

LCD LCD interface.

Special features ICSP,WDT,BOR,POR,PWRT,OST,SLEEP

ICSP Simple programming using In Circuit

Serial Programming.

Table 3.1 Feature of PIC16F877A microcontroller

Programing is one of the most useful features of a PIC microcontroller is that you can re-

program them as they use flash memory (if you choose a part with an F in the part number

e.g. 12F675 not 12C509).

Input/output PIC Microcontroller can control outputs and react to inputs.

Figure 3.6: LM 35 Sensors of the room temperature control

http://www.best-microcontroller-projects.com/pic-microcontroller.html#IO_Ports

http://www.best-microcontroller-projects.com/pic-microcontroller.html#Timer__Counters

http://www.best-microcontroller-projects.com/pic-microcontroller.html#USART

http://www.best-microcontroller-projects.com/pic-microcontroller.html#CCP_

http://www.best-microcontroller-projects.com/pic-microcontroller.html#SSP_

http://www.best-microcontroller-projects.com/pic-microcontroller.html#Comparator_and_comparator_voltage

http://www.best-microcontroller-projects.com/pic-microcontroller.html#ADC_

http://www.best-microcontroller-projects.com/pic-microcontroller.html#PSP

http://www.best-microcontroller-projects.com/pic-microcontroller.html#LCD

http://www.best-microcontroller-projects.com/pic-microcontroller.html#Special_Features

http://www.best-microcontroller-projects.com/pic-microcontroller.html#ICSP

http://www.best-microcontroller-projects.com/pic-microcontroller.html#ICSP



It is the precision temperature sensor with output linearly proportional to the Celsius

(Centigrade) temperature. It operates in single supply and draws only 60 uA current. Its self-

heating is as low as 0.1 degree at still air. LM 35 is rated to operate between -55 to +150

Degree Celsius. LM 35C operates between -40 to +110 Degree Celsius. Supply voltage

required for LM 35 ranges between 4 to 30 Voltages.

Figure 3.7: LCD temperature Display

LCD is an electronically-modulated optical device shaped into a thin, flat panel made up of

any number of color or monochrome pixels filled with liquid crystals and arrayed in front of a

light source (backlight) or reflector.This LCD is good to demonstrate and do measurement

from the temperature sensor. It can show the changes of value from the sensor clearly. Also

this LCD is cheaper than the others. Here the specification of LM 016L

LCD MODULE, A/N 16X2

No. of Digits / Alpha:32

Character Count x Line:16 x 2

Supply Voltage:5V

Display Area Width:61mm

Display Area Height:15.8mm

Operating Temperature Range:0°C to +50°C

External Depth:15mm

External Length / Height:44mm

External Width:84mm

Operating Temperature Max:50°C

Operating Temperature Min:0°C



Figure 3.8: LM 7805 of voltage regulator IC

LM7805 is a voltage regulator integrated circuit. It is a member of 78xx series of fixed

linear voltage regulator ICs. The voltage source in a circuit may have fluctuations and would

not give the fixed voltage output.The voltage regulator IC maintains the output voltage at a

constant value. The xx in 78xx indicates the fixed output voltage it is designed to provide.

7805 provides +5V regulated power supply. Capacitors of suitable values can be connected at

input and output pins depending upon the respective voltage levels.

3.3 Software development

3.3.1 CCS C compiler

We are using C compiler to create the program and run the compilation to get zero error.

Produce a range of compilers that cover all 8 bit PICs (PIC10, PIC12, PIC14, PIC16, and

PIC18) and a few of the higher spec chips (PIC24 and dsPIC). Although there were a lot of

languages that can be used for the programming, but internally the computer only understand

two numerical values which are 0 and 1 that were also known as the binary number. The

interesting about the C languages is it is easy to understand the programming compared to

Assembly languages or other languages.

Figure 3.9: CCS C Compiler



3.3.2 Multism

Multism is an electronic schematic capture and simulation program which is part of a

suite of circuit design programs, along with NI Ultiboard. Multisim is one of the few circuit

design programs to employ the original Berkeley SPICE based software simulation. Multisim

was originally created by a company named Electronics Workbench, which is now a division

of National Instruments. Multisim includes microcontroller simulation (formerly known as

MultiMCU), as well as integrated import and export features to the Printed Circuit Board

layout software in the suite, Ultiboard. Multisim is widely used in academia and industry for

circuits education, electronic schematic design and SPICE simulation.

Figure 3.10: Multism

3.3.3 PIC Kit 2 and USB burner- version 2.55

Pickit2 is the high-speed programmer & Debugger designed especially for development

programming of PIC single chip microcomputer. The product is featured with small volume,

low power consumption, high reliability as well as easy and convenient operation. Pickit2 is

applicable for almost all PIC10/12/16/18/24 and dspic30/33 FLASH series Microcontroller's

Programming. Pickit2 is a USB based ICSP (In Circuit Serial Programming) programmer.

Since its first release, Microchip has opened all resource of Pickit2 to the public, which

includes all software source code and hardware schematics.



Figure 3.11: PIC Kit 2 & USB burner



CHAPTER FOUR

RESULT AND ANALYSIS

This chapter contains the result of fan speed and buzzer. All the system controlled by

microcontroller and temperature sensor to make it work automatically. It consists of the

hardware and software development as mentioned in the methodology of chapter 3. Upon the

completion of hardware construction and programming process, the project is needed to be

tested to confirm of its function success. The tests are divided into certain parts. The parts are

voltage regulator supply, microcontroller, sensor temperature, PWM motor circuit and

programming.

4.1. Results

Speed Level of temperature

Slow Level 1

Fast Level 2

Emergency Level 3

Table 4.1: Result

Referring to above table, the slow level mean the speed of fan is on normal state. The fan

will function when the switch is turned on. If the temperature reached above 30⁰C the speed

will change automatically to level 2 and will change to level 3 if more than 40⁰C.



4.1 Analysis Circuit

Figure 4.1: Complete Circuit without PWM Circuit of room temperature control

Figure 4.2: Full View Circuit room temperature control



Figure 4.3: Regulator Circuit (12v and 5v)

The AC supply is already converted by the adapter to give 12V input in this circuit. The

function of this circuit is to produce the 5volts of VCC. Both of the voltages (12volt and

5volt) were used in this project. Both of output voltages were connected to all circuit and give

the supply to function all of it. From here, it is easier to make the connection.

Figure 4.4: Simulation of Regulator Circuit



Figure 4.5: Sketch of PWM Motor Circuit

PWM Motor circuit above used to move the fan with microcontroller programming. The

speed can be adjusted refer to the duty percentages. The MOSFET component was function

as the speed controller to control all the level of duty (speed of fan). The duty programming

was set in the PIC.

Figure 4.6: LM 35 sensor and LCD Interfacing

LCD will display and measure the current of temperature in the room. Above picture show

the designation of the LCD and LM 35 sensor interfaced with PIC.



Figure 4.7: Test Circuit and Measurement

The LM 35 will detect the temperature and every part of rising temperature will state on the

display. The speed of fan will change refer to the specification we state in PIC programming.



CHAPTER FIVE

CONCLUSION

5.1 Project Conclusion

Everybody dream to live with easier life and put some secure awareness among themself.

This project make the wish come true to stay the life more comfortable. There are many

application of Smart Room. But this project only to show the uses of temperature in our lives

and make development of it. So if we understand more about temperature, we know how to

manage the situation and also can reduce the time and energy we use every day like switch on

the fan manually and never alert of the accident happened in the rooms or house.

All the circuit and application of it were done greatly. The temperature can be measure and

read from the display. This project also gives the information about current temperature. So

we will be more knowledgeable and self-awareness. We will have more self-motivated to

work harder to reduce the current problem temperature in our world, and then will save our

green life to live in peaceful and harmony situation.

5.2 Project Limitation

The main important thing of research and development is a cost, especially for

electronics components of relates to this project.

Hard to create many application because some of the component are not sell in

here. Need to order from other country.



5.3 Future Project Recommendation

A series of enhancement, modification and upgrading have been carried out

to produce better performance for the future enhancement. Below is some suggestion from

our research to upgrading this project:

Make the circuit more compact and smaller. Easy to keep and place it to our house.

Produce the system for user where the system can send the SMS directly the status of

security level in house to them.

Controlling the room application using computer. Use Visual Basic software that can

control all operation for example just clicking the mouse then can open the light or

fan.

Add more applications like solar and also make an improvement of the circuit. Make

it more compact and easy to keep it.

Produce a backup system like using a generator or battery as a support supply. So if

blackout happened the system still can run properly.



REFERENCES

BOOKS

1. Renato Nuns, José Delgado, "An Architecture for a Home Automation System",

ICECS '98 – International Conference on Electronics, Circuits and Systems,

September 1998, pp.259 262.

2. Muhammad Ali Maizidi,The 8051 microcontroller & Embeded Systems

3. Thedore F Bogart, Jr. Electric Circuits – PIC GUIDE

INTERNET WEBSITE

1. www.alldatasheet.com/datasheet-pdf/pdf/.../PIC16F87X.html

2. http://ezinearticles.com/?Home-Security-History&id=2129354

3. http://www.facstaff.bucknell.edu/mastascu/eLessonsHTML/Sensors/TempLM35.html



APPENDICES

Appendix A: Programming

To control the PIC, we need the programs to control all the circuit. Here the result of it:

/* this a project c programming for microcontroller based temperature control system */

/* Mekelle university _EIT-M_ Electrical & Computer Engineering*/

#include<16F877A.h>

#fuses HS,NOLVP,NOWDT

#use delay(clock=20000000)

#include<lcd.c>

Void main ()

{

float mytemp;

setup_port_a (RA0_ANALOG);

setup_adc(ADC_CLOCK_INTERNAL);

set_adc_channel(0);

setup_ccp1(CCP_PWM); // Configure CCP1 as a PWM

setup_timer_2(T2_DIV_BY_16, 500, 2); // 500 Hz

//starting mode//

lcd_init();

lcd_putc("\fTemperature");

printf (lcd_putc);

delay_ms(3000);



lcd_init();

while(true)

{

delay_ms(800);

mytemp=(read_adc()*(5.0/254))*100;

lcd_gotoxy(1,1);

printf(lcd_putc, "Temp Now:%f\n ", mytemp);

output_low(pin_B5);

output_high(pin_B7);

if(mytemp<=35.0)

{

set_pwm1_duty(1000);

}

if(mytemp<30.0)

{

set_pwm1_duty(200); // 25% duty cycle on pin C2

}

if(mytemp>=40.0)

{

output_high(pin_B5);

set_pwm1_duty(1000);

}



}

}

APPENDIX B: LM7805 Regulator



PIC16F87X Data Sheet 28/40-Pin 8-Bit CMOS FLASH Microcontrollers

Devices Included in this Data Sheet:

PIC16F877

Microcontroller Core Features:

High performance RISC CPU

Operating speed: DC - 20 MHz clock input DC - 200 ns instruction

cycle

Up to 8K x 14 words of FLASH Program Memory, Up to 368 x 8

bytes of Data Memory (RAM) Up to 256 x 8 bytes of EEPROM Data

Memory



Pinout compatible to the PIC16C73B/74B/76/77

Interrupt capability (up to 14 sources)

Eight level deep hardware stack

Direct, indirect and relative addressing modes

Power-on Reset (POR)

Power-up Timer (PWRT) and Oscillator Start-up Timer (OST)

Watchdog Timer (WDT) with its own on-chip RC oscillator for

reliable operation

Programmable code protection

Single 5V In-Circuit Serial Programming capability

Wide operating voltage range: 2.0V to 5.5V

High Sink/Source Current: 25 Ma

Commercial, Industrial and Extended temperature ranges

Low-power consumption:

- < 0.6 mA typical @ 3V, 4 MHz

- 20 μA typical @ 3V, 32 kHz

- < 1 μA typical standby current

Documents

Home Automation System based on PLC