Bluetooth based home automation system

1 | P a g e BLUETOOTH BASED HOME AUTOMATION SYSTEM

Institute of Tech. & Science Indore

ACKNOWLEDGEMENT

We are very grateful to our project guide of Electronics &

Instrumentation Engineering, SGSITS Indore,Prof., who laid the time

bound program for the successful completion of this project. He initiated

our thoughts and extended timely suggestions and for his technical

support and valuable suggestions for which we are deeply indebted to

him. We are grateful to him for his comments and insights in the

preparation of this project report without which this report would not

have been completed.

We thank sincerely and profusely to all staff members of our Department

of our Institute for their valuable help and guidance.

We also express our gratitude to the Institute Management to all those

who have indirectly help us in the successful completion of this project.

Last but not the last, we are deeply indebted to our parents for what we

are today, because this project report would not have been a reality

without their love and support.

Yours Sincerely, VeEr Singh Shakya

Electronics & Inst.



Table of Content

1. Overview of Project 1.1 Introduction

1.2 Block diagram 1.3 Project Modules

2. Hardware Description 2.1 Microcontroller 2.1.1 ATMEGA 8 2.1.2 Block Diagram 2.1.3 Features 2.1.4 Pin diagram 2.1.5 Pin description 2.1.6 Special Function Registers 2.1.7 Memory Organization 2.1.7.1 Program Memory 2.1.7.2 Data Memory 2.1.8 Watchdog Timer

2.2 BLUETOOTH MODULE (HC-05):Overview 2.2.1 Specifications 2.2.2 Pin out configuration 2.2.3 Typical Application Circuit 2.2.4 Pairing 2.2.5 Hc-05 Bluetooth module working voltage 2.2.6 Serial communication

2.3 Driver IC 2.3.1 ULN2003 Darlington Transistor Arrays 2.3.2 Simplified Schematics 2.3.3 Functional Block Diagram 2.3.4 Pin diagram 2.3.5 Inductive Load Drive 2.3.6 Resistive Load Drive



2.4 Switches 2.4.1Relay

2.5 Connector

2.6 Aurdino burner

2.7Power supply

3. Software Introduction

3.1 PROTEUS 3.2 KEIL 3.3 VP812 3.4 Android App

4. Serial communication-Introduction Serial communication in 89s52 4.1 Selection of baud rate 4.2 SBUF register 4.2.1 Configuration of SCON register 4.2.2 SM0, SM1 4.3 REN (receive enable) 4.4 TI (transmit interrupt) 4.5 RI (receive interrupt) 4.6 Steps for transmitting and receiving of character 4.6.1The steps that 8051 goes through in transmitting a character via TxD 4.6.2Programming the 8051 to transfer character bytes serially 4.6.3Importance of TI Flag 4.6.4Programming the 8051 to receive character bytes serially

5. Program 5.1 PROGRAM CODES 5.2 Program detail



6. Circuit diagram & Component List 6.1 Component list

7. Problem descriptions

8. Advantages & Disadvantages 8.1 Advantages 8.2 Disadvantages

9. Future scope 10. Conclusion References



1. OVERVIEW OF PROJECT

1.1 INTRODUCTION:

Automation involves introducing a degree of computerized or automatic control

to certain electrical and electronic systems in a building. These include lighting,

temperature control, etc. The past decade has seen significant advancement in

the field of consumer electronics. Various intelligent appliances such as cellular

phone, air conditioners, home security devices, home theaters, etc., are set to

realize the concept of a smart home. They have given rise to a Personal Area

Network in home environment, where all these appliances can be interconnected

and monitored using a single controller.

This project demonstrates an automation system which contains a remote mobile

host controller and several client modules (eg.Office, home appliances). The client

modules communicate with the host controller through a wireless device such as

a Bluetooth enabled mobile phone, in this case, an android based Smart phone.

Although automation today is not a new thing but most advanced home

automation systems in existence today require a big and expensive change of

infrastructure. We have proposed an automation system that can control

appliances like TVs, Fan, Tube lights from an android mobile using Bluetooth. In

this a low cost secure cell phone based, flexible automation system is introduced.

Devices are connected to the microcontroller based switching circuit.



The communication between the cell phone and the microcontroller board is

wireless. Additional devices can be connected into the system with little

modifications. The phone will be Android OS based phone. The switching circuit

will be having microcontroller coding to control the electronics devices like fans

and lights etc. 8-bit microcontroller board based on the ATMEGA 8 and the HC-05

Bluetooth module is used. It supports wireless serial communication over

Bluetooth. This board has 32 digital input and output ports.

The atmega 8 can be programmed using the microcontroller’s high-level

interactive embedded C language. The Bluetooth antenna in our module picks up

the packets sent from the cell phone. Subsequently, these packets containing the

device status as commands are pipelined through atmega8 microcontroller and

the designed analogue circuitry according to the definition of each output.

Different home or office appliances are connected to the digital output ports of

the circuit via relays to provide sufficiently high currents and voltage

compatibility. For test purposes, 25W, 240V lamps will be used.

We send commands from an application which is developed in phone to turn

ON/OFF a device. A feedback circuit has been designed and implemented to

indicate the devices actual status after it receives the command (ON/OFF) from

the cell phone. Once the command has been sent to turn ON a device, the

feedback circuit senses the current and gives an output signal by turning ON a

respective led on the switching circuitry indicating that the device is ON.

Otherwise, the device is malfunctioning indicating that the command was not



executed successfully. We can also operate the appliances of Home or Office in

Bluetooth range area.

1.2 Block diagram:-

Figure 1: Block diagram of Bluetooth based home automation

In this block diagram communication is in both direction between android mobile

and Bluetooth module. This communication is done one by one only one at a

time. This communication is called half duplex.

Feedback is done by getting 220v.feedback circuitry is so deigned that

microcontroller can easily sense.

1.3 Project Modules :-

The project can be better described by dividing it into two categories, namely, 1. Hardware 2. Software



2. Hardware Description

2.1 Microcontroller:-Micro controller is just like a small computer but the basic

difference comes in size and memory. These have CPU, RAM, ROM, I/O and

timers are all on a single chip. It means you don’t need any extra device to make it

functional like with a micro-processor. Generally this microcontroller is used

where a specific task is needed to do. So fixed amount of on-chip ROM, RAM, and

number

2.1.1.ATMEGA 8:- The Atmel AVR ATmega8 is a low-power CMOS 8-bit

microcontroller based on the AVR RISC architecture. By executing powerful

instructions in a single clock cycle, the ATmega8 achieves throughputs

approaching 1MIPS per MHz, allowing the system designer to optimize power

consumption versus processing speed.

The Atmel®AVR® core combines a rich instruction set with 32 general purpose

working registers. All the 32 registers are directly connected to the Arithmetic

Logic Unit (ALU), allowing two independent registers to be accessed in one single

instruction executed in one clock cycle. The resulting architecture is more code

efficient while achieving throughputs up to ten times faster than conventional

CISC microcontrollers.



2.1.2. Block Diagram:-

Figure 2: Block diagram of atmega 8 micro controller



2.1.3. Features

I. High-performance, Low-power Atmel®AVR® 8-bit Microcontroller

II. Advanced RISC Architecture

III. 130 Powerful Instructions – Most Single-clock Cycle Execution

IV. 32 × 8 General Purpose Working Registers

V. Fully Static Operation

VI. Up to 16MIPS Throughput at 16MHz

VII. On-chip 2-cycle Multiplier

VIII. High Endurance Non-volatile Memory segments

IX. 8Kbytes of In-System Self-programmable Flash program memory

X. 512Bytes EEPROM

XI. 1Kbyte Internal SRAM

XII. Write/Erase Cycles: 10,000 Flash/100,000 EEPROM

XIII. Data retention: 20 years at 85°C/100 years at 25°C(1)

XIV. Optional Boot Code Section with Independent Lock Bits

XV. In-System Programming by On-chip Boot Program

XVI. True Read-While-Write Operation

– Programming Lock for Software Security



2.1.4 Pin diagram:-

Fig. 3: Pin Diagram of ATMEGA 8

2.1.5. Pin description:-

VCC Digital supply voltage.

GND Ground.



Port B (PB7..PB0) XTAL1/XTAL2/TOSC1/ TOSC2

Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for

each bit). The Port B output buffers have symmetrical drive characteristics with

both high sink and source capability. As inputs, Port B pins that are externally

pulled low will source current if the pull-up resistors are activated. The Port B pins

are tri-stated when a reset condition becomes active, even if the clock is not

running. Depending on the clock selection fuse settings, PB6 can be used as input

to the inverting Oscillator amplifier and input to the internal clock operating

circuit. Depending on the clock selection fuse settings, PB7 can be used as output

from the inverting Oscillator amplifier.

If the Internal Calibrated RC Oscillator is used as chip clock source, PB7..6 is used

as TOSC2..1 input for the Asynchronous Timer/Counter2 if the AS2 bit in ASSR is

set.

Port C (PC5..PC0) Port C is an 7-bit bi-directional I/O port with internal pull-up resistors (selected

for each bit). The Port C output buffers have symmetrical drive characteristics

with both high sink and source capability. As inputs, Port C pins that are externally

pulled low will source current if the pull-up resistors are activated. The Port C pins

are tri-stated when a reset condition becomes active, even if the clock is not

running.

PC6/RESET If the RSTDISBL Fuse is programmed, PC6 is used as an I/O pin. Note that the

electrical characteristics of PC6 differ from those of the other pins of Port C.



If the RSTDISBL Fuse is unprogrammed, PC6 is used as a Reset input. A low level

on this pin for longer than the minimum pulse length will generate a Reset, even if

the clock is not running. The minimum pulse length is given in Table 15 on page

38. Shorter pulses are not guaranteed to generate a Reset. The various special

features of Port C are elaborated on page 61.

Port D (PD7..PD0) Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected

for each bit). The Port D output buffers have symmetrical drive characteristics

with both high sink and source capability. As inputs, Port D pins that are

externally pulled low will source current if the pull-up resistors are activated. The

Port D pins are tri-stated when a reset condition becomes active, even if the clock

is not running. Port D also serves the functions of various special features of the

ATmega8

RESET Reset input. A low level on this pin for longer than the minimum pulse length will

generate a reset, even if the clock is not running. The minimum pulse length is

given in Table 15. Shorter pulses are not guaranteed to generate a reset.

AVCC AVCC is the supply voltage pin for the A/D Converter, Port C (3..0), and ADC

(7..6). It should be externally connected to VCC, even if the ADC is not used. If the

ADC is used, it should be connected to VCC through a low-pass filter. Note that

Port C (5..4) use digital supply voltage, VCC.



AREF AREF is the analog reference pin for the A/D Converter. ADC7..6 (TQFP and QFN/MLF Package Only)

In the TQFP and QFN/MLF package, ADC7..6 serve as analog inputs to the A/D

converter. These pins are powered from the analog supply and serve as 10-bit

ADC channels.

2.2 BLUETOOTH MODULE (HC-05):

Overview: Communication device:-over project is based on wireless

communication between micro controller and mobile phone. But alone micro

controller is not able to communicate directly to the android mobile phone.

Bluetooth Serial module’s operation doesn’t need drive, and can communicate

with the other Bluetooth device that has the serial. But communication between

two Bluetooth modules requires at

Least two conditions:

(1) The communication must be between master and slave.

(2) The password must be correct.

HC-05 module is an easy to use Bluetooth SPP (Serial Port Protocol) module,

designed for transparent wireless serial connection setup. Serial port Bluetooth

module is fully qualified Bluetooth V2.0+EDR (Enhanced Data Rate) 3Mbps

Modulation with complete 2.4GHz radio transceiver and baseband. It uses CSR

Blue core 04‐External single chip Bluetooth system with CMOS technology and



with AFH (Adaptive Frequency Hopping Feature). It has the Foot print as small as

12.7mmx27mm.

HC-05 module is an easy to use Bluetooth SPP (Serial Port Protocol) module,

designed for transparent wireless serial connection setup. Serial port Bluetooth

module is fully qualified Bluetooth V2.0+EDR (Enhanced Data Rate) 3Mbps

Modulation with complete 2.4GHz radio transceiver and baseband Bluetooth

Wireless networks for short range communications have a wide spread usage of

Bluetooth radio transmissions between 2400–2480 MHz Modern mobile devices

embed small, low-powered and cheap integrated chips functioning as short-range

radio transceivers for Bluetooth radio communications. Device pairing,

authentication, encryption and authorization techniques have given recognition

to Bluetooth technology due to its vital security mechanisms.

Different types of Bluetooth applications can be developed using Android

platform architecture using the Bluetooth profiles. The device manufacturers

provide the services using the support of these profiles in their devices to

maintain compatibility for the Bluetooth technology

Fig. 5.HC-05 Bluetooth



2.2.1. Specifications

Hardware features Typical -80dBm sensitivity.

Up to +4dBm RF transmits power.

Low Power 1.8V Operation, 3.3 to 5 V I/O.

PIO control.

UART interface with programmable baud rate.

With integrated antenna.

With edge connector.

Software features Slave default Baud rate: 9600, Data bits:8, Stop bit:1,Parity:No parity.

PIO9 and PIO8 can be connected to red and blue led separately. When master

and slave are paired, red and blue led blinks 1time/2s in interval, while

disconnected only blue led blinks 2times/s.

Auto connects to the last device on power as default.

Permit pairing device to connect as default.

Auto pairing PINCODE:”1234” as default.

Auto reconnect in 30 min when disconnected as a result of beyond the

range of connection.

2.2.2. Pin out configuration

Figure 6: Pin-out of HC-05



2.2.3. Typical Application Circuit:

2.2.4. Pairing: After connect the Bluetooth module, scan for new devices from the Android phone and you will find the module with the device name “HC-05”, after that, click to connect, if some message appears asking about “Pairing code” just put “1234” as default code. BLUE LED = ACTIVE (Blinking 500ms period inactive connection, change 1seg with active connection)

How to get to the standard communication mode

1. Leave free KEY, don’t connect it to VDD neither GND.

2. Supply power to the module. Then the module will enter to communication

mode. It can be used for pairing.



2.2.5. HC-05 BLUETOOTH MODULE WORKING VOLTAGE:- The Bluetooth module HC-05 is used to receive & transmit data between

Bluetooth device and MCU. It requires power supply from 3.3V to 5V.

2.2.6. SERIAL COMMUNICATION:-

To transfer to a device located many meters away, the serial method is used. The

data is sent one bit at a time. Here not 8bit data is send 2 extra bit are send along

with it .this two bit are called start bit and stop bit. These two bit are used so

synchronization can be done between transmitter and receiver.

2.3 Driver IC:

2.3.1 ULN2003 Darlington Transistor Arrays:-

The ULN2003 device is a high-voltage, high- current Darlington transistor array.

The device consists of eight NPN Darlington pairs that feature high-voltage

outputs with common-cathode clamp diodes for switching inductive loads. The

collector-current rating of each Darlington pair is 500 mA. The Darlington pairs

may be connected in parallel for higher current capability.

2.3.2 Simplified Schematics

Fig. 7.Simplified Schematics of ULN2003



2.3.3. Functional Block Diagram:

Fig. 8.Functional block diagram of ULN2003

Each channel of ULN2003 consists of Darlington connected NPN transistors. This

connection creates the effect of a single transistor with a very high current gain.

This can be as high as 10,000 A/A at certain currents. The very high gain allows for

high output current drive with a very low input current, essentially equating to

operation with low GPIO voltages. The GPIO voltage is converted to base current

via the 2.7 kΩ resistor connected between the input and base of the pre-driver

Darlington NPN. The 7.2 kΩ & 3.0 kΩ resistors connected between the base and

emitter of each respective NPN act as pull-downs and suppress the amount of

leakage that may occur from the input. The diodes connected between the output

and COM pin is used to suppress the kick-back voltage from an inductive load that

is excited when the NPN drivers are turned off (stop sinking) and the stored

energy in the coils causes a reverse current to flow into the coil supply via the

kick-back diode. In normal operation the diodes on base and collector pins to

emitter will be reversed biased. If these diode are forward biased, internal



parasitic NPN transistors will draw (a nearly equal) current from other (nearby)

device pins.

2.3.4 Pin diagram:-

Fig. 9.pin diaygram of uln 2003 ULN2003 Darlington Transistor Arrays pin no 10 can be used for inductive or non-

inductive load. These high output current driver pin can sink 500mA.If

requirement of more current then two pin can also be connected parallel. Parallel



connection must be done both input and output. Input and output current will

multiply according to number of input and output connected parallel.

2.3.5 Inductive Load Drive

When the COM pin is tied to the coil supply voltage, ULN2803A is able to drive

inductive loads and suppress the Kick-back voltage via the internal freewheeling

diodes.

2.3.6 Resistive Load Drive

When driving a resistive load, a pull-up resistor is needed in order for ULN2003 to

sink current and for there to be a logic high level. The COM pin can be left floating

for these applications

2.4 Switches:-

Switches are used for connecting or disconnecting electrical circuit. Many types of

switches are there. Some are operate mechanically or electrically. Some types are

SPST, SPDT, DPST and DPDT in case of switch. SPST stands for single pole single

through, SPDT stands for single pole double through, DPST stands for double pole

single through and DPDT stands for double pole double through, In relays points

are defines by NO, NC. NO stand for normally on and NC stands for normally off.

2.4.1 Relay:-

Relays are electromagnetic switch. Which can be turn on and off by Appling

electrical current. Working voltage is printed on the relay. In this project we are



using 6volt relay. Many relay use an electromagnet to mechanically operate a

switch.

Fig.10. .Relays

2.5 Connector:-

Connectors are used for joining two wires temporally by using connector big

circuit can be divided and after completion they can rejoin. Now a day’s every

time inverter circuited can be removed out without using de soldering.

2.6 Aurdino burner:-

Arduino is common term for a software company, project, and user community,

that designs and manufactures computer open-source hardware, open-source

software, and microcontroller-based kits for building digital devices and

interactive objects that can sense and control physical devices.[1]

https://en.wikipedia.org/wiki/Open-source_hardware

https://en.wikipedia.org/wiki/Open-source_software


https://en.wikipedia.org/wiki/Microcontroller

https://en.wikipedia.org/wiki/Arduino#cite_note-1



Arduino is common term for a software company, project, and user community,

that designs and manufactures computer open-source hardware, open-source

software, and microcontroller-based kits for building digital devices and

interactive objects that can sense and control physical devices.[1]

The project is based on microcontroller board designs, produced by several

vendors, using various microcontrollers. These systems provide sets of digital and

analog I/O pins that can interface to various expansion boards (termed shields)

and other circuits. The boards feature serial communication interfaces, including

Universal Serial Bus (USB) on some models, for loading programs from personal

computers. For programming the microcontrollers, the Arduino project provides

an integrated development environment(IDE) based on a programming language

named Processing, which also supports the languages C and C++.

https://en.wikipedia.org/wiki/Open-source_hardware



https://en.wikipedia.org/wiki/Microcontroller


https://en.wikipedia.org/wiki/I/O

https://en.wikipedia.org/wiki/USB

https://en.wikipedia.org/wiki/Integrated_development_environment

https://en.wikipedia.org/wiki/Processing_(programming_language)

https://en.wikipedia.org/wiki/C_(programming_language)

https://en.wikipedia.org/wiki/C%2B%2B



The first Arduino was introduced in 2005, aiming to provide a low cost, easy way

for novices and professionals to create devices that interact with their

environment using sensors and actuators. Common examples of such devices

intended for beginner hobbyists include simple robots, thermostats, and motion

detectors.

Arduino boards are available commercially in preassembled form, or as do-it-

yourself kits. The hardware design specifications are openly available, allowing

the Arduino boards to be produced by anyone. Adafruit Industries estimated in

mid-2011 that over 300,000 official Arduinos had been commercially

produced,[2] and in 2013 that 700,000 official boards were in users' hands.

The project is based on microcontroller board designs, produced by several

vendors, using various microcontrollers. These systems provide sets of digital and

analog I/O pins that can interface to various expansion boards (termed shields)

and other circuits. The boards feature serial communication interfaces, including

Universal Serial Bus (USB) on some models, for loading programs from personal

computers. For programming the microcontrollers, the Arduino project provides

an integrated development environment(IDE) based on a programming language

named Processing, which also supports the languages C and C++.

The first Arduino was introduced in 2005, aiming to provide a low cost, easy way

for novices and professionals to create devices that interact with their

environment using sensors and actuators. Common examples of such devices

intended for beginner hobbyists include simple robots, thermostats, and motion

detectors.

https://en.wikipedia.org/wiki/Sensor

https://en.wikipedia.org/wiki/Actuator

https://en.wikipedia.org/wiki/Robot

https://en.wikipedia.org/wiki/Thermostat

https://en.wikipedia.org/wiki/Do-it-yourself


https://en.wikipedia.org/wiki/Adafruit_Industries


https://en.wikipedia.org/wiki/I/O

https://en.wikipedia.org/wiki/USB

https://en.wikipedia.org/wiki/Integrated_development_environment

https://en.wikipedia.org/wiki/Processing_(programming_language)

https://en.wikipedia.org/wiki/C_(programming_language)

https://en.wikipedia.org/wiki/C%2B%2B

https://en.wikipedia.org/wiki/Sensor

https://en.wikipedia.org/wiki/Actuator

https://en.wikipedia.org/wiki/Robot

https://en.wikipedia.org/wiki/Thermostat



Arduino boards are available commercially in preassembled form, or as do-it-

yourself kits. The hardware design specifications are openly available, allowing

the Arduino boards to be produced by anyone. Adafruit Industries estimated in

mid-2011 that over 300,000 official Arduinos had been commercially

produced,[2] and in 2013 that 700,000 official boards were in users' hands.

2.7 LCD:-

LCD (Liquid Crystal Display) screen is an electronic display module and find a wide

range of applications. A 16x2 LCD display is very basic module and is very

commonly used in various devices and circuits. These modules are preferred

over seven segments and other multi segment LEDs. The reasons being: LCDs are

economical; easily programmable; have no limitation of displaying special &

even custom characters (unlike in seven segments), animations and so on.

A 16x2 LCD means it can display 16 characters per line and there are 2 such lines.

In this LCD each character is displayed in 5x7 pixel matrix. This LCD has two

registers, namely, Command and Data.

The command register stores the command instructions given to the LCD. A

command is an instruction given to LCD to do a predefined task like initializing it,

clearing its screen, setting the cursor position, controlling display etc. The data

register stores the data to be displayed on the LCD. The data is the ASCII value of

the character to be displayed on the LCD. Click to learn more about internal

structure of a LCD.



https://en.wikipedia.org/wiki/Adafruit_Industries


http://www.engineersgarage.com/content/seven-segment-display

http://www.engineersgarage.com/content/led

http://www.engineersgarage.com/microcontroller/8051projects/create-custom-characters-LCD-AT89C51

http://www.engineersgarage.com/microcontroller/8051projects/display-custom-animations-LCD-AT89C51

http://www.engineersgarage.com/insight/how-lcd-works



Pin Diagram:

Pin Description:

Pin No

Function Name

1 Ground (0V) Ground

2 Supply voltage; 5V (4.7V – 5.3V) Vcc

3 Contrast adjustment; through a variable resistor VEE

4 Selects command register when low; and data register when high

Register Select

5 Low to write to the register; High to read from the register Read/write

6 Sends data to data pins when a high to low pulse is given Enable

7

8-bit data pins DB0

8 DB1



9 DB2

10 DB3

11 DB4

12 DB5

13 DB6

14 DB7

15 Backlight VCC (5V) Led+

16 Backlight Ground (0V) Led-

3. Software

INTRODUCTION: Electronic design automation (EDA or ECAD) is a category

of software tools for designing electronic systems such as printed circuit boards

and integrated circuits. The tools work together in a design flow that chip

designers use to design and analyze entire semiconductor chips. The various

software’s used are:

3.1 EAGLE:-

EAGLE stands for, Easily Applicable Graphical Layout Editor in English

and, Einfach anzuwendender grafischer Layout-Editor inGerman. It is designed

and developed by CadSoft Computer GmbH and is a flexible, expandable and

scriptable, electronic design automation (EDA) application with schematic capture

editor, printed circuit board (PCB) layout editor, auto-router and computer-aided

manufacturing (CAM) and bill of materials (BOM) tools. Premier Farnell bought

EAGLE in 2008.[1]

https://en.wikipedia.org/wiki/German_language

https://en.wikipedia.org/wiki/CadSoft_Computer_GmbH

https://en.wikipedia.org/wiki/Electronic_design_automation

https://en.wikipedia.org/wiki/Printed_circuit_board

https://en.wikipedia.org/wiki/Computer-aided_manufacturing

https://en.wikipedia.org/wiki/Computer-aided_manufacturing

https://en.wikipedia.org/wiki/Bill_of_materials

https://en.wikipedia.org/wiki/Premier_Farnell

https://en.wikipedia.org/wiki/EAGLE_(program)#cite_note-1





3. 2 Serial communication in atmega8 SERIAL COMMUNICATION-INTRODUCTION: Serial is a device

communication protocol that is standard on almost every PC. Do not confuse it

with universal serial bus (USB). Most computers include two EIA-232 based serial

ports. Serial is also a common communication protocol for instrumentation in

many devices, and numerous GPIB-compatible devices come with an EIA-232

port. Furthermore, you can use serial communication for data acquisition in

conjunction with a remote sampling device

5. Program

5.1 PROGRAM CODES:

#include <reg52.h>

#define OUT_PORT1 P2

#define HIGH 1

sbit IN = P2^0;

sbit IN2 = P2^1;

sbit CFL1 = OUT_PORT1^5;





void com3();

void com2();

void com1();

void delay(const unsigned int ms);

unsigned char z;

unsigned char Mess1[]="SW OFF,";

unsigned char Mess2[]="SW ONN,";

unsigned char Mess3[]="Access Denied,";\

void main()

{

unsigned char mybyte;

unsigned char old;

unsigned char rx;

TMOD=0x20; //use Timer 1, mode 2

TH1=0xFD; //9600 baud rate

SCON=0x50;

TR1=1; //start timer

while (1) { //repeat forever

while (RI==0); //wait to receive; //save value



old = SBUF;

RI=0;

delay(30);

rx = SBUF;

RI=0;

if (old = rx)

{

mybyte = old;

}

else

{

mybyte = rx;

}

if(mybyte==0x01)

{

CFL1=CFL1^HIGH;//toggle bit

mybyte=0xff;

old =0xff;

if(IN2==0)



{ //check switch on

com2(); //send status

}

else

{

com1();

}

}

else if(mybyte==0x02)

{

CFL2=CFL2^HIGH;

mybyte=0xff;

if(IN==0) {

com2();

}

else

{



com1();

}

}

else if(mybyte==0x03)

{

CFL3=CFL3^HIGH;

mybyte=0xff;

if(CFL3==0) {

com1();

}

else

{

com2();

}

}

else if(mybyte==0x04) // check port 1 value

{



SBUF=P2;

while(TI==0); //wait for transmit

TI=0;

}


{

if(IN==0)

{ //check switch on


}

else

{

com1();

}

}


{



if(IN2==0)

{ //check switch on


}

else

{

com1();

}

}

else

{

com3();

}

}

}

void com3()

{

for (z=0;z<15;z++) {



SBUF=Mess3[z]; //place value in buffer


TI=0;

}

}

void com2()

{

for (z=0;z<8;z++) {



TI=0;

}

}

void com1()

{

for (z=0;z<8;z++) {





TI=0;

}

}

void delay(const unsigned int ms)

{

unsigned int x, y;

for(x = 0; x<=ms;x++)

{

for(y=0;y<=1275;y++);

}

}

5.2 Program detail 1. #include <reg52.h>:-By using this we define the header file of micro –

controller 89s52.

2. #define OUT_PORT2 P1:-this line is used for defining a port with output

port.



3. SBUF is an 8-bit register used solely for serial communication ¾For a byte

data to be transferred via the Txd line, it must be placed in the SBUF

register .The moment a byte is written into SBUF, it is framed with the start

and stop bits and transferred serially via the Txd line .SBUF holds the byte

of data when it is received by 8051 RxD line .When the bits are received

serially via RxD, the 8051 deframes it by eliminating the stop and start bits,

making a byte out of the data received, and then placing it in SBUF.

4. SCON is an 8-bit register used to program the start bit, stop bit, and data

bits of data framing, among other things.

5. TI (transmit interrupt) When 8051 finishes the transfer of 8-bit character .It

raises TI flag to indicate that it is ready to transfer another byte TI bit is

raised at the beginning of the stop bit.

6. RI (receive interrupt) When 8051 receives data serially via RxD, it gets rid of

the start and stop bits and places the byte in SBUF register It raises the RI

flag bit to indicate that a byte has been received and should be picked up

before it is lost .RI is raised halfway through the stop bit.



6. Circuit diagram & Component List

6.1. Component list:-

S.No Component Name Nos. Required

1 HC-05 Bluetooth module 1

2 ATMEGA8 micro controller IC 1

3 ULN2003 IC 3

4 5V relay 2

5 Crystal 12MHz or 11.0592MHz 1

6 1K Resistor 1

7 22µf or 10µf electrolyte capacitor 2

8 30pf or 22pf ceramic capacitor 2

9 10k resistor network 3

10 7805 IC 2

11 12V battery 2

12 220v to 6v-0-6v step down transformer 1

13 1N4007 diode 3



6.2 Circuit Diagram:

Circuit diagram of main board



Circuit diagram of Relay board





7. Problem description

The various problems & FAQ’s associated with the project are:

7.1. No manual control to switch on and off or in system when

failed:-

In that case we can use a two way switch so if automation system fails than

control given to manual. As the manual control provided unskilled user can

perform his routine control. As shown below.

In fig a two way connection with relay is shown. The control act as a XOR

operation mines that output is one when both input are same. So output is

available when positions of both switches are same.



Fig. 29.Wiring connection to switch

7.2. No confirmation of change of output:-

To overcome this problem programming can be do so that controller can

compare its previous state. So if state of switch not changes than

controller send an error comes or no change.

7.3. No debugging option:-

This can be a very good feature of project i.e. you can check that where

problem comes at hardware or in software. So controller gave all

information about communication.

7.4. Complex user interface:-

User interface must be simple so no need to teach the other every time.

But in similar project interface is complex.



7.5. Different key to on and off:-

In survey it is seen that there are two different key to turn n and off

appliances. But if in programming toggle of bit is done then more

automation can be done in this project.

7.6. Restart power at every new pairing of device:-

In HV-05 Bluetooth module if a device is parried then this configuration is

save. So at every new device pairing needs restart of circuit power. This

problem can be removed if we use a feature of HC-05 Bluetooth i.e. “key”

this a pin in Bluetooth that can remove all paired detail when this pin

high pulses. So connection of this pin with micro controller can rest the

pairing.

7.7. Large change in house wiring:-

In similar project the automation done by mobile only so all connection

needs to change in wiring and removal of button connection is needed

.So to avoid this circuit is so design as sown in problem 1 solution.

7.8. Security of hacking control:-

The Bluetooth connection kept open so other con connect and take

control. so the master user must connect to Bluetooth and removal of

pair info must by master controller by software control.



8. Advantages & Disadvantages

8.1 Advantages

1. Wireless control:-

By using this project wireless control can be within the hands of user.

2. Monitoring:-

This circuit allow monitoring of all appliance within range of communication

with Bluetooth.

3. Status checking :-

When user doesn’t know appliances is on off then user can only check the

status only.

4. Confirmation of changing switch state:-

When switch is press ten two status will be shown on mobile phone i.e. old

status and new status

5. Manual control:-

Manual control is given so an unskilled user can be change the current

status.

8.2. Disadvantages:-

1. Bluetooth range:-



It is good to use Bluetooth for automation but automation is kept within a

range 0f 10-30 metres. So control can be achieved from outside range.

2. Connection:-

Application must be connected after disconnection from Bluetooth.

3. configuration of application software:-

If new user want to connect then first download application software and

then code must be enter and more configuration must be done.

9. FUTURE SCOPE

This project can be further developed by integrating it with the internet to

monitor your home while sitting in a remote area. By doing this, one can keep an

eye on his or her home through an internet connected to the user’s mobile phone

or PC or laptop. This will not only improve the security of your home in this

modern day world but will also assist in conservation of energy like if you left any

home appliance switched on by mistake, then you can check the status of the

appliance on the graphical interface made on your mobile and can switch it off

using the internet connectivity.



10. CONCLUSION

In conclusion, this low cost system is designed to improve the standard living in

home. The remote control function by smart phone provides help and assistance

especially to disabled and elderly. In order to provide safety protection to the

user, a low voltage activating switches is replaced current electrical switches.

Moreover, implementation of wireless Bluetooth connection in control board

allows the system install in more simple way. The control board is directly

installed beside the electrical switches whereby the switching connection is

controlled by relay.

Furthermore, flexible types of connections are designed as backup connections to

the system. The connected GUIs are synchronized to the control board. They

indicate the real-time switches status. The system is designed in user-friendly

interface. The easy to use interface on Window and Android GUI provides simple

control by the elderly and disabled people.

For future work, the Window GUI will be implemented with speech recognition

voice control. The android GUI will be implemented as a remote Bluetooth



microphone to the Window GUI. All the voice signal inputs to the smart phone

will be transmitted to the Window GUI for signal processing. Also, the push

buttons implemented in low voltage activating switches will be replaced by

capacitive sensing switches. All the future work is expected without spend extra

cost, even one cent from the current system.

REFERENCES

1. Electronics for you magine June 2013

Keil µvision IDE, http://www.keil.com/uvision.

2. www.vp812.com

3. Serial Bluetooth Module, Tiny OS Electronics, http://www.tinyosshop.com

4. AT89s52 8 bit Microcontroller, ATMEL Corporations,

http://www.atmel.com3.

5. The official Bluetooth website from Bluetooth SIG:

http://www.bluetooth.com

http://www.keil.com/uvision

http://www.vp812.com/

http://www.tinyosshop.com/

http://www.atmel.com3/



6. The 8051 microcontroller and embedded systems by Muhammad Ali

Mazidi and Janice Gillispie Mazidi.