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Advanced low cost voice recognition based smart home/office
automation using android
ABSTRACT
Now a day’s so many useful technologies are coming out to make our life style more comfort,
luxurious and secure. Especially in mobile field so many application are being developed to give
us more information and entertainment .this project is designed with combination of two latest
and most demanding technologies that are Android and Embedded Systems.
Android is a Linux based operating system designed primarily for mobile devices and it is a open
source .There are so many applications are already developed on Android and many applications
are being developed at free of cost for its users. We can also develop our own customized
applications with free of cost or with minimum cost according to our requirements.
In this project we are using an application to control electrical appliances like fan, lights and
water pump motors in home or office with voice recognition. Whenever we operate this
application, it will wait for voice input for some time and sends recognized voice commands to
our controlling system through Bluetooth.
At controlling system side we have Bluetooth module, micro controller and load controlling
circuits. Whenever this blue tooth module receives command from android application then it
transfers this command to micro controller. Micro controller will control the respective loads
depends upon the command it received. This is very safe and secure and also we can control
many loads without getting confused by adding specific names for each load.

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CHAPTER: 1
INTRODUCTION
1.1INTRODUCTION
The “Home Automation” concept has existed for many years. The terms “Smart
Home”, “Intelligent Home” followed and has been used to introduce the concept of networking
appliances and devices in the house. Home automation Systems (HASs) represents a great
opportunity in creating new fields in engineering, architecture. The capabilities of Bluetooth are
more than enough to be implemented in the design. Also, most of the current laptop/notebook or
cell phones are come with built-in Bluetooth adapter. It will indirectly reduce the cost of this
system. Due to the advancement of wireless technology, there are several different of
connections are introduced such as GSM, WIFI, ZIGBEE, and Bluetooth.
Each of the connection has their own unique specifications and applications. Among the
four popular wireless connections that often implemented in HAS project, Bluetooth is being
chosen with its suitable capability. Bluetooth with globally available frequencies of 2400Hz is
able to provide connectivity up to 100 meters at speed of up to 3Mbps depending on the
Bluetooth device
This application will be used to control the AC loads according to your command give
from the android app. Especially in mobile field so many application are being developed to give
us more information and entertainment. This project is designed with combination of two latest
and most demanding technologies that are Android and Embedded Systems. To do this we are
using this Android App, which is open source and easy to install Bluetooth SPP software and
Bluetooth module at receiver side to receive the data.
Android is a Linux based operating system designed primarily for mobile devices and it
is a open source .There are so many applications are already developed on Android and many
applications are being developed at free of cost for its users .

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1.2PROBLEM OUTLINE
In the earlier days the loads are controlled by using switches by going to the near of switch
boards. As technology increases there were wireless technologies developed like IR, RF, and
ZIGBEE etc. But these all technologies need a separate remote like transmitter object to operate
the loads.
1.3 OBJECTIVE OF THE PROJECT
The most advanced technology is Bluetooth. And the technology based on Android OS. By
using this technology, we just need and android mobile and there is no separate remote. By using
the mobile itself you can send voice commands to the Bluetooth module. The switches status is
synchronized in all the control system whereby every user interface indicates the real time
existing switches status. The system intended to control electrical appliances and devices in
house with relatively low cost design, user-friendly interface and ease of installation.
1.4 SCOPE OF STUDY:
The scope of study which is needed for the completion of this project involves the
following criteria:
1. Architecture of 8051 knowledge
2. 8051 programming in C language.
3. The study of the serial communication.
4. Interfacing loads with microcontroller.
5. The circuitry and devices that is needed to construct the devices and establish the necessary
communication between the devices.
6. Interfacing Bluetooth with microcontroller

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CHAPTER: 2
INTRODUCTION TO EMBEDDED SYSTEMS
An embedded system can be defined as a computing device that does a specific focused
job. Appliances such as the air-conditioner, VCD player, DVD player, printer, fax machine,
mobile phone etc. are examples of embedded systems. Each of these appliances will have a
processor and special hardware to meet the specific requirement of the application along with the
embedded software that is executed by the processor for meeting that specific requirement. The
embedded software is also called “firm ware”. The desktop/laptop computer is a general purpose
computer. You can use it for a variety of applications such as playing games, word processing,
accounting, software development and so on. In contrast, the software in the embedded systems
is always fixed listed below:
Embedded systems do a very specific task, they cannot be programmed to do different things.
Embedded systems have very limited resources, particularly the memory. Generally, they do not
have secondary storage devices such as the CDROM or the floppy disk. Embedded systems have
to work against some deadlines. A specific job has to be completed within a specific time. In
some embedded systems, called real-time systems, the deadlines are stringent. Missing a
deadline may cause a catastrophe-loss of life or damage to property. Embedded systems are
constrained for power. As many embedded systems operate through a battery, the power
consumption has to be very low.
Some embedded systems have to operate in extreme environmental conditions such as very high
temperatures and humidity.
Application Areas:
Nearly 99 per cent of the processors manufactured end up in embedded systems. The
embedded system market is one of the highest growth areas as these systems are used in very
market segment- consumer electronics, office automation, industrial automation, biomedical
engineering, wireless communication, data communication, telecommunications, transportation,
military and so on.

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Consumer appliances:
At home we use a number of embedded systems which include digital camera, digital
diary, DVD player, electronic toys, microwave oven, remote controls for TV and air-conditioner,
VCO player, video game consoles, video recorders etc. Today’s high-tech car has about 20
embedded systems for transmission control, engine spark control, air-conditioning, navigation
etc. Even wristwatches are now becoming embedded systems. The palmtops are powerful
embedded systems using which we can carry out many general-purpose tasks such as playing
games and word processing.
Office automation:
The office automation products using embedded systems are copying machine, fax
machine, key telephone, modem, printer, scanner etc.
Industrial automation:
Today a lot of industries use embedded systems for process control. These include
pharmaceutical, cement, sugar, oil exploration, nuclear energy, electricity generation and
transmission. The embedded systems for industrial use are designed to carry out specific tasks
such as monitoring the temperature, pressure, humidity, voltage, current etc., and then take
appropriate action based on the monitored levels to control other devices or to send information
to a centralized monitoring station. In hazardous industrial environment, where human presence
has to be avoided, robots are used, which are programmed to do specific jobs. The robots are
now becoming very powerful and carry out many interesting and complicated tasks such as
hardware assembly.
Medical electronics:
Almost every medical equipment in the hospital is an embedded system. These
equipments include diagnostic aids such as ECG, EEG, blood pressure measuring devices, X-ray
scanners; equipment used in blood analysis, radiation, colonoscopy, endoscopy etc.
Developments in medical electronics have paved way for more accurate diagnosis of diseases.

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Computer networking: Computer networking products such as bridges, routers, Integrated
Services Digital Networks (ISDN), Asynchronous Transfer Mode (ATM), X.25 and frame relay
switches are embedded systems which implement the necessary data communication protocols.
For example, a router interconnects two networks. The two networks may be running different
protocol stacks. The router’s function is to obtain the data packets from incoming pores, analyze
the packets and send them towards the destination after doing necessary protocol conversion.
Most networking equipments, other than the end systems (desktop computers) we use to access
the networks, are embedded systems.
Telecommunications:
In the field of telecommunications, the embedded systems can be categorized as
subscriber terminals and network equipment. The subscriber terminals such as key telephones,
ISDN phones, terminal adapters, web cameras are embedded systems. The network equipment
includes multiplexers, multiple access systems, Packet Assemblers Dissemblers (PADs),
sate11ite modems etc. IP phone, IP gateway, IP gatekeeper etc. are the latest embedded systems
that provide very low-cost voice communication over the Internet.
Wireless technologies:
Advances in mobile communications are paving way for many interesting applications
using embedded systems. The mobile phone is one of the marvels of the last decade of the 20’h
century. It is a very powerful embedded system that provides voice communication while we are
on the move. The Personal Digital Assistants and the palmtops can now be used to access
multimedia services over the Internet. Mobile communication infrastructure such as base station
controllers, mobile switching centers are also powerful embedded systems.
Insemination:
Testing and measurement are the fundamental requirements in all scientific and
engineering activities. The measuring equipment we use in laboratories to measure parameters
such as weight, temperature, pressure, humidity, voltage, current etc. are all embedded systems.
Test equipment such as oscilloscope, spectrum analyzer, logic analyzer, protocol analyzer, radio
communication test set etc. are embedded systems built around powerful processors. Thank to
miniaturization, the test and measuring equipment are now becoming portable facilitating easy
testing and measurement in the field by field-personnel.

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Security:
Security of persons and information has always been a major issue. We need to protect
our homes and offices; and also the information we transmit and store. Developing embedded
systems for security applications is one of the most lucrative businesses nowadays. Security
devices at homes, offices, airports etc. for authentication and verification are embedded systems.
Encryption devices are nearly 99 per cent of the processors that are manufactured end up in~
embedded systems. Embedded systems find applications in every industrial segment- consumer
electronics, transportation, avionics, biomedical engineering, manufacturing, process control and
industrial automation, data communication, telecommunication, defense, security etc. Used to
encrypt the data/voice being transmitted on communication links such as telephone lines.
Biometric systems using fingerprint and face recognition are now being extensively used for user
authentication in banking applications as well as for access control in high security buildings.
Finance:
Financial dealing through cash and cheques are now slowly paving way for transactions
using smart cards and ATM (Automatic Teller Machine, also expanded as Any Time Money)
machines. Smart card, of the size of a credit card, has a small micro-controller and memory; and
it interacts with the smart card reader! ATM machine and acts as an electronic wallet. Smart card
technology has the capability of ushering in a cashless society. Well, the list goes on. It is no
exaggeration to say that eyes wherever you go, you can see, or at least feel, the work of an
embedded system!

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CHAPTER: 3
HARDWARE IMPLEMENTATION OF THE PROJECT
This chapter briefly explains about the Hardware Implementation of the project. It
discusses the design and working of the design with the help of block diagram and circuit
diagram and explanation of circuit diagram in detail. It explains the features, timer programming,
serial communication, interrupts of AT89S52 microcontroller. It also explains the various
modules used in this project.
3.1. Project Design:
The implementation of the project design can be divided in two parts.
1. Hardware implementation
2. Firmware implementation.
Hardware implementation deals in drawing the schematic on the plane paper according to the
application, testing the schematic design over the breadboard using the various IC’s to find if the
design meets the objective, carrying out the PCB layout of the schematic tested on breadboard,
finally preparing the board and testing the designed hardware.
The firmware part deals in programming the microcontroller so that it can control the
operation of the IC’s used in the implementation.
INTRODUCTIONTO MICROCONTROLLER:
Based on the Processor side Embedded Systems is mainly divided into 3 types
1. Micro Processor: - are for general purpose e.g. our personal computer
2. Micro Controller: - are for specific applications, because of cheaper cost we will go for these
3. DSP (Digital Signal Processor):- are for high and sensitive application purpose
MICROCONTROLLER VERSUS MICROPROCESSOR:
A system designer using a general-purpose microprocessor such as the Pentium or the 68040
must add RAM, ROM, I/O ports, and timers externally to make them functional. Although the
addition of external RAM, ROM, and I/O ports makes these systems bulkier and much more

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expensive, they have the advantage of versatility such that the designer can decide on the amount
of RAM, ROM and I/O ports needed to fit the task at hand.
A Microcontroller has a CPU (a microprocessor) in addition to a fixed amount of RAM,
ROM, I/O ports, and a timer all on a single chip. In other words, the processor, the RAM, ROM,
I/O ports and the timer are all embedded together on one chip; therefore, the designer cannot add
any external memory, I/O ports, or timer to it. The fixed amount of on-chip ROM, RAM, and
number of I/O ports in Microcontrollers makes them ideal for many applications in which cost
and space are critical.
GeneralMicro Processor:
1. cpu for computers
2. No RAM, ROM, I/O on CPU chip itself
3. Example : Intel’s x86
Micro Controller:
ADDRESSBUS
Many chipson mother’sboard
I/OPORT TIMER SERIAL COM
PORT
ROM
CPU
General
purpose
micro
processor
RAM
Data bus

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A smaller Computer
On chip RAM, ROM, I/O PORTS……..
Example: Intel 8052 etc….
Microprocessor vs. Microcontroller
Microprocessor Microcontroller
CPU is stand alone RAM, RAM, I/O,
timer are separate
CPU,RAM,ROM,I/O and timer are all on a
single chip
Designer can decide on the amount of
ROM, RAM and I/O ports.
Fix amount of on chip ROM,RAM, I/O
Ports.
Expansive, Versatility For applications in which cost, power and
space are critical
General purpose Single purpose
3.1.1 Block Diagram of the Project and its DescriptionThe block diagram of the
design is as shown in Fig 3.1. It consists of power supply unit, microcontroller, BLUETOOTH
modem, TRIAC, loads and LCD. The brief description of each unit is explained as follows.
BLOCK DIAGRAM:
CPU
Serial
COM
Port
RAM
TimerI/O
PORT
ROM
A sigle Chip

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Bluetoothmodule
M
I
C
R
O
C
O
N
T
R
O
L
L
E
R
RESET
CRYSTAL
OSCILLATOR
TRIAC
DRIVER
TRIAC
DRIVER
TRIAC
DRIVER
TRIAC
DRIVER
TRIAC
TRIAC
TRIAC
TRIAC

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Andriod based phone
3.2. Power Supply:
The input to the circuit is applied from the regulated power supply. The a.c. input i.e.,
230V from the mains supply is step down by the transformer to 12V and is fed to a rectifier. The
output obtained from the rectifier is a pulsating d.c voltage. So in order to get a pure d.c voltage,
the output voltage from the rectifier is fed to a filter to remove any a.c components present even
after rectification. Now, this voltage is given to a voltage regulator to obtain a pure constant dc
voltage.
Fig.2: Components of regulated power supply
3.2.1. Transformer:
The A.C. input available at the mains supply i.e., 230V is to be brought down to the
required voltage level. This is done by a transformer. Thus, a step down transformer is employed
to decrease the voltage to a required level.

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3.2.2. Rectifier:
The output from the transformer is fed to the rectifier. It converts A.C. into pulsating
D.C. In this project, a bridge rectifier is used because of its merits like good stability and full
wave rectification.
3.2.3. Filter:
Capacitive filter is used in this project. It removes the ripples from the output of rectifier
and smoothens the D.C. Output received from this filter is constant until the mains voltage and
load is maintained constant. However, if either of the two is varied, D.C. voltage received at this
point changes. Therefore a regulator is applied at the output stage.
3.2.4. Voltage regulator:
As the name itself implies, it regulates the input applied to it. A voltage regulator is an
electrical regulator designed to automatically maintain a constant voltage level. In this project,
power supply of 5V and 12V are required. In order to obtain these voltage levels, 7805 and 7812
voltage regulators are to be used. The first number 78 represents positive supply and the numbers
05, 12 represent the required output voltage levels.
3.3. Microcontrollers:
Microprocessors and microcontrollers are widely used in embedded systems products.
Microcontroller is a programmable device. A microcontroller has a CPU in addition to a fixed
amount of RAM, ROM, I/O ports and a timer embedded all on a single chip. The fixed amount
of on-chip ROM, RAM and number of I/O ports in microcontrollers makes them ideal for many
applications in which cost and space are critical.
It was popular in the 1980s and early 1990s, but today it has largely been superseded by
a vast range of enhanced devices with 8051-compatible processor cores that are manufactured by
more than 20 independent manufacturers including Atmel, Infineon Technologies and Maxim
Integrated Products.
8051 is an 8-bit processor, meaning that the CPU can work on only 8 bits of data at a
time. Data larger than 8 bits has to be broken into 8-bit pieces to be processed by the CPU. 8051
is available in different memory types such as UV-EPROM, Flash and NV-RAM.

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3.3.1. Features of AT89S52:
 8K Bytes of Re-programmable Flash Memory.
 RAM is 256 bytes.
 4.0V to 5.5V Operating Range.
 Fully Static Operation: 0 Hz to 33 MHz’s
 Three-level Program Memory Lock.
 256 x 8-bit Internal RAM.
 32 programmable I/O Lines.
 Three 16-bit Timer/Counters.
 Eight Interrupt Sources.
 Full Duplex UART Serial Channel.
 Low-power Idle and Power-down Modes.
 Interrupt recovery from power down mode.
 Watchdog timer.
 Dual data pointer.
 Power-off flag.
 Fast programming time.
 Flexible ISP programming (byte and page mode).

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3.3.2. Description:
The AT89s52 is a low-voltage, high-performance CMOS 8-bit microcomputer with 8K
bytes of Flash programmable memory. The device is manufactured using Atmel’s high density
nonvolatile memory technology and is compatible with the industry-standard MCS-51
instruction set. The on chip flash allows the program memory to be reprogrammed in system or
by a conventional non volatile memory programmer. By combining a versatile 8-bit CPU with
Flash on a monolithic chip, the Atmel AT89s52 is a powerful microcomputer, which provides a
highly flexible and cost-effective solution to many embedded control applications.
In addition, the AT89s52 is designed with static logic for operation down to zero
frequency and supports two software selectable power saving modes. The Idle Mode stops the
CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue
functioning. The power-down mode saves the RAM contents but freezes the oscillator disabling
all other chip functions until the next hardware reset.

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Fig.3: Pin diagram of 8051
Fig.4: Block diagram of 8051
Pin description:
3.3.3. Vcc:
Pin 40 provides supply voltage to the chip. The voltage source is +5V.
3.3.4. GND:
Pin 20 is the ground.

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3.3.5. Port 0:
Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink
eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high impedance
inputs. Port 0 can also be configured to be the multiplexed low-order address/data bus during
accesses to external program and data memory. External pull-ups are required during program
verification.
3.3.6. Port 1:
Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output buffers
can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the
internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled
low will source current (IIL) because of the internal pull-ups.
Table 1: Alternate functions of port 1
3.3.7. Port 2:
Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output buffers
can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the
internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled
low will source current (IIL) because of the internal pull-ups.

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3.3.8.Port 3:
Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output buffers
can sink/source four TTL inputs.
Table2: Alternate functions of port3
3.3.9. RST:
Reset input A high on this pin for two machine cycles while the oscillator is running
resets the device. This pin drives high for 98 oscillator periods after the Watchdog times out. The
DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default state
of bit DISRTO, the RESET HIGH out feature is enabled.
3.3.10.ALE/PROG:
Address Latch Enable (ALE) is an output pulse for latching the low byte of the address
during accesses to external memory. This pin is also the program pulse input (PROG) during
Flash programming.
3.3.11. PSEN:
Program Store Enable (PSEN) is the read strobe to external program memory. When the
AT89S52 is executing code from external program memory, PSEN is activated twice each
machine cycle, except that two PSEN activations are skipped during each access to external data
memory.
3.3.12. EA/VPP:
External Access Enable EA must be strapped to GND in order to enable the device to
fetch code from external program memory locations starting at 0000H up to FFFFH.

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3.3.13. XTAL1:
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
3.3.14. XTAL2:
Output from the inverting oscillator amplifier.
Fig.5: Oscillator connections
Fig.6: External clock drive configuration
XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be
configured for use as an on-chip oscillator. Either a quartz crystal or ceramic resonator may be
used. To drive the device from an external clock source, XTAL2 should be left unconnected
while XTAL1 is driven.
3.3.15. Special Function Registers:
A map of the on-chip memory area called the Special Function Register (SFR). It should
be noted that not all of the addresses are occupied and unoccupied addresses may not be

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implemented on the chip. User software should not write 1s to these unlisted locations, since
they may be used in future products to invoke new features.
3.3.16. Timer 2 Registers:
Control and status bits are contained in registers T2CON and T2MOD for Timer 2. The
register pair (RCAP2H, RCAP2L) is the Capture/Reload register for Timer 2 in 16-bit capture
mode or 16-bit auto-reload mode.
3.3.17. Interrupt Registers:
The individual interrupt enable bits are in the IE register. Two priorities can be set for each of the
six interrupt sources in the IP register.
3.3.18. Dual Data Pointer Registers:
To facilitate accessing both internal and external data memory, two banks of 16-bit Data
Pointer Registers are provided: DP0 at SFR address locations 82H-83H and DP1 at 84H and
85H. Bit DPS = 0 in SFR AUXR1 selects DP0 and DPS = 1 selects DP1. The user should
ALWAYS initialize the DPS bit to the appropriate value before accessing the respective Data
Pointer Register.
3.3.19. Power off Flag:
The Power off Flag (POF) is located at bit 4 (PCON.4) in the PCON SFR. POF is set to
“1” during power up. It can be set and rest under software control and is not affected by reset.
3.3.20. Memory Organization:
MCS-51 devices have a separate address space for Program and Data Memory. Up to
64K bytes each of external Program and Data Memory can be addressed.
3.3.21. Program Memory:
If the EA pin is connected to GND, all program fetches are directed to external memory.
On the AT89S52, if EA is connected to VCC, program fetches to addresses 0000H through
1FFFH are directed to internal memory and fetches to addresses 2000H through FFFFH are to
external memory.

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3.3.22. Data Memory:
The AT89S52 implements 256 bytes of on-chip RAM. The upper 128 bytes occupy a
parallel address space to the Special Function Registers. This means that the upper 128 bytes
have the same addresses as the SFR space but are physically separate from SFR space.
3.3.23. Watchdog Timer (One-time Enabled with Reset-out):
The WDT is intended as a recovery method in situations where the CPU may be
subjected to software upsets. The WDT consists of a 14-bit counter and the Watchdog Timer
Reset (WDTRST) SFR. The WDT is defaulted to disable from exiting reset. To enable the WDT,
a user must write 01EH and 0E1H in sequence to the WDTRST register (SFR location 0A6H).
When the WDT is enabled, it will increment every machine cycle while the oscillator is
running.).
3.3.24. Timer 0:
Timer 0 functions as either a timer or event counter in four modes of operation. Timer 0
is controlled by the four lower bits of the TMOD register and bits 0, 1, 4 and 5 of the TCON
register. TMOD register selects the method of timer gating (GATE0), timer or counter operation
(T/C0#) and mode of operation (M10 and M00).
3.3.25. Mode 0 (13-bit Timer):
Mode 0 configures timer 0 as a 13-bit timer which is set up as an 8-bit timer (TH0
register) with a modulo-32 prescaler implemented with the lower five bits of the TL0 register.
The upper three bits of TL0 register are indeterminate and should be ignored. Prescaler overflow
increments the TH0 register.
3.3.26. Baud Rate Generator:
Timer 2 is selected as the baud rate generator by setting TCLK and/or RCLK in T2CON.
Note that the baud rates for transmit and receive can be different if Timer 2 is used for the
receiver or transmitter and Timer 1 is used for the other function. Setting RCLK and/or TCLK
puts Timer 2 into its baud rate generator mode.
3.3.27. Interrupts:

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The AT89S52 has a total of six interrupt vectors: two external interrupts (INT0 and
INT1), three timers interrupts (Timers 0, 1, and 2) and the serial port interrupt.
3.4 Bluetooth Module
Bluetooth is a wireless technology standard for exchanging data over short distances (using
short-wavelength radio transmissions in the ISM band from 2400–2480 MHz) from fixed and
mobile devices, creating personal area networks (PANs) with high levels of security. Created by
telecom vendor Ericsson in 1994, it was originally conceived as a wireless alternative to RS-232
data cables. It can connect several devices, overcoming problems of synchronization.
This module enables you to wireless transmit & receive serial data. It is a drop in
replacement for wired serial connections allowing transparent two way data communication. You
can simply use it for serial port replacement to establish connection between MCU or embedded
project and PC for data transfer. We have another model 3685 available without backing pcb
which operates on 3V only. This board operates on 5V and has LED indication and 3V regulator
onboard.
Communication and connection:
A master Bluetooth device can communicate with a maximum of seven devices in a piconet (an
ad-hoc computer network using Bluetooth technology), though not all devices reach this
maximum. The devices can switch roles, by agreement, and the slave can become the master (for
example, a headset initiating a connection to a phone will necessarily begin as master, as initiator
of the connection; but may subsequently prefer to be slave).
The Bluetooth Core Specification provides for the connection of two or more piconets to form a
scatter net, in which certain devices simultaneously play the master role in one piconet and the
slave role in another.
At any given time, data can be transferred between the master and one other device (except for
the little-used broadcast mode. The master chooses which slave device to address typically, it

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switches rapidly from one device to another in a round-robin fashion. Since it is the master that
chooses which slave to address, whereas a slave is (in theory) supposed to listen in each receive
slot, being a master is a lighter burden than being a slave. Being a master of seven slaves is
possible being a slave of more than one master is difficult. The specification is vague as to
required behavior in scatter nets.
Many USB Bluetooth adapters or "dongles" are available, some of which also include an IrDA
adapter. Older (pre-2003) Bluetooth dongles, however, have limited capabilities, offering only
the Bluetooth Enumerator and a less-powerful Bluetooth Radio incarnation. Such devices can
link computers with Bluetooth with a distance of 100 meters, but they do not offer as many
services as modern adapters do.
Uses:
Bluetooth is a standard wire-replacement communications protocol primarily designed for low
power consumption, with a short range (power-class-dependent, but effective ranges vary in
practice; see table below) based on low-cost transceiver microchips in each device. Because the
devices use a radio (broadcast) communications system, they do not have to be in visual line of
sight of each other, however a quasi optical wireless path must be viable.
The effective range varies due to propagation conditions, material coverage, production sample
variations, antenna configurations and battery conditions. In most cases the effective range of
Class 2 devices is extended if they connect to a Class 1 transceiver, compared to a pure Class 2
network. This is accomplished by the higher sensitivity and transmission power of Class 1
devices
Bluetooth vs. Wi-Fi:
Bluetooth and Wi-Fi (the brand name for products using IEEE 802.11 standards) have some
similar applications setting up networks, printing, or transferring files. Wi-Fi is intended as a
replacement for cabling for general local area network access in work areas. This category of
applications is sometimes called wireless local area networks (WLAN). Bluetooth was intended
for portable equipment and its applications. The category of applications is outlined as the

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wireless personal area network (WPAN). Bluetooth is a replacement for cabling in a variety of
personally carried applications in any setting and also works for fixed location applications such
as smart energy functionality in the home (thermostats, etc.).
Wi-Fi is a wireless version of a common wired Ethernet network, and requires configuration to
set up shared resources, transmit files, and to set up audio links (for example, headsets and
hands-free devices). Wi-Fi uses the same radio frequencies as Bluetooth, but with higher power,
resulting in higher bit rates and better range from the base station. The nearest equivalents in
Bluetooth are the DUN profile, which allows devices to act as modem interfaces, and the PAN
profile, which allows for ad-hoc networking.
Device:
Bluetooth exists in many products, such as telephones, tablets, media players, Lego Mind storms
NXT, PlayStation 3, PS Vita, the Nintendo Wii, and some high definition headsets, modems, and
watches. The technology is useful when transferring information between two or more devices
that are near each other in low-bandwidth situations. Bluetooth is commonly used to transfer
sound data with telephones (i.e., with a Bluetooth headset) or byte data with hand-held
computers (transferring files).
Bluetooth protocols simplify the discovery and setup of services between devices. Bluetooth
devices can advertise all of the services they provide. This makes using services easier because
more of the security, network address and permission configuration can be automated than with
many other network types.
Features:
1. 5V power operation
2. UART interface

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3. 10 meters range
4. Easy to use
5. Minimum External Components
6. Status LED
Applications:
1. Wireless Telemetry
2. Remote Data Logging
3. Robotics
4. Sensor Monitoring
5. Remote Programming
Product Specifications:
Bluetooth protocol v2.0
1. Range 10 meters
2. Frequency: 2.4 GHz ISM
3. Modulation: GFSK
4. Transmit power: 4dBm
5. Sensitivity: 84dBm
6. Rate: 2.1Mbps (Max) /160kbps (Async); 1Mbps(Sync)
7. Authentication & Encryption
8. Power Supply: +5 VDC 50mA
9. Operating Temperate: -20C to +55 C
10. Dimensions: 26.9 mm x 13 mm x 2.2 mm

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PC Data Transfer Mode:
We supply module with 9600 baud rate in ready to use with PC. You will need a USB Bluetooth
Adapter at PC side or Bluetooth Enabled Laptop to connect to our Bluetooth module.
Module supplied by us with this setting: 9600 baud rate, Pair Code: 1234
Note: There are many low cost USB Bluetooth dongle adapters for PC available with mobile
spares suppliers. You can use any of them with PC to establish Bluetooth connection.
3.5 TRIAC BT136:
General Description

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Glass passivated, sensitive gate triacs in a plastic envelope, intended for use in general purpose
bidirectional switching and phase control applications, where high voltages sensitivity is required
in all four quadrants.

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3.9 TRIAC DRIVER MOC3021:
The MOC301XM and MOC302XM series are optically isolated triac driver devices. These
devices consist of gallium arsenide infrared emitting diodes, optically coupled to silicon bilateral
switch and are designed for applications requiring isolated triac triggering, low–current isolated
ac switching, high electrical isolation (to 7500 VAC peak), high detector standoff voltage, small
size, and low cost. This series is designed for interfacing between electronic controls and power
triacs to control resistive and inductive loads for 115/240V AC operations.
Features:
 Low input current required (typically 5mA).
 High isolation voltage-minimum 7500 VAC peak
Applications:
 TRIAC driver

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 Industrial controls
 Traffic lights
 Vending machines
 Motor control
 Solid state relay
 Solenoid/valve controls
 Static AC power switch
 Incandescent lamp dimmers
 Lamp ballasts
3.6. Liquid Crystal Display:
LCD stands for Liquid Crystal Display. LCD is finding wide spread use replacing LEDs (seven
segment LEDs or other multi segment LEDs) because of the following reasons
 The declining prices of LCDs.
 The ability to display numbers, characters and graphics. This is in contrast to LEDs,
which are limited to numbers and a few characters.
 Incorporation of a refreshing controller into the LCD, thereby relieving the CPU of the
task of refreshing the LCD. In contrast, the LED must be refreshed by the CPU to keep
displaying the data.
Fig.7: Front part of LCD

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3.6.1. Pins Functions:
There are pins along one side of the small printed board used for connection to the
microcontroller. There are total of 14 pins marked with numbers (16 in case the background light
is built in). Their function is described in the table:
Table3:Pin functioning of LCD

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Function Pin Number Name Logic State Description
Ground 1 Vss - 0V
Power supply 2 Vdd - +5V
Contrast 3 Vee - 0 – Vdd
0 D0 – D7 are interpreted as commands
1 D0 – D7 are interpreted as data
0 D0 – D7 are interpreted as commands
1 D0 – D7 are interpreted as data
0 Write data (fromcontroller to LCD)
1 Read data (fromLCD to controller)
0 Access to LCD disabled
1 Normaloperating
From1 to 0 Data/commands are transferred to LCD
7 D0 0/1 Bit 0 LSB
8 D1 0/1 Bit 1
9 D2 0/1 Bit 2
10 D3 0/1 Bit 3
11 D4 0/1 Bit 4
12 D5 0/1 Bit 5
13 D6 0/1 Bit 6
14 D7 0/1 Bit 7 MSB
Data /
commands
Controlof
operating 4 RS
Controlof
operating
4 RS
5 R/W
6 E

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3.6.2.LCD screen:
LCD screen consists of two lines with 16 characters each. Each character consists of 5x7
dot matrix.
Fig.8: LCD screen
3.6.3.LCD Basic Commands:
The below basic commands clearly declare their functioning:
I/D 1 = Increment (by 1) R/L 1 = Shift right
0 = Decrement (by 1) 0 = Shift left
S 1 = Display shift on DL 1 = 8-bit interface
0 = Display shift off 0 = 4-bit interface
D 1 = Display on N 1 = Display in two lines
0 = Display off 0 = Display in one line
U 1 = Cursor on F 1 = Character format 5x10 dots
0 = Cursor off 0 = Character format 5x7 dots
B 1 = Cursor blink on D/C 1 = Display shift
0 = Cursor blink off 0 = Cursor shift

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3.6.4. LCD Connection:
Depending on how many lines are used for connection to the microcontroller, there are 8-
bit and 4-bit LCD modes. The appropriate mode is determined at the beginning of the process in
a phase called “initialization”. In the first case, the data are transferred through outputs D0-D7 as
it has been already explained. In case of 4-bit LED mode, for the sake of saving valuable I/O
pins of the microcontroller, there are only 4 higher bits (D4-D7) used for communication, while
other may be left unconnected.
Consequently, each data is sent to LCD in two steps: four higher bits are sent first (that
normally would be sent through lines D4-D7), four lower bits are sent afterwards. With the help
of initialization, LCD will correctly connect and interpret each data received. Besides, with
regards to the fact that data are rarely read from LCD (data mainly are transferred from
microcontroller to LCD) one more I/O pin may be saved by simple connecting R/W pin to the
Ground. Such saving has its price.
3.6.5.LCD Initialization:
Once the power supply is turned on, LCD is automatically cleared. This process lasts for
approximately 15mS. After that, display is ready to operate. The mode of operating is set by
default. This means that:
1. Display is cleared
2. Mode
DL = 1 Communication through 8-bit interface
N = 0 Messages are displayed in one line
F = 0 Character font 5 x 8 dots
3. Display/Cursor on/off
D = 0 Display off
U = 0 Cursor off
B = 0 Cursor blink off
4. Character entry
ID = 1 Addresses on display are automatically incremented by 1
S = 0 Display shift off

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Fig.9: Procedure on 8 bit initialization
3.6.6. Contrast control:
To have a clear view of the characters on the LCD, contrast should be adjusted. To adjust
the contrast, the voltage should be varied. For this, a preset is used which can behave like a
variable voltage device
Fig.10:Reset

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3.6.7.Potentiometer:
Variable resistors used as potentiometers have all three terminals connected. This
arrangement is normally used to vary voltage.
Fig.11: Potentiometer symbol
3.6.8.Presets:
These are miniature versions of the standard variable resistor. They are designed to be
mounted directly onto the circuit board and adjusted only when the circuit is built.
Fig.12: LCD interface with the microcontroller (4-bit mode)

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CHAPTER: 4
FIRMWARE IMPLEMENTATION OF THE PROJECT DESIGN
This chapter briefly explains about the firmware implementation of the project.
4.1. Software Tools Required:
Keil µv3, Proload are the two software tools used to program microcontroller. The
working of each software tool is explained below in detail.
4.1.1. Programming Microcontroller:
A compiler for a high level language helps to reduce production time. To program the
AT89S52 microcontroller the Keil µv3 is used
4.1.2. Keil Compiler:
Keil compiler is software used where the machine language code is written and compiled.
After compilation, the machine source code is converted into hex code which is to be dumped
into the microcontroller for further processing. Keil compiler also supports C language code.
Fig.15: Compilation of source code

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Fig.16: Run the compiled program
4.1.3. Proload:
Proload is software which accepts only hex files. Once the machine code is converted
into hex code, that hex code has to be dumped into the microcontroller and this is done by the
Proload. The board itself but in order to switch on that power supply, a source is required.
Fig.17: Atmel 8051 Device Programmer

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4.1.4. Features:
 Supports major Atmel 89 series devices
 Auto Identify connected hardware and devices
 Error checking and verification in-built
 Lock of programs in chip supported to prevent program copying
 20 and 40 pin ZIF socket on-board
4.1.5. Description:
It is simple to use and low cost, yet powerful flash microcontroller programmer for the Atmel 89
series. It will Program, Read and Verify Code Data, Write Lock Bits, Erase and Blank Check.
All fuse and lock bits are programmable. This programmer has intelligent onboard firmware and
connects to the serial port. All devices also have a number of lock bits to provide various levels
of software and programming protection. These lock bits are fully programmable using this
programmer. Lock bits are useful to protect the program to be read back from microcontroller
only allowing erase to reprogram the microcontroller. The programmer connects to a host
computer using a standard RS232 serial port. All the programming 'intelligence' is built into the
programmer so you do not need any special hardware to run it. Programmer comes with window
based software for easy programming of the devices.

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Fig.18:Preload the cycle to load the program
CHAPTER 5
CIRCUIT DIAGRAM
5.1. SCHEMATIC DIAGRAM:

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5.2. WORKING PROCEDURE:

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The main aim of the project is to control the loads from the android phone using
through Bluetooth communication link. Android is a Linux based operating system designed
primarily for mobile devices and it is a open source.
To operate this project, first of all we should download an application from
google play store called “Bluetooth Spp”. After that switch on the Bluetooth in the android
mobile and the Bluetooth module in hardware kit. Then pair each other and send the commands
from the android mobile by sending the voice commands from the android mobile, the data was
transmitted through Bluetooth and received by the Bluetooth module at kit and further it sends
this command to 8051. According to the command received by itself, the microprocessor
controls the particular load by using TRIAC circuitry.
The code was written in C language using KIEL compiler and the relevant hex
file was dumped into the microcontroller using proload software.
CHAPTER 6
RESULTS AND DISCUSSIONS

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6.1 Results
Assemble the circuit on the PCB as shown in above circuit diagram. After assembling the circuit
on the PCB, check it for proper connections before switching on the power supply.
With the help of this project we had implemented advanced low cost voice recognition based
smart home/office automation using android mobile. We controlled the ac loads by using voice
commands.
The communication is properly done without any interference between different modules in the
design. Design is done to meet all the specifications and requirements. Software tools like Keil
Uvision Simulator, Proload to dump the source code into the microcontroller, Orcad Lite for the
schematic diagram have been used to develop the software code before realizing the hardware.
Circuit is implemented in Orcad and implemented on the microcontroller board. The
performance has been verified both in software simulator and hardware design. The total circuit
is completely verified functionally and is following the application software.
It can be concluded that the design implemented in the present work provide portability,
flexibility and the data transmission is also done with low power consumption.
6.2 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
TRAIC.
6.3. Advantages
1. Easy to operate loads by voice commands

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2. Easy to install
3. It makes connecting to different devices convenient
4. It is wireless
5. It is free to use if the device is installed with it
5. It is cheap
6.4. Disadvantages
1. If installed on a cell phone it is prone to receiving cell phone viruses
2. It can only connect two devices at once
6.5. Applications:
1. Office automation
2. Home automation
3. Machines controlling system in industry
4. Door access control system
BIBLIOGRAPHY
The 8051 Micro controller and Embedded Systems - Muhammad Ali Mazidi

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Janice Gillispie Mazidi
The 8051 Micro controller Architecture, Programming & Applications - Kenneth J.Ayala
Fundamentals Of Micro processors and Micro computers - B.Ram
Micro processor Architecture, Programming & Applications - Ramesh S.Gaonkar
Electronic Components - D.V.Prasad
Wireless Communications- Theodore S. Rappaport
Mobile Tele Communications - William C.Y. Lee
Referencesonthe Web:
www.national.com
www.atmel.com
www.microsoftsearch.com
www.geocities.com