sms controlled home appliance
TRANSCRIPT
SMS CONTROLLED HOME APPLIANCE
ABSTRACT
Mobile plays a vital role in day-to-day life. It is an easier way to establish
communication. A number of technologies works behind it, GSM is one of them. The
objective of this project is to control the Machineries in the industrial and appliances in home
through the GSM Technique.
In this project we interface Mobile and Microcontroller with the help of Data
Cable and RS232 level converter for example when you are away from home and want to
switch ‘on’ any Machine like Fan, Air cooler, by sending SMS that contains the
corresponding Machine number and type of mode such that ON (or) OFF the machine by the
Mobile Phone. This is interfaced with the Microcontroller in company or home.
After receiving the message, the Mobile sends the data signal to the Microcontroller
through the data cable and RS232 level logic converter. Level converter gives the signal in
the form of 0 and 5V pulse to the Microcontroller.
A relay is an electrically operated switch. Current flowing through the coil of the
relay creates a magnetic field which attracts a lever and changes the switch contacts. The coil
of a relay passes a relatively large current, typically 30mA for a 12V relay, but it can be as
much as 100mA for relays designed to operate from lower voltages
The Microcontroller is the embedded device which has on chip program memory
in which the machine control program is stored. Suppose if you send the SMS like Machine 1
ON, in company corresponding information is displayed in the LCD display through
Microcontroller.
Then the Microcontroller activates the relay which is connected to
corresponding Machine. Now the Machine 1 is switched ON by relay. Relay is activated
through Relay Driver Circuit which is controlled by Microcontroller. By using this project
we can control the industrial Machineries Automatically with help of GSM Technique.
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INDEX
S.No Pg.No
1. INTRODUCTION……………………………………...………………......…....…1
2. SYSTEM MODEL…………………………………………………….....…............2
2.1BASIC MODEL OF THE SYSTEM……………………………….……....…..2
2.1.1DESCRIPTION..........................................................................................3
2.2CIRCUIT DIAGRAM……………………………......………………...…....….4
3. HARWARE DESCRIPTION……………………………………......……….......…5
3.1MICROCONTROLLER (AT89S51)……………………….....……..……....…5
3.1.1CRITERIA FOR CHOOSING MICROCONTROLLER……...........….5
3.1.2DESCRIPTION………………………………….......……………....…...6
3.1.3FEATURES……………………………………………............................7
3.1.4PIN CONFIGURATION………………………..………….....….............8
3.1.5PIN DESCRIPTION…………………………………….......……......….9
3.1.6BLOCK DIAGRAM…………………………………….........….…..…10
3.2RELAY…………………………………………...………….....………...…....11
3.2.1CIRCUIT DESCRIPTION…………………………...……..…........…..13
3.3LIQUID CRYSTAL DISPLAY……………………......……....………....…...14
3.3.1PIN DESCRIPTION…………………………………...….....….………16
2
3.3.2LCD COMMAND DESCRIPTION……….......………………….……18
3.3.3CHECKING THE BUSY STATUS OF LCD……………….............….19
3.3.4INITIALIZING THE LCD………………………….......………..……..19
3.4 POWER SUPPLY………………………………....…………….……..……..20
3.4.1 TRANSFORMER………………....…………………………......….....20
3.4.2 BRIDGE RECTIFIER……………......…………………………...…....21
3.4.3 IC VOLTAGE REGULATOR……………………......…………...…...21
4.SOFTWARE……………………………………………………….….....…...……22
4.1INTRODUCTION TO KEIL………………………………………...........….22
4.2CONCEPT OF COMPILER…………….....……………………….........…...22
4.3CONCEPT OF CROSS COMPILER …………………………….…......…....23
4.4WHY DO WE NEED A CROSS COMPILER.................................................23
4.5KEIL C CROSS COMPILER………………….....……………………......…24
5. SOURCE CODE…………………………….....…………………………..….…..29
5.1FLOW CHART.................................................................................................32
6. ADVANTAGES, DISADVANTAGES AND APPLICATIONS……….......….....35
6.1ADVANTAGES……………………….....……………………………......….35
6.2DISADVANTAGES…………….....………………………………….....…...35
6.3APPLICATIONS…………………………………......……………….....……35
7. RESULT AND CONCLUSION……………......……………………………..…..36
7.1RESULT……………………………….....……………………………….......36
7.2CONCLUSION…………………………......…………………….…….....….36
8. REFERENCES……………………………......………………………………...…37
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LIST OF FIGURES
S.No Pg.No
1. BASIC MODEL OF THE SYSTEM………………………………...……………..2
2. CIRCUIT DIAGRAM……………………………………………………...………4
3. PIN DIAGRAM OF 8051………………………………………………...…...……8
4. BLOCK DIAGRAM OF 8051…………………………………..………………...10
5. RELCIRCUIT………………………………………...…………..……………….11
6. RELAY SWITCH………………………………..………………………………..12
7. LCD DISPLAY………………………...……………………………………….....15
8. BLOCK DIAGRAM OF POWER SUPPLY...........................................................20
9. BRIDGE RECTIFIER..............................................................................................21
10. CIRCUIT DIAGRAM OF POWER SUPPLY.......................................................21
11. KEIL WORK SPACE............................................................................................27
12. CONVERSION TO HEXA DECIMAL FILE.......................................................28
LIST OF TABLES
S.No Pg.No
1. PIN DESCRIPTION................................................................................................16
2. LCD COMMANDS.................................................................................................18
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1. INTRODUCTION
The embedded system is a combination of computer hardware, software and
perhaps additional mechanical or other parts, designed to perform a specific function within
a given time frame. The embedded software is required for all real-time applications and is
developed using a real time operating system (RTOS), as it helps to schedule and execute
tasks based on priority in a predictable manner.
Industry analysts estimate that over 54 percent of future software
development will be in the embedded technology space. According to an IDC report the
international market as a whole expects product development worth $75 billion, which will
require as many as 150,000 trained professionals in embedded systems development by the
year 2005.
This project is based on the embedded systems technology using
microcontroller. The objective of this project is to control the Machineries in the industrial
and appliances in home through the GSM Technique. In this project we interface Mobile and
Microcontroller with the help of Data Cable and RS232 level converter for an example when
you are away from your home and you wants to switch ‘on’ the any one Machine like Fan,
Air cooler, you have to send SMS that contains the corresponding Machine number and type
of mode such that ON (or) OFF to the Mobile Phone. This is interface with the
Microcontroller in company or home.
The Microcontroller is the embedded device which has on chip program memory
in which the machine control program is stored. Suppose if you send the SMS like Machine 1
ON, in company corresponding information is displayed in the LCD display through
Microcontroller.
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2. SYSTEM MODEL
2.1BASIC MODEL OF THE SYSTEM:
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BASIC MODEL OF THE SYSTEM
3. HARDWARE DESCRIPTION
3.1MICRO CONTROLLER (AT89S51):
7
3.1.1 CRITERIA FOR CHOOSING A MICROCONTROLLER
The basic criteria for choosing a microcontroller suitable for the application are:
1) The first and foremost criterion is that it must meet the task at hand efficiently and
cost effectively. In analyzing the needs of a microcontroller-based project, it is seen whether
an 8- bit, 16-bit or 32-bit microcontroller can best handle the computing needs of the task
most effectively. Among the other considerations in this category are:
i. Speed: The highest speed that the microcontroller supports.
ii. Packaging: It may be a 40-pin DIP (dual inline package) or a QFP (quad flat package), or
some other packaging format. This is important in terms of space, assembling, and
prototyping the end product.
iii. Power consumption: This is especially critical for battery-powered products.
iv. The number of I/O pins and the timer on the chip.
v. How easy it is to upgrade to higher –performance or lower consumption versions.
vi. Cost per unit: This is important in terms of the final cost of the product in which a
microcontroller is used.
2) The second criterion in choosing a microcontroller is how easy it is to develop
products around it. Key considerations include the availability of an assembler, debugger,
compiler, technical support.
3) The third criterion in choosing a microcontroller is its ready availability in needed
quantities both now and in the future. Currently of the leading 8-bit microcontrollers, the
8051 family has the largest number of diversified suppliers. By supplier is meant a producer
besides the originator of the microcontroller. By supplier is meant a producer besides the
originator of the microcontroller. In the case of the 8051, this has originated by Intel several
companies also currently producing the 8051. Thus the microcontroller AT89S52, satisfying
the criterion necessary for the proposed application is chosen for the task.
3.1.2 DESCRIPTION:
The 8052 family of microcontrollers is based on an architecture which is
highly optimized for embedded control systems. It is used in a wide variety of applications
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from military equipment to automobiles to the keyboard. Second only to the Motorola,
68HC11 in eight bit processors sales, the 8052 family of microcontrollers is available in a
wide array of variations from manufacturers such as Intel, Philips, and Siemens. These
manufacturers have added numerous features and peripherals to the 8052 such as I2C
interfaces, analog to digital converters, watchdog timers, and pulse width modulated outputs.
Variations of the 8052 with clock speeds up to 40MHz and voltage requirements
down to 1.5 volts are available. This wide range of parts based on one core makes the 8052
family an excellent choice as the base architecture for a company's entire line of products
since it can perform many functions and developers will only have to learn this one platform.
The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller
with 8K bytes of in-system programmable Flash memory. The device is manufactured using
Atmel’s high-density nonvolatile memory technology and is compatible with the industry-
standard 80C52 instruction set and pin out.
The on-chip Flash allows the program memory to be reprogrammed in-system
or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU
with in-system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful
microcontroller 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
con-tents but freezes the oscillator, disabling all other chip functions until the next interrupt
or hardware reset.
3.1.3 FEATURES:
• Compatible with MCS-52 Products
• 8K Bytes of In-System Programmable (ISP) Flash Memory
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• 4.0V to 5.5V Operating Range
• Fully Static Operation: 0 Hz to 33 MHz
• 256 x 8-bit Internal RAM
• 32 Programmable I/O Lines
• Two 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
• Fast Programming Time
3.1.4 PIN CONFIGURATION:
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PIN DIAGRAM OF 8051
3.1.5 PIN DESCRIPTION:
VCC: Supply voltage.
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GND: Ground.
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.
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. In
addition, P1.0 and P1.1 can be configured to be the timer/counter2 external count input
(P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively.
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, Port2 pins that are
externally being pulled low will source current (IIL) because of the internal pull-ups
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. When 1s are written to Port 3 pins, they are pulled
high by the internal pull-ups and can be used as inputs. As inputs, Port3 pins that are
externally being pulled low will source current (IIL) because of the pull ups. Port 3 receives
some control signals for Flash programming and verification.
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.
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3.1.6 BLOCK DIAGRAM:
BLOCK DIAGRAM OF THE 8051
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3.2RELAY:
RELAY CIRCUIT
A relay is an electrically operated switch. Current flowing through the coil of
the relay creates a magnetic field which attracts a lever and changes the switch contacts. The
coil current can be on or off so relays have two switch positions and they are double throw
(changeover) switches. Relays allow one circuit to switch a second circuit which can be
completely separate from the first. For example a low voltage battery circuit can use a relay
to switch a 230V AC mains circuit. There is no electrical connection inside the relay between
the two circuits; the link is magnetic and mechanical.
The coil of a relay passes a relatively large current, typically 30mA for a 12V
relay, but it can be as much as 100mA for relays designed to operate from lower voltages.
Most ICs (chips) cannot provide this current and a transistor is usually used to amplify the
small IC current to the larger value required for the relay coil. The maximum output current
for the popular 555 timer IC is 200mA so these devices can supply relay coils directly
without amplification.
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Relays are usually SPDT or DPDT but they can have many more sets of switch
contacts, for example relays with 4 sets of changeover contacts are readily available. Most
relays are designed for PCB mounting but you can solder wires directly to the pins providing
you take care to avoid melting the plastic case of the relay. The animated picture shows a
working relay with its coil and switch contacts. You can see a lever on the left being attracted
by magnetism when the coil is switched on. This lever moves the switch contacts. There is
one set of contacts (SPDT) in the foreground and another behind them, making the relay
DPDT. You can see a lever on the left being attracted by magnetism when the coil is
switched on. This lever moves the switch contacts.
RELAY SWITCH
The relay's switch connections are usually labeled COM, NC and NO:
COM = Common, always connect to this, it is the moving part of the switch.
NC = Normally Closed, COM is connected to this when the relay coil is off.
NO = Normally Open, COM is connected to this when the relay coil is on.
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3.2.1 CIRCUIT DESCRIPTION:
This circuit is designed to control the load. The load may be motor or any other
load. The load is turned ON and OFF through relay. The relay ON and OFF is controlled by
the pair of switching transistors (BC 547). The relay is connected in the Q2 transistor
collector terminal. A Relay is nothing but electromagnetic switching device which consists of
three pins. They are Common, Normally close (NC) and Normally open (NO).
The relay common pin is connected to supply voltage. The normally open (NO)
pin connected to load. When high pulse signal is given to base of the Q1 transistors, the
transistor is conducting and shorts the collector and emitter terminal and zero signals is given
to base of the Q2 transistor. So the relay is turned OFF state.
When low pulse is given to base of transistor Q1 transistor, the transistor is
turned OFF. Now 12v is given to base of Q2 transistor so the transistor is conducting and
relay is turned ON. Hence the common terminal and NO terminal of relay are shorted. Now
load gets the supply voltage through relay.
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3.3 LIQUID CRYSTAL DISPLAY
The LCD is used for the purpose of displaying the words which we give in the
program code. This code will be executed on microcontroller chip. By following the
instructions in code the LCD display the related words.
Liquid crystal displays (LCDs) have materials which combine the properties of
both liquids and crystals. Rather than having a melting point, they have a temperature range
within which the molecules are almost as mobile as they would be in a liquid, but are
grouped together in an ordered form similar to a crystal.
An LCD consists of two glass panels, with the liquid crystal material sand witched
in between them. The inner surface of the glass plates are coated with transparent electrodes
which define the character, symbols or patterns to be displayed polymeric layers are present
in between the electrodes and the liquid crystal, which makes the liquid crystal molecules to
maintain a defined orientation angle.
One each polarisers are pasted outside the two glass panels. These polarisers
would rotate the light rays passing through them to a definite angle, in a particular direction.
When the LCD is in the off state, light rays are rotated by the two polarisers and
the liquid crystal, such that the light rays come out of the LCD without any orientation, and
hence the LCD appears transparent.
When sufficient voltage is applied to the electrodes, the liquid crystal molecules
would be aligned in a specific direction. The light rays passing through the LCD would be
rotated by the polarisers, which would result in activating /highlighting the desired
characters.
The LCD’s are lightweight with only a few millimeters thickness. Since the LCD’s
consume less power, they are compatible with low power electronic c rcuits, and can be
powered for long durations.
The LCD don’t generate light and so light is needed to read the display. By using
backlighting, reading is possible in the dark. The LCD’s have long life and a wide operating
temperature range.
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The LCDs used exclusively in watches, calculators and measuring instruments
are the simple seven-segment displays, having a limited amount of numeric data. The recent
advances in technology have resulted in better legibility, more information displaying
capability and a wider temperature range. These have resulted in the LCDs being extensively
used in telecommunications and entertainment electronics. The LCDs have even started
replacing the cathode ray tubes (CRTs) used for the display of text and graphics, and also in
small TV applications. . Fig below shows the LCD display.
LCD DISPLAY
The LCD display consists of two lines, 20 characters per line that is interfaced
with the PIC16F73.The protocol (handshaking) for the display is as shown in Fig. The
display contains two internal byte-wide registers, one for commands (RS=0) and the second
for characters to be displayed (RS=1). It also contains a user-programmed RAM area (the
character RAM) that can be programmed to generate any desired character that can be
formed using a dot matrix. To distinguish between these two data areas, the hex command
byte 80 will be used to signify that the display RAM address 00h will be chosen Port1 is used
to furnish the command or data type, and ports 3.2 to 3.4 furnish register select and
read/write levels.
A liquid crystal is a material (normally organic for LCDs) that will flow like a
liquid but whose molecular structure has some properties normally associated with solids.
The Liquid Crystal Display (LCD) is a low power device. The power requirement is typically
in the order of microwatts for the LCD. However, an LCD requires an external or internal
light source. It is limited to a temperature range of about 0°C to 60°C and lifetime is an area
of concern, because LCDs can chemically degrade.
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There are two major types of LCDs which are:
Dynamic-scattering LCDs and
Field-effect LCDs
The turn-on and turn-off time is an important consideration in all displays. The
response time of LCDs is in the range of 100 to 300ms.The lifetime of LCDs is steadily
increasing beyond 10,000+hours limit. Since the color generated by LCD units is dependent
on the source of illumination, there is a wide range of color choice. The lifetime of LCDs is
steadily increasing . Since the color generated by LCD units is dependent on the source of
illumination, there is a wide range of color choice.
3.3.1PIN DESCRIPTION
Pins Description
1 "Vss" - Ground
2 "Vcc" - +5v power supply
3 "Vee" - Contrast Voltage
4 "R/S" - Instruction/Register Select
5 "R/W" - Read/Write LCD Registers
6 "E" - Enable
7 - 14 Data I/O Pins
TABLE: PIN DESCRIPTION
Vcc, Vss, VEE
While Vcc and Vss provide +5v and ground, respectively, Vee is used for controlling
LCD contrast.
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RS, Register Select
There are two very important registers inside the LCD. The RS pin is used for their
selection as follows.
If RS = 0, the instruction command code register is selected, allowing the user to send
as command code register is selected, allowing the user to send a command such as clear
display, cursor at home, etc.
If RS = 1 the data register is selected, allowing the user to send data to be displayed
on the LCD.
R/W, Read/Write
R/W input allows the user to write information to the LCD or read information from
it.
R/W = 1 when reading;
R/W = 0 when writing.
E, Enable
The enable pin is used by the LCD to latch information presented to its data pins.
When data is supplied to data pins, a high - to - low pulse must be applied to this pin in order
for the LCD latch in the data pins. This pulse must be a minimum of 450 ns wide.
D0 - D7
The 8 - bit data pins, D0 - D7, are used to send information to the LCD or read the
contents of the LCD's internal registers.To display letters and numbers, send ASCII codes for
the letters A - Z, a - z, and numbers 0 - 9 to these pins while RS = 1. When RS = 0 to check
the busy flag bit to see if the LCD is ready to receive information. The busy flag is D7 and
can be read when R/W = 1 and RS = 0, as follows: if R/W = 1, RS = 0. When D7 =1 (busy
flag = 1), the LCD is busy taking care of internal operation and will not accept any new
information. The description of the pins is shown in Table below.
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3.3.2 LCD Commands
RS R/W D7 D6 D5 D4 D3 D2 D1 D0 Function
0 0 0 0 0 0 0 0 0 1 Clear LCD &memory,
Home cursor
0 0 0 0 0 0 0 0 1 0 Clear and home cursor
only
0 0 0 0 0 0 0 1 1/0 S Screen action as
display character
Written S=1/0:shift
screen/ cursor
0 0 0 0 0 0 1 D C B D=1/0: Screen on/off
C=1/0: Cursor on/off
B=1/0: Cursor blink/no
blinks
0 0 0 0 0 1 S/C R/L 0 0 S/C=1/0: Screen/Cursor
R/L==1/0: Shift one
space R/L
0 0 0 0 1 DL N F 0 0 DL=1/0: 8/4 bits per
character N=1/0: 2/1
Rows of characters
F=1/0:
5*10/5*7dots/character
0 0 0 1 Character address Write to character
RAM address after this
0 0 1 Display data address Write to display RAM
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address after this
0 1 BF Current addresses BF=1/0:busy/Not busy
3.3.3 CHECKING THE BUSY STATUS OF THE LCD
As previously mentioned, it takes a certain amount of time for each instruction to
be executed by the LCD. The delay varies depending on the frequency of the crystal attached
to the oscillator input of the controller as well as the instruction which is being executed.
While it is possible to write code that waits for a specific amount of time to allow the LCD to
execute instructions, this method of "waiting" is not very flexible.
3.3.4 INITIALIZING THE LCD
LCD must be initialized and configured before using. This is accomplished by
sending a number of initialization instructions to the LCD.
The first instruction send must tell the LCD whether it is to be communicated
with an 8-bit or 4-bit data bus. 5x8 dot character font should also be selected. These two
options are selected by sending the command 38h to the LCD as a command.
a) Clearing the Display
When the LCD is first initialized, the screen should automatically be cleared by the
controller.
b) Writing Text into the LCD
The data to be displayed is send to the LCD through data bus.
c) Cursor Positioning
The cursor positioning in a LCD can be done in the right entry mode or left entry mode. As
left entry mode is flexible it is implemented.
.
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3.4 POWER SUPPLY:
The power supply circuits built using filters, rectifiers, and then voltage
regulators. Starting with an ac voltage, a steady dc voltage is obtained by rectifying the ac
voltage, then filtering to a dc level, and finally, regulating to obtain a desired fixed dc
voltage. The regulation is usually obtained from an IC voltage regulator unit, which takes a
dc voltage and provides a somewhat lower dc voltage, which remains the same even if the
input dc voltage varies, or the output load connected to the dc voltage changes. The block
diagram of power supply is shown in fig below.
AC Transformer Rectifier Filter Regulator Load
BLOCK DIAGRAM OF POWER SUPPLY
3.4. TRANSFORMER
The potential transformer will step down the power supply voltage (0-230V) to (0-
6V) level. Then the secondary of the potential transformer will be connected to the precision
rectifier, which is constructed with the help of op–amp. The advantages of using precision
rectifier are it will give peak voltage output as DC, rest of the circuits will give only RMS
output.
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3.4.2BRIDGE RECTIFIER
Bridge rectifier is used to maintain the proper DC polarity at the input to the
circuit. It comprises of four diodes connected to form a bridge. It uses the entire AC wave
(both positive and negative sections). 1.4V is used up in the bridge rectifier because each
diode uses 0.7V when conducting and there are always two diodes conducting, as shown in
fig
AC I/P
BRIDGE RECTIFIER
3.4.3 IC VOLTAGE REGULATORS:
The series 78 regulators provide fixed regulated voltages from 5 to 24 V.
Unregulated input voltage Vin is filtered by capacitor C1 and connected to the IC’s IN
terminal. The IC’s OUT terminal provides a regulated + 12V which is filtered by capacitor
C2. The third IC terminal is connected to ground (GND).
CIRCUIT DIAGRAM OF POWER SUPPLY
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4. SOFTWARE
4.1INTRODUCTION TO KEIL:
Keil is a cross compiler. So first we have to understand the concept of compilers
and cross compilers. After then we shall learn how to work with keil.
4.2CONCEPT OF COMPILER: -
Compilers are programs used to convert a High Level Language to object code.
Desktop compilers produce an output object code for the underlying microprocessor, but not
for other microprocessors. I.E the programs written in one of the HLL like ‘C’ will compile
the code to run on the system for a particular processor like x86 (underlying microprocessor
in the computer). For example compilers for Dos platform is different from the Compilers for
Unix platform.
So if one wants to define a compiler then compiler is a program that translates
source code into object code. The compiler derives its name from the way it works, looking
at the entire piece of source code and collecting and reorganizing the instruction. See there is
a bit little difference between compiler and an interpreter. Interpreter just interprets whole
program at a time while compiler analyzes and execute each line of source code in
succession, without looking at the entire program.
The advantage of interpreters is that they can execute a program immediately.
Secondly programs produced by compilers run much faster than the same programs executed
by an interpreter. However compilers require some time before an executable program
emerges. Now as compilers translate source code into object code, which is unique for each
type of computer, many compilers are available for the same language.
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4.3CONCEPT OF CROSS COMPILER: -
A cross compiler is similar to the compilers but we write a program for
the target processor (like 8051 and its derivatives) on the host processors (like computer of
x86)
It means being in one environment you are writing a code for another
environment is called cross development. And the compiler used for cross development is
called cross compile
So the definition of cross compiler is a compiler that runs on one
computer but produces object code for a different type of computer. Cross compilers are used
to generate software that can run on computers with a new architecture or on special-purpose
devices that cannot host their own compilers. Cross compilers are very popular for embedded
development, where the target probably couldn't run a compiler. Typically an embedded
platform has restricted RAM, no hard disk, and limited I/O capability. Code can be edited
and compiled on a fast host machine (such as a PC or Unix workstation) and the resulting
executable code can then be downloaded to the target to be tested. Cross compilers are
beneficial whenever the host machine has more resources (memory, disk, I/O etc) than the
target. Keil C Compiler is one such compiler that supports a huge number of host and target
combinations. It supports as a target to 8 bit microcontrollers like Atmel and Motorola etc.
4.4WHY DO WE NEED A CROSS COMPILER?
> There are several advantages of using cross compiler. Some of them are described as
follows
> By using this compilers not only can development of complex embedded systems be
completed in a fraction of the time, but reliability is improved, and maintenance is easy.
> Knowledge of the processor instruction set is not required.
> Register allocation and addressing mode details are managed by the compiler.
> The ability to combine variable selection with specific operations improves program
readability.
> Keywords and operational functions that more nearly resemble the human thought process
can be used.
26
> Program development and debugging times are dramatically reduced when compared to
assembly language programming.
> The library files that are supplied provide many standard routines (such as formatted
output, data conversions, and floating-point arithmetic) that may be incorporated into your
application.
> Existing routine can be reused in new programs by utilizing the modular programming
techniques available with C.
> The C language is very portable and very popular. C compilers are available for almost all
target systems. Existing software investments can be quickly and easily converted from or
adapted to other processors or environments.
> Now after going through the concept of compiler and cross compilers lets we start with
Keil C cross compiler.
4.5KEIL C CROSS COMPILER: -
> Keil is a German based Software development company. It provides several
development tools like
> IDE (Integrated Development environment)
> Project Manager
> Simulator
> Debugger
> C Cross Compiler , Cross Assembler, Locator/Linker
> Keil Software provides you with software development tools for the 8051 family of
microcontrollers. With these tools, you can generate embedded applications for the multitude
of 8051 derivatives.
> The keil 8051 tool kit includes three main tools, assembler, compiler and linker.
> An assembler is used to assemble your 8051 assembly program
> A compiler is used to compile your C source code into an object file
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> A linker is used to create an absolute object module suitable for your in-circuit emulator.
8051 project development cycle: - these are the steps to develop 8051 project using keil
Create source files in C or assembly.
Compile or assemble source files.
Correct errors in source files.
Link object files from compiler and assembler.
Test linked application.
Now let us start how to work with keil.
To open keil software click on start menu then program and then select keil2 .You can see
three different windows on the screen. 1) project work space window 2) editing window 3)
output window. Project workspace window is for showing all the related files connected with
your project.
Editing window is the place where you will edit the code
Output window will show the output when you compile or build or run your project.
Now to start with new project follow the steps
Click on project menu and select new project
You will be asked to create new project in specific directory
Just move to your desired directory and there create a new folder for your project
named "first".
Give the name of project as "test". By default it will be saved as *.v2 extension.
Now you will be asked to chose your target device for which you want to write the
program.
Scroll down the cursor and select generic from list. expand the list and select 8051
When you click OK, you will be asked to add startup code and file to your project folder.
click yes. Now on your screen expand target1 list fully.
Now click on file menu and select new file. editor window will open. Now you can
start writing your code.
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As you start writing program in C, same way here also you have to first include the
header file. Because our target is 8051 our header file will be "reg51.h"
If you scroll down cursor you will see that all the SFRs like P0-P3, TCON, TMOD,
ACC, bit registers and byte registers are already defined in this header file. so one can
directly use these register names in coding
Now you can write your program same as c language starting with void main()
After completing the code save the file in project folder with ".c" extension.
Now right click on "source group 1" in project workspace window. select "add files to
source group 1"
Select the C file you have created and click add button
you will see that the c file has been added in source group
Now to compile the program from project menu select "build target". In the output
window you will see the progress
If there is any compilation error then target will not be created. Remove all the errors
and again build the target till you find "0 Error(s)"
Now you are ready to run your program. from debug menu select "start/stop debug
session"
You will see your project workspace window now shows most of the SFRs as well as
GPRs r0-r7. Also one more window is now opened named "watches". in this window you
can see different variable values.
If there is any compilation error then target will not be created. Remove all the errors
and again build the target till you find "0 Error(s)"
Now you are ready to run your program. from debug menu select "start/stop debug
session"
You will see your project workspace window now shows most of the SFRs as well as
GPRs r0-r7. Also one more window is now opened named "watches". in this window you
can see different variable values.
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KEIL WORK SPACE
To add variable in watch window go to "watch#1" tab. then type F2 to edit and type
the name of your variable
If you want to see the output on ports go to peripheral menu and select I/O ports.
Select the desire port. you can give input to port pins by checking or unchecking any check
box. Here the check mark means digit 1 and no check mark means 0. the output on the pin
will be shown in same manner
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to run the program you can use any of the option provided "go", "step by step", "step
forward", "step over" etc.
Now after testing your program you need to down load this program on your target
board that is 8051. for this you have to create hex file
To create hex file first stop debug session. Again you will be diverted to project
workspace window.
Right click on "target 1" and select "option for target 1". Following window will
appear.
CONVERSION TO HEXADECIMAL FILE
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5. SOURCE CODE
#include <AT89X52.H> #include <smcl_lcd.h>
void ser_init(); void ser_out(unsigned char); void ser_conout(unsigned char*,unsigned char);
sbit light = P1^0; sbit fan = P1^1; sbit tv = P1^2; sbit radio = P1^3; unsigned char i,v[80],status,k;
void main() {
lcd_init(); ser_init(); ser_out('A');ser_out('T');ser_out(0x0d);del();ser_conout("AT+CMGF=1",9);ser_out(0x0d);del();ser_conout("AT+CPMS=",8);ser_out('"'); ser_out('S'); ser_out('M'); ser_out('"'); ser_out(0x0d); del(); {
i=1;status=ES=0;
ser_conout("AT+CMGR=1",9);ser_out(0x0d); EA=ES=1; del();del(); ES=0; if(i>65) {for(k=60; k<=70; k++) {
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if(v[k]=='1' && v[k+1]=='o' && v[k+2]=='n') {status=1; goto end;if(v[k]=='1' && v[k+1]=='o' && v[k+2]=='f' && v[k+3]=='f') {status=2; goto end;}if(v[k]=='2' && v[k+1]=='o' && v[k+2]=='n') {status=3; goto end;}if(v[k]=='2' && v[k+1]=='o' && v[k+2]=='f' && v[k+3]=='f') {status=4; goto end;}if(v[k]=='3' && v[k+1]=='o' && v[k+2]=='n') {status=5; goto end;}if(v[k]=='3' && v[k+1]=='o' && v[k+2]=='f' && v[k+3]=='f') {status=6; goto end;}if(v[k]=='4' && v[k+1]=='o' && v[k+2]=='n') {status=7; goto end;}if(v[k]=='4' && v[k+1]=='o' && v[k+2]=='f' && v[k+3]=='f') {status=8; goto end;}}status=0;end:if(status) {command(0xc0);write(v[k]);write(v[k+1]);write(v[k+2]);write(v[k+3]); }ser_conout("AT+CMGD=1",9); ser_out(0x0d); del();i=1;}
if(status==1) light=0;
else if(status==2) light=1;
else if(status==3) fan = 0;
else if(status==4) fan = 1;
else if(status==5) tv = 0;
else if(status==6) tv = 1;
else if(status==7) radio=0;
else if(status==8) radio=1;
}}
void ser_init(){
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EA=1; ES=1; SCON = 0X50; TMOD = 0X20; TH1 = 0XFD;TR1 = 1; EX0 = 1; IT0=1;
}
void ser_out(unsigned char val){
SBUF = val;delay (500);SCON = 0X50;delay(8000);
}
void ser_conout(unsigned char*dat,unsigned char ln){ unsigned char i; for(i=0;i<ln;i++)
{ ser_out(dat[i]); }
}
void ser_int(void) interrupt 4{ if (RI) { RI=0; v[i]=SBUF; i++;
}}
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5.1 FLOW CHART
35
If
END
if(v[k]=='1' && v[k+1]=='o' && v[k+2]=='f' && v[k+3]=='f') {status=2; goto end;}
if(v[k]=='2' && v[k+1]=='o' && v[k+2]=='n') {status=3; goto end;}
if(v[k]=='2' && v[k+1]=='o' && v[k+2]=='f' && v[k+3]=='f') {status=4; goto end;}
if(v[k]=='3' && v[k+1]=='o' && v[k+2]=='n') {status=5; goto end;}
if(v[k]=='3' && v[k+1]=='o' && v[k+2]=='f' && v[k+3]=='f') {status=6; goto end;}
f(v[k]=='4' && v[k+1]=='o' && v[k+2]=='n') {status=7; goto end;}
if(v[k]=='4' && v[k+1]=='o' && v[k+2]=='f' && v[k+3]=='f') {status=8; goto end;}
Checking the received message from mobile
To initialize the Microcontroller Registers
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Ser _init
{
EA=1; /* this pin enable for interrupt function */
ES=1; /* this pin enable for serial interrupt function */
SCON=0X50; // this for 8 bit data transreceive serially
TMOD=0X20; // timer1 select
TH1=0XFD; 9600 baud rate data transreceive serially
TR1=1; // timer on
EX0=1;IT0=1;
END
Ser_out
{
SBUF = val; // single data transmit to mobile function using SBUF registerdelay(500);
SCON = 0X50;
delay(8000);
Data Transfer to Mobile
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END
Ser_conout
{
for(i=0;i<ln;i++) {
ser_out(dat[i]);
}
Unsigned character i;
ENDS
6. ADVANTAGES,DISADVANTAGES&APPLICATIONS
6.1ADVANTAGES
1. We can operate the devices from any distance.
2. Low Cost
3. Low power Consumption.
6.2 DISADVANTAGES
1. If there is no network at that particular time we can’t transfer the message
ON the device or OFF the device.
2. Without balance in the phone we cannot transfer the message.
3. This project operates only when there is power supply.
6.3 APPLICATIONS:
1. Used in Industrial Applications.
2. Used in long distance Applications.
3. Used in fields to control the motors.
4. In Home Appliances such as Water Heaters, Room Heaters and Air conditioners.
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7. RESULT AND CONCLUSION
7.1 RESULT
In this project we interfaced Mobile and Microcontroller with the help of RS232
level converter and controlled the operation of four devices(LED’S) using four Relay circuits
by sending an SMS to the mobile which is interfaced to the Microcontroller. We used two
mobiles for transferring the message using GSM Technology. Only mobiles with AT
commands can be interfaced with the controller.
7.2 CONLUSION
Power can be saved by controlling the machines ‘on’ and ‘off’ condition with a
single SMS. This project can be further enhanced by connecting batteries to the power supply
in case of power cut. Further an acknowledgement from the machine on its ‘on’ and ‘off’
condition by modifying the code can be done.
Future scope of this project can be done by connecting sensors to the
microcontroller which can sense the rise in temperature, detect smoke, fire and automatically
generate an SMS to alert the user.
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8. REFERENCES
1. Using SMS in Mobile Phone for Home Appliances Controlling Through PC Parallel Port
Interfacing by Fadhil T. Aula, University of Salahaddin, College of Engineering, and
Electrical Engineering Department. Erbil, Iraq
2. SMS Based Wireless Home Appliance Control System (HACS) for Automating
Appliances and Security by Malik Sikandar Hayat Khiyal, Aihab Khan, and Erum Shehzadi
Software Engineering Dept., Fatima Jinnah Women University, Rawalpindi, Pakistan.
3. System integration of WAP and SMS for home network system by Chi-Hsiang Wu and
Rong-Hong Jan Department of Computer and Information Science, National Chiao Tung
University, 1001 Ta Hsueh Rd., Hsinchu 30050, Taiwan.
4. Remote-Controllable Power Outlet System for Home Power Management by Chia-
Hung Lien; Ying-Wen Bai; Ming-Bo Lin; at Nat. Taiwan Univ. of Sci. & Technol.,
Taipei in Consumer Electronics, IEEE Transactions on Nov. 2007 Volume: 53 Sponsored
by: IEEE Consumer Electronics Society.
5. SMS remote control system for household appliances based on GR47 by WU Zhi-hui,
CHEN Long-dao, YE Qiang (College of Electrical Engineering, Zhejiang University,
Hangzhou 310027, China).
6. Micro Controllers by Deshmukh, Tata McGraw Hill Edition.
7. Microcontrollers (Theory & Applications) by A.V. Deshmuk, WTMH, 2005.
8. The 8051 Microcontroller and Embedded Systems by Mazidi and Mazidi,PHI, 2000.
9. Microcontrollers Architecture, Programming, Interfacing and System Design by Raj
Kamal, Pearson Education, 2005. Microcontroller and Embedded Systems by JaniceGillispie
Mazidi, Rolin D.Mc Kinlay Pearson Edition Inc .2 nd Edition, 2008.
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