ATM SECURITY USING GSM AND MEMS CHAPTER 1 INTRODUCTION 1.1 INTRODUCTION The overview of this project is to design MEMS and GSM based ATM SECURITY system using AT89S52. 1.2 AIM OF THE PROJECT To enhance the security system of present existing ATM machine. 1.3 METHODOLOGY The Project ‘Atm security system using gsm and mems module ’ is designed using MEMS technology. According to this technology the communication takes place between two devices MEMS and microcontroller. The MEMS is a sensor device which identifies the tilt produced by the atm machine due to the irregular movement that occur during theft. This project makes best use of MEMS as a sensor device which identifies the tilt produced by the atm machine due to the irregular movement that occur.. The project basically consists of a MEMS sensor which identifies the tilt by the machine and activates S.R.T.I.S.T 1
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ATM SECURITYUSING GSM AND MEMS
CHAPTER 1
INTRODUCTION
1.1 INTRODUCTION
The overview of this project is to design MEMS and GSM based ATM
SECURITY system using AT89S52.
1.2 AIM OF THE PROJECT
To enhance the security system of present existing ATM machine.
1.3 METHODOLOGY
The Project ‘Atm security system using gsm and mems module ’ is designed
using MEMS technology. According to this technology the communication takes
place between two devices MEMS and microcontroller.
The MEMS is a sensor device which identifies the tilt produced by the atm
machine due to the irregular movement that occur during theft.
This project makes best use of MEMS as a sensor device which identifies the
tilt produced by the atm machine due to the irregular movement that occur..
The project basically consists of a MEMS sensor which identifies the tilt by
the machine and activates the microcontroller to start the following sequence in which
shutting the door using stepper motor and sending sms to vigilance system using gsm
is involved.
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1.4. SIGNIFICANCE
This System stops any sort of robbery by taking MEMS as its input functional
bock. It’s the MEMS that is activating the total project by identifying the tilt caused
by the thief during breaking down the ATM machine. Once the micro controller is
activated the following sequence is started which involves shutting of the door using
stepper motor and alerting the vigilance system by a sms using GSM .
1.5 BLOCK DIAGRAM
Fig.1.1
Fig 1.1 Block Diagram of the Project
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AT89S52
LCD DISPL
GSM MODEM
MAX232
ADC0804
MEMS SENSOR
RELAY
MOTOR
POWER SUPPLY
ATM SECURITYUSING GSM AND MEMS
1.6 BLOCK DIAGRAM DESCRIPTION
The hardware involved in this project is a Power Supply, a LCD to display the
concerned information, a GSM is interfaced to the Microcontroller through MAX
232, MEMS is interfaced through ADC 0804.
While execution, the tilt identified by the mems activates the microcontroller.
The microcontroller then starts the following sequence, it gives command to shut
down the door in order to avoid the thief to run away and also a sms is sent to the
vigilance system to alert them so that they can approach to the place as soon as
possible to catch the burglar.
This Project mainly consists of Power Supply section, Microcontroller section,
Mems section, GSM section, LCD display section, Max 232 serial driver section,
ADC 0804 section, Motor section and Relay section.
1.6.1 Power Supply Section
This section is meant for supplying Power to all the sections mentioned above.
It basically consists of a Transformer to step down the 230V ac to 9V ac followed by
diodes. Here diodes are used to rectify the ac to dc. After rectification the obtained
rippled dc is filtered using a capacitor Filter. A positive voltage regulator is used to
regulate the obtained dc voltage.
1.6.2 Microcontroller Section
This section forms the control unit of the whole project. This section basically
consists of a Microcontroller with its associated circuitry like Crystal with capacitors,
Reset circuitry, Pull up resistors (if needed) and so on. The Microcontroller forms the
heart of the project because it controls the devices being interfaced and communicates
with the devices according to the program being written.
1.6.3 MEMS Section
This is the input functional block which is used to identify the tilt that are
occurred in the atm machine when a thief tries to break open the atm machine.
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1.6.4 ADC 0804 Section
The ADC0808 data acquisition component is a monolithic CMOS device with
an 8-bit analog-to-digital converter, 8-channel multiplexer and microprocessor
compatible control logic. The 8-bit A/D converter uses successive approximation as
the conversion technique. The converter features a high impedance chopper stabilized
comparator, a 256R voltage divider with analog switch tree and a successive
approximation register. The 8-channel multiplexer can directly access any of 8-single-
ended analog signals. The device eliminates the need for external zero and full-scale
adjustments.
1.6.5 GSM Section
GSM (Global System for Mobile communications) is a cellular network,
which means that mobile phones connect to it by searching for cells in the immediate
vicinity. GSM networks operate in four different frequency ranges. Most GSM
networks operate in the 900 MHz or 1800 MHz bands.
1.6.6 MAX 232 Section
The microcontroller can communicate with the serial devices using its single
Serial Port. The logic levels at which this serial port operates is TTL logics. But some
of the serial devices operate at RS 232 Logic levels. For example PC and Smart Card
Reader etc. So in order to communicate the Microcontroller with either Smart Card
Reader or PC, a mismatch between the Logic levels occurs. In order to avoid this
mismatch, in other words to match the Logic levels, a Serial driver is used. And MAX
232 is a Serial Line Driver used to establish communication between microcontroller
and PC (or Smart Card Reader)
1.6.7 LCD Display Section
This section is basically meant to show up the status of the project. This
project makes use of Liquid Crystal Display to display / prompt for necessary
information.
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1.6.8 Motor Section
A stepper motor is an electromechanically device which converts electrical
pulses into discrete mechanical movements. The shaft or spindle of a stepper motor
rotates in discrete step increments when electrical command pulses are applied to it in
the proper sequence. The motors rotation has several direct relationships to these
applied pulses is directly related to the direction of motor shafts rotation. The speed of
the motor shafts rotation is directly related to the frequency of the input pulses and the
length of rotation is directly related to the number of input pulses applied.
1.6.9 Relay Section
A relay is an electrical switch that opens and closes under the control of
another electrical circuit. In the original form, the switch is operated by an
electromagnet to open or close one or many sets of contacts. A relay is able to control
an output circuit of higher power than the input circuit, it can be considered to be, in a
broad sense, a form of an electrical amplifier.
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CHAPTER 2
LITERATURE REVIEW
2.1 INTRODUCTION TO EMBEDDED SYSTEMS
Embedded system is a combination of software and hardware designed and
programmed to perform one/more particular task(s). The hardware is designed for
specific application and then software is embedded in this hardware to perform the
task. Both software and hardware are dedicated to that particular application. The
heart of the system is either processor or controller. Processor / controller may be
general purpose or special purpose that controls whole system.
There may be more than one processor/controller if system is complex. It may
be possible that there is one general purpose processor / controller and one or more
special purpose processors / controllers. For example in 3G (or 4G) cell phones there
is one general purpose processor that handles user commands, memory and display
etc. And there are special purpose processors like DSP for voice communication and
network management, display controller to generate real and reach images on color
LCD screen.
An embedded system is a special-purpose system in which the computer is
completely encapsulated by or dedicated to the device or system it controls.
Physically embedded systems range from portable devices such as digital watches and
MP3 players, to large stationary installations like traffic lights, factory controllers, or
the systems controlling nuclear power plants. In terms of complexity embedded
systems can range from very simple with a single microcontroller chip, to very
complex with multiple units, peripherals and networks mounted inside a large chassis
or enclosure.
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2.1.1 Application Areas
Nearly 99 per cent of the processors manufactured end up in embedded systems.
• Consumer appliances
• Office automation
• Industrial automation:
• Medical electronics.
• Telecommunications
• Wireless technologies
• Security& finance
Examples of embedded systems
Calculators
Laser Printer
Security Systems
Musical Instruments
Medical Equipment's
Automatic Teller Machines (ATMs)
Cellular telephones and telephone switches
Inertial guidance systems for aircraft and missiles
Computer peripherals such as routers and printers
engine controllers and antilock brake controllers for automobiles
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2.2 MICROCONTROLLER AND MICROPROCESSOR
The prime use of a microcontroller is to control the operation of a
machine using fixed programs that is stored in ROM that doesn't change
over the life time of the system
Processors have most of their op-codes moving data from external
memory to the CPU
Generally controllers move data and code from internal memory to
ALU
Processors have most of their instructions operating on a byte
Controllers on the other hand, have many bit handling instructions
making it ideal for control applications.
2.3 MICROCONTROLLER
A Micro controller consists of a powerful CPU tightly coupled with memory
RAM, ROM or EPROM), various I / O features such as Serial ports, Parallel Ports,
Timer/Counters, Interrupt Controller, Data Acquisition interfaces-Analog to Digital
Converter (ADC), Digital to Analog Converter (ADC), everything integrated onto a
single Silicon Chip.
It does not mean that any micro controller should have all the above said
features on chip, Depending on the need and area of application for which it is
designed, the ON-CHIP features present in it may or may not include all the
individual section said above.
Any microcomputer system requires memory to store a sequence of
instructions making up a program, parallel port or serial port for communicating with
an external system, timer / counter for control purposes like generating time delays,
Baud rate for the serial port, apart from the controlling unit called the Central
Processing Unit.
2.4 ADVANTAGES
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If a system is developed with a microprocessor, the designer has to go for
external memory such as RAM, ROM or EPROM and peripherals and hence the size
of the PCB will be large enough to hold all the required peripherals. But, the micro
controller has got all these peripheral facilities on a single chip so development of a
similar system with a micro controller reduces PCB size and cost of the design.
One of the major differences between a micro controller and a microprocessor
is that a controller often deals with bits , not bytes as in the real world application, for
example switch contacts can only be open or close, indicators should be lit or dark
and motors can be either turned on or off and so forth
2.5 PROBLEM STATEMENT
Enhancing the security system of the atm machine. The present existing
system is not sufficient to stop the thief when he tries to break down the atm machine.
2.6 SOLUTION
If we introduce the project then it would be easy to stop the thief. As the thief
tries to open the machine the MEMS is activated this gives signal to the
microcontroller which shuts the door and alerts the vigilance system.
2.7 DESCRIPTION
In this project, the MEMS sensor is placed in the upper or lower panel of the
atm machine, when a thief tries to open the machine he has to break the panel and
open either the upper panel or lower panel. When he does so the MEMS sensor will
be activated as it reads the tilt produced while lifting the panel, this will activate the
microcontroller. As the microcontroller is activated it then has to start a sequence
which should stop the thief from running away from the machine, for this purpose we
need to shut the door, in order to shut the door we are using a stepper motor, also we
have to alert the vigilance system here we are using GSM to send the SMS.
CHAPTER 3
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AT89S52 MICROCONTROLLER
3.1 AT89S52
3.1.1 A BRIEF HISTORY OF 8051
In 1981, Intel corporation introduced an 8 bit microcontroller called 8051. this
microcontroller had 128 bytes of RAM, 4K bytes of chip ROM, two timers, one serial
port, and four ports all on a single chip. At the time it was also referred as “ A
SYSTEM ON A CHIP”
The 8051 is an 8-bit processor meaning that the CPU can work only on 8 bits
data at a time. Data larger than 8 bits has to be broken into 8 bits pieces to be
processed by the CPU. The 8051 has a total of four I\O ports each 8 bit wide.
There are many versions of 8051 with different speeds and amount of on-chip
ROM and they are all compatible with the original 8051. this means that if you write a
program for one it will run on any of them.
The 8051 is an original member of the 8051 family. There are two other members in the 8051 family of microcontrollers. They are 8052 and 8031. All the
three microcontrollers will have the same internal architecture, but they differ in the
following aspects.
8031 has 128 bytes of RAM, two timers and 6 interrupts.
8051 has 4K ROM, 128 bytes of RAM, two timers and 6
interrupts.
8052 has 8K ROM, 256 bytes of RAM, three timers and 8
interrupts.
3.2 NECESSITY OF MICROCONTROLLERS
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Microprocessors brought the concept of programmable devices and made
many applications of intelligent equipment. Most applications, which do not need
large amount of data and program memory, tended to be costly.
The microprocessor system had to satisfy the data and program requirements
so, sufficient RAM and ROM are used to satisfy most applications .The peripheral
control equipment also had to be satisfied. Therefore, almost all-peripheral chips were
used in the design. Because of these additional peripherals cost will be comparatively
high.
Bulky:
On comparing a board full of chips (Microprocessors) with one chip with all
components in it (Microcontroller).
Debugging:
Lots of Microprocessor circuitry and program to debug. In Micro controller
there is no Microprocessor circuitry to debug.
Slower Development time: As we have observed Microprocessors need a lot of
debugging at board level and at program level, where as, Micro controller do not have
the excessive circuitry and the built-in peripheral chips are easier to program for
operation.
So peripheral devices like Timer/Counter, Parallel programmable port, Serial
Communication Port, Interrupt controller and so on, which were most often used were
integrated with the Microprocessor to present the Micro controller .RAM and ROM
also were integrated in the same chip. The ROM size was anything from 256 bytes to
32Kb or more. RAM was optimized to minimum of 64 bytes to 256 bytes or more.
Microprocessor has following instructions to perform:
1. Reading instructions or data from program memory ROM.
2. Interpreting the instruction and executing it.
3. Microprocessor Program is a collection of instructions stored in a Nonvolatile
memory.
4. Read Data from I/O device
5. Process the input read, as per the instructions read in program memory.
6. Read or write data to Data memory.
7. Write data to I/O device and output the result of processing to O/P device.
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3.3 Introduction to AT89S52
The system requirements and control specifications clearly rule out the use of
16, 32 or 64 bit micro controllers or microprocessors. Systems using these may be
earlier to implement due to large number of internal features. They are also faster and
more reliable but, the above application is satisfactorily served by 8-bit micro
controller. Using an inexpensive 8-bit Microcontroller will doom the 32-bit product
failure in any competitive market place. Coming to the question of why to use 89S52
of all the 8-bit Microcontroller available in the market the main answer would be
because it has 8kB Flash and 256 bytes of data RAM32 I/O lines, three 16-bit
timer/counters, a Eight-vector two-level interrupt architecture, a full duplex serial
port, on-chip oscillator, and clock circuitry.
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. The Flash program memory supports both parallel programming and
in Serial In-System Programming (ISP). The 89S52 is also In-Application
Programmable (IAP), allowing the Flash program memory to be reconfigured even
while the application is running.
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.
3.4 FEATURES
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Compatible with MCS-51® Products
• 8K Bytes of In-System Programmable (ISP) Flash Memory
– Endurance: 1000 Write/Erase Cycles
• 4.0V to 5.5V Operating Range
• Fully Static Operation: 0 Hz to 33 MHz
• 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
PIN DIAGRAM
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FIG 3.1 PIN DIAGRAM OF AT89S52 IC
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Port Pin Alternate Functions
P1.0 T2 (external count input to Timer/Counter 2), clock-out
P1.1 T2EX (Timer/Counter 2 capture/reload trigger and direction control)
ATM SECURITYUSING GSM AND MEMS
3.5 PIN DESCRIPTION
Pin Description
VCC: Supply voltage.
GND: Ground.
Port 0
Port 0 is an 8-bit open drain bi-directional 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 pro-gram and data memory. In this mode,
P0 has internal pullups Port 0 also receives the code bytes during Flash program- mi ng an
d ou tpu t s the c o de b y tes du r i n g pr o g r a m verification. External pullups are
required during program verification.
Port 1
Port 1 is an 8-bit bi-directional I/O port with internal pullups. 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 pullups 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 pullups. In addition, P1.0 and P1.1 can be configured to be the
timer/counter 2 external count input (P1.0/T2) and the timer/counter 2 trigger
input (P1.1/T2EX), respectively, as shown in the following table.
Port 1 also receives the low-order address bytes during
Flash programming and verification
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Port 2
Port 2 is an 8-bit bi-directional I/O port with internal pullups. 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 pullups 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 pullups.Port 2 emits the high-order address byte during fetches from
external program memory and during accesses to external data memory that use
16-bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal
pul- lups when emitting 1s. During accesses to external data memory that use 8-
bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function
Register.Port 2 also receives the high-order address bits and some control signals
during Flash programming and verification.
Port 3
Port 3 is an 8-bit bi-directional I/O port with internal pullups. 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 pullups and can be used as inputs. As inputs,
Port 3 pins that are externally being pulled low will source current (IIL) because of
the pullups. Port 3 also serves the functions of various special features of the
AT89C51, as shown in the following table.
Port 3 also receives some control signals for Flash pro- gramming and verification.
Port Pin Alternate Functions
P3.0 RXD (serial input port)
P3.1 TXD (serial output port)
P3.2 INT0 (external interrupt 0)
P3.3 INT1 (external interrupt 1)
P3.4 T0 (timer 0 external input)
P3.5 T1 (timer 1 external input)
P3.6 WR (external data memory write
P3.7 RD (external data memory read strobe)
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RST
Reset input. A high on this pin for two machine cycles while the oscillator is
running resets the device.
ALE/PROG
Address Latch Enable is an output pulse for latching the low byte of the
address during accesses to external mem- ory. This pin is also the program pulse
input (PROG) during Flash programming.
In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator
frequency and may be used for external timing or clocking Note, however, that
one ALE pulse is skipped during each access to external data memory. If
desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the
bit set, ALE is active only dur-ing a MOVX or MOVC instruction. Otherwise, the
pin is weakly pulled high. Setting the ALE-disable bit has no effect if the
microcontroller is in external execution mode.
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FIG-3.2 Functional block diagram of micro controller
3.6 The 8052 Oscillator and Clock
The heart of the 8051 circuitry that generates the clock pulses by which all
the internal all internal operations are synchronized. Pins XTAL1 And XTAL2 is
provided for connecting a resonant network to form an oscillator. Typically a quartz
crystal and capacitors are employed. The crystal frequency is the basic internal clock
frequency of the microcontroller. The manufacturers make 8051 designs that run at
specific minimum and maximum frequencies typically 1 to 16 MHz.
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Fig-3.3 Oscillator and timing circuit
3.7 MEMORIES
3.7.1 Types of memory:
The 8052 have three general types of memory. They are on-chip memory,
external Code memory and external Ram. On-Chip memory refers to physically
existing memory on the micro controller itself. External code memory is the code
memory that resides off chip. This is often in the form of an external EPROM.
External RAM is the Ram that resides off chip. This often is in the form of standard
static RAM or flash RAM.
a) Code memory
Code memory is the memory that holds the actual 8052 programs that is to be
run. This memory is limited to 64K. Code memory may be found on-chip or off-chip.
It is possible to have 8K of code memory on-chip and 60K off chip memory
simultaneously. If only off-chip memory is available then there can be 64K of off chip
ROM. This is controlled by pin provided as EA
b) Internal RAM
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The 8052 have a bank of 256 bytes of internal RAM. The internal RAM is
found on-chip. So it is the fastest Ram available. And also it is most flexible in terms
of reading and writing. Internal Ram is volatile, so when 8051 is reset, this memory is
cleared. 256 bytes of internal memory are subdivided. The first 32 bytes are divided
into 4 register banks. Each bank contains 8 registers. Internal RAM also contains 256
bits, which are addressed from 20h to 2Fh. These bits are bit addressed i.e. each
individual bit of a byte can be addressed by the user. They are numbered 00h to FFh.
The user may make use of these variables with commands such as SETB and CLR.
Special Function registered memory:
Special function registers are the areas of memory that control specific
functionality of the 8052 micro controller.
a) Accumulator (0E0h)
As its name suggests, it is used to accumulate the results of large no of
instructions. It can hold 8 bit values.
b) B registers (0F0h)
The B register is very similar to accumulator. It may hold 8-bit value. The b
register is only used by MUL AB and DIV AB instructions. In MUL AB the higher
byte of the product gets stored in B register. In div AB the quotient gets stored in B
with the remainder in A.
c) Stack pointer (81h)
The stack pointer holds 8-bit value. This is used to indicate where the next
value to be removed from the stack should be taken from. When a value is to be
pushed onto the stack, the 8052 first store the value of SP and then store the value at
the resulting memory location
d) Data pointer
The SFRs DPL and DPH work together work together to represent a 16-bit
value called the data pointer. It is a 16-bit SFR and also an addressable SFR.
e) Program counter
The program counter is a 16 bit register, which contains the 2 byte address,
which tells the 8052 where the next instruction to execute to be found in memory.
And is incremented each time an instruction is executes. It is not addressable SFR.
f) PCON (power control, 87h)
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The power control SFR is used to control the 8051’s power control modes.
Certain operation modes of the 8051 allow the 8051 to go into a type of “sleep
mode” which consumes much lee power.
g) TCON (timer control, 88h)
The timer control SFR is used to configure and modify the way in which the
8051’s two timers operate.. Additionally, some non-timer related bits are located in
TCON SFR. These bits are used to configure the way in which the external interrupt
flags are activated, which are set when an external interrupt occurs.
h) TMOD (Timer Mode, 89h)
The timer mode SFR is used to configure the mode of operation of each of the
two timers. Using this SFR your program may configure each timer to be a 16-bit
timer, or 13 bit timer, 8-bit auto reload timer, or two separate timers. Additionally
you may configure the timers to only count when an external pin is activated or to
count “events” that are indicated on an external pin.
i) TO (Timer 0 low/high, address 8A/8C h)
These two SFRs taken together represent timer 0. Their exact behavior
depends on how the timer is configured in the TMOD SFR; however, these timers
always count up. What is configurable is how and when they increment in value.
j) T1 (Timer 1 Low/High, address 8B/ 8D h)
These two SFRs, taken together, represent timer 1. Their exact behavior
depends on how the timer is configured in the TMOD SFR; however, these timers
always count up..
k) P0 (Port 0, address 90h, bit addressable)
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This is port 0 latch. Each bit of this SFR corresponds to one of the pins on a
micro controller. Any data to be outputted to port 0 is first written on P0 register. For
e.g., bit 0 of port 0 is pin P0.0, bit 7 is pin p0.7. Writing a value of 1 to a bit of this
SFR will send a high level on the corresponding I/O pin whereas a value of 0 will
bring it to low level.
l) P1 (port 1, address 90h, bit addressable)
This is port latch1. Each bit of this SFR corresponds to one of the pins on a
micro controller. Any data to be outputted to port 0 is first written on P0 register. For
e.g., bit 0 of port 0 is pin P1.0, bit 7 is pin P1.7. Writing a value of 1 to a bit of this
SFR will send a high level on the corresponding I/O pin whereas a value of 0 will
bring it to low level
m) P2 (port 2, address 0A0h, bit addressable):
This is a port latch2. Each bit of this SFR corresponds to one of the pins on a
micro controller. Any data to be outputted to port 0 is first written on P0 register. For
e.g., bit 0 of port 0 is pin P2.0, bit 7 is pin P2.7. Writing a value of 1 to a bit of this
SFR will send a high level on the corresponding I/O pin whereas a value of 0 will
bring it to low level.
n) P3 (port 3, address B0h, bit addressable) :
This is a port latch3. Each bit of this SFR corresponds to one of the pins on a
micro controller. Any data to be outputted to port 0 is first written on P0 register. For
e.g., bit 0 of port 0 is pin P3.0, bit 7 is pin P3.7. Writing a value of 1 to a bit of this
SFR will send a high level on the corresponding I/O pin whereas a value of 0 will
bring it to low level.
o) IE (interrupt enable, 0A8h):
The Interrupt Enable SFR is used to enable and disable specific interrupts. The
low 7 bits of the SFR are used to enable/disable the specific interrupts, where the
MSB bit is used to enable or disable all the interrupts. Thus, if the high bit of IE is 0
all interrupts are disabled regardless of whether an individual interrupt is enabled by
setting a lower bit.
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p) IP (Interrupt Priority, 0B8h)
The interrupt priority SFR is used to specify the relative priority of each
interrupt. On 8051, an interrupt maybe either low or high priority. An interrupt may
interrupt interrupts. For e.g., if we configure all interrupts as low priority other than
serial interrupt. However, if a serial interrupt is executing no other interrupt will be
able to interrupt the serial interrupt routine since the serial interrupt routine has the
highest priority.
q) PSW (Program Status Word, 0D0h)
The program Status Word is used to store a number of important bits that are
set and cleared by 8052 instructions. The PSW SFR contains the carry flag, the
auxiliary carry flag, the parity flag and the overflow flag. Additionally, it also
contains the register bank select flags, which are used to select, which of the “R”
register banks currently in use.
r) SBUF (Serial Buffer, 99h)
SBUF is used to hold data in serial communication. It is physically two
registers. One is writing only and is used to hold data to be transmitted out of 8052 via
TXD. The other is read only and holds received data from external sources via RXD.
Both mutually exclusive registers use address 99h.
I/O ports:
One major feature of a microcontroller is the versatility built into the
input/output (I/O) circuits that connect the 8052 to the outside world. The main
constraint that limits numerous functions is the number of pins available in the 8051
circuit. The DIP had 40 pins and the success of the design depends on the flexibility
incorporated into use of these pins.
PORT 0
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Port 0 pins may serve as inputs, outputs, or, when used together, as a bi
directional low-order address and data bus for external memory. When used for
interfacing with the external memory, the lower byte of address is first sent via
PORT0, latched using Address latch enable (ALE) pulse and then the bus is turned
around to become the data bus for external memory.
PORT 1
Port 1 is exclusively used for input/output operations. PORTS 1 pin have no
dual function. When a pin is to be configured as input, 1 is to be written into the
corresponding Port 1 latch.
PORT 2
Port 2 maybe used as an input/output port. It may also be used to supply a
high –order address byte in conjunction with Port 0 low-order byte to address external
memory.. Port 2 latches remain stable when external memory is addressed, as they do
not have to be turned around (set to 1) for data input as in the case for Port 0.
PORT 3
Port 3 may be used to input /output port. The input and output functions can be
programmed under the control of the P3 latches or under the control of various special
function registers. Unlike Port 0 and Port 2, which can have external addressing
functions and change all eight-port b se, each pin of port 3 maybe individually
programmed to be used as I/O or as one of the alternate functions.
3.8
INTERRUPTS:
The AT89S52 has a total of six interrupt vectors: two external interrupts
(INT0 and INT1), three timer interrupts (Timers0, 1, and 2), and the serial port
S.R.T.I.S.T 24
Pin (SFR) Alternate Use
P3.0-RXD (SBUF) Serial data input
P3.1-TXD (SBUF) Serial data output
P3.2-INTO 0 (TCON.1) External interrupt 0
P3.3 - INTO 1 (TCON.3) External interrupt 1
P3.4 - T0 (TMOD) External Timer 0 input
P3.5 – T1 (TMOD) External timer 1 input
P3.6 - WR External memory write pulse
P3.7 - RD External memory read pulse
ATM SECURITYUSING GSM AND MEMS
interrupt. These interrupts are all shown in Figure 10. Each of these interrupt sources
can be individually enabled or disabled by setting or clearing a bit in Special Function
Register IE. IE also contains a global disable bit, EA, which disables all interrupts at
once. Note that Table 5 shows that bit position IE.6 is unimplemented. In the
AT89S52, bit position IE.5 is also unimplemented.Timer 2 interrupt is generated by
the logical OR of bits TF2 and EXF2 in register T2CON. Neither of these flags is
cleared by hardware when the service routine is vectored to. In fact, the service
routine may have to determine whether it was TF2 or EXF2 that generated the
interrupt, and that bit will have to be cleared in software.The Timer 0 and Timer 1
flags, TF0 and TF1, are set at S5P2 of the cycle in which the timers overflow. The
values are then polled by the circuitry in the next cycle. However, the Timer 2 flag,
TF2, is set at S2P2 and is polled in the same cycle in which the timer overflows
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. S.R.T.I.S.T 26
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CHAPTER 4
MEMS(Micro electro mechanical system)
4.1 Introduction
MEMS which is abbreviated as Micro electro mechanical system is a
combination of mechanical and electrical systems. Its fabricated using micro
fabrication technique. This acts as main functional block in our project. Its sensor
device it has the capability of sensing the slightest tilt produced.
4.2 How it is applied in our project
The mems module is placed in the upper or the lower panel present in the
ATM machine. When a thief tries to open the panels of the ATM machine the tilt
produced during opening the panel is read by the MEMS, this activates the
microcontroller then the following sequence is initiated which includes shutting the
door and alerting the vigilance system by sending a sms through GSM.
4.3 Applications
Scrolling of documents, maps and images larger than the display window.
Web page browsing.
Menu navigation.
Automatic portrait-landscape adaption.
Motion control
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CHAPTER 5
ADC 0804
5.1 Introduction
The ADC0808 data acquisition component is a monolithic CMOS device
with an 8-bit analog-to-digital converter, 8-channel multiplexer and microprocessor
compatible control logic. The 8-bit A/D converter uses successive approximation as
the conversion technique. The converter features a high impedance chopper stabilized
comparator, a 256R voltage divider with analog switch tree and a successive
approximation register. The 8-channel multiplexer can directly access any of 8-single-
ended analog signals. The device eliminates the need for external zero and full-scale
adjustments. Easy interfacing to microprocessors is provided by the latched and
decoded multiplexer address inputs and latched TTL tri-state outputs. The design of
the ADC0808 has been optimized by incorporating the most desirable aspects of
several A/D conversion techniques. The ADC0808 offers high speed, high accuracy,
minimal temperature dependence, excellent long-term accuracy and repeatability, and
consumes minimal power. These features make this device ideally suited to
applications from process and machine control to consumer and automotive
applications.
5.2 Features
1. Easy interface to all microprocessors
2. Operates ratio metrically or with 5 VDC or analog span
adjusted voltage reference
3. No zero or full-scale adjust required
4. 8-channel multiplexer with address logic
5. 0V to 5V input range with single 5V power supply
6. Outputs meet TTL voltage level specifications
7. Standard hermetic or molded 28-pin DIP package
8. 28-pin molded chip carrier package
9. ADC0808 equivalent to MM74C949
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5.3 Key Specifications
1. Resolution 8 Bits
2. Total Unadjusted Error ±1/2 LSB and ±1 LSB
3. Single Supply 5 VDC
4. Low Power 15 mW
5. Conversion Time 100 µs
Figure 5.1 Pin diagram:
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Fig 5.2 Molded chip carrier package
5.4 Types of ADC
Digital-Ramp ADC
Successive Approximation ADC
Flash ADC
5.4.1 Digital-Ramp ADC:
Conversion from analog to digital form inherently involves comparator
action where the value of the analog voltage at some point in time is compared with
some standard. A common way to do that is to apply the analog voltage to one
terminal of a comparator and trigger a binary counter which drives a DAC. The output
of the DAC is applied to the other terminal of the comparator. Since the output of the
DAC is increasing with the counter, it will trigger the comparator at some point when
its voltage exceeds the analog input. The transition of the comparator stops the binary
counter, which at that point holds the digital value corresponding to the analog
voltage.
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Fig 5.3 Digital Ramp adc
5.4.2 Successive Approximation ADC:The successive approximation ADC is much faster than the digital ramp ADC
because it uses digital logic to converge on the value closest to the input voltage. A
comparator and a DAC are used in the process. A flowchart explaining the working is
shown in the figure below.
Fig 5.4 Illustration of 4-bit SAC with 1 volt step size
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Fig 5.5 Flash ADC:
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Illustrated is a 3-bit flash ADC with resolution 1 volt (after Tocci). The
resistor net and comparators provide an input to the combinational logic circuit, so the
conversion time is just the propagation delay through the network - it is not limited by
the clock rate or some convergence sequence. It is the fastest type of ADC available,
but requires a comparator for each value of output (63 for 6-bit, 255 for 8-bit, etc.)
Such ADCs are available in IC form up to 8-bit and 10-bit flash ADCs (1023
comparators) are planned. The encoder logic executes a truth table to convert the
ladder of inputs to the binary number output.
5.5 Applications
AD converters are used virtually everywhere where an analog signal has to be
processed, stored, or transported in digital form. Fast video ADCs are used, for
example, in TV tuner cards. Slow on-chip 8, 10, 12, or 16 bit ADCs are common in
microcontrollers. Very fast ADCs are needed in digital oscilloscopes, and are crucial
for new applications like software defined radio and in music recording. ADC's
numbers 975 to 1023 and 0) to the original GSM-900 band. Time division
multiplexing is used to allow eight full-rate or sixteen half-rate speech channels per
radio frequency channel. There are eight radio timeslots (giving eight burst periods)
grouped into what is called a TDMA frame. Half rate channels use alternate frames in
the same timeslot. The channel data rate is 270.833 kbit/s, and the frame duration is
4.615 ms.
6.2 GSM Advantages
GSM also pioneered a low-cost, to the network carrier, alternative to voice
calls, the Short t message service (SMS, also called "text messaging"), which is now
supported on other mobile standards as well. Another advantage is that the standard
includes one worldwide Emergency telephone number, 112. This makes it easier for
international travelers to connect to emergency services without knowing the local
emergency number.
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6.3 The GSM Network
GSM provides recommendations, not requirements. The GSM specifications
define the functions and interface requirements in detail but do not address the
hardware. The GSM network is divided into three major systems: the switching
system (SS), the base station system (BSS), and the operation and support system
(OSS).
Fig 6.1 GSM Network
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6.3.1 The Switching System:
The switching system (SS) is responsible for performing call processing and
subscriber-related functions. The switching system includes the following functional
units.
Home location register (HLR): The HLR is a database used for storage and
management of subscriptions. The HLR is considered the most important
database, as it stores permanent data about subscribers, including a
subscriber's service profile, location information, and activity status. When an
individual buys a subscription from one of the PCS operators, he or she is
registered in the HLR of that operator.
Mobile services switching center (MSC): The MSC performs the telephony
switching functions of the system. It controls calls to and from other telephone
and data systems. It also performs such functions as toll ticketing, network
interfacing, common channel signaling, and others.
Visitor location register (VLR): The VLR is a database that contains
temporary information about subscribers that is needed by the MSC in order to
service visiting subscribers. The VLR is always integrated with the MSC.
When a mobile station roams into a new MSC area, the VLR connected to that
MSC will request data about the mobile station from the HLR. Later, if the
mobile station makes a call, the VLR will have the information needed for call
setup without having to interrogate the HLR each time.
Authentication center (AUC): A unit called the AUC provides authentication
and encryption parameters that verify the user's identity and ensure the
confidentiality of each call. The AUC protects network operators from
different types of fraud found in today's cellular world.
Equipment identity register (EIR): The EIR is a database that contains
information about the identity of mobile equipment that prevents calls from
stolen, unauthorized, or defective mobile stations. The AUC and EIR are
implemented as stand-alone nodes or as a combined AUC/EIR node.
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6.3.2 The Base Station System (BSS):
All radio-related functions are performed in the BSS, which consists of base
station controllers (BSCs) and the base transceiver stations (BTSs).
BSC: The BSC provides all the control functions and physical links between
the MSC and BTS. It is a high-capacity switch that provides functions such as
handover, cell configuration data, and control of radio frequency (RF) power
levels in base transceiver stations. A number of BSCs are served by an MSC.
BTS: The BTS handles the radio interface to the mobile station. The BTS is
the radio equipment (transceivers and antennas) needed to service each cell in
the network. A group of BTSs are controlled by a BSC.
6.3.3 The Operation and Support System
The operations and maintenance center (OMC) is connected to all equipment
in the switching system and to the BSC. The implementation of OMC is called the
operation and support system (OSS). The OSS is the functional entity from which the
network operator monitors and controls the system. The purpose of OSS is to offer the
customer cost-effective support for centralized, regional and local operational and
maintenance activities that are required for a GSM network. An important function of
OSS is to provide a network overview and support the maintenance activities of
different operation and maintenance organizations.
6.4 Additional Functional Elements
Message center (MXE): The MXE is a node that provides integrated voice,
fax, and data messaging. Specifically, the MXE handles short message service,
cell broadcast, voice mail, fax mail, e-mail, and notification.
Mobile service node (MSN): The MSN is the node that handles the mobile
intelligent network (IN) services.
Gateway mobile services switching center (GMSC): A gateway is a node
used to interconnect two networks. The gateway is often implemented in an
MSC. The MSC is then referred to as the GMSC.
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GSM inter-working unit (GIWU): The GIWU consists of both hardware
and software that provides an interface to various networks for data
communications. Through the GIWU, users can alternate between speech and
data during the same call. The GIWU hardware equipment is physically
located at the MSC/VLR.
6.5 GSM Network Areas
The GSM network is made up of geographic areas. As shown in bellow figure, these
areas include cells, location areas (LAs), MSC/VLR service areas, and public land
mobile network (PLMN) areas.
Fig 6.2 GSM Network Areas
6.5.1 Location Areas
The cell is the area given radio coverage by one base transceiver station. The GSM
network identifies each cell via the cell global identity (CGI) number assigned to each
cell. The location area is a group of cells. It is the area in which the subscriber is
paged. Each LA is served by one or more base station controllers, yet only by a single
MSC Each LA is assigned a location area identity (LAI) number.
6.5.2 MSC/VLR service areas
An MSC/VLR service area represents the part of the GSM network that is covered by
one MSC and which is reachable, as it is registered in the VLR of the MSC.
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6.5.3 PLMN service areas
The PLMN service area is an area served by one network operator.
6.6 GSM Specifications
Specifications for different personal communication services (PCS) systems vary among the different PCS networks. Listed below is a description of the specifications and characteristics for GSM.
Frequency band: The frequency range specified for GSM is 1,850 to 1,990
MHz (mobile station to base station).
Duplex distance: The duplex distance is 80 MHz. Duplex distance is the
distance between the uplink and downlink frequencies. A channel has two
frequencies, 80 MHz apart.
Channel separation: The separation between adjacent carrier frequencies. In
GSM, this is 200 kHz.
Modulation: Modulation is the process of sending a signal by changing the
characteristics of a carrier frequency. This is done in GSM via Gaussian
minimum shift keying (GMSK).
Transmission rate: GSM is a digital system with an over-the-air bit rate of
270 kbps.
Access method: GSM utilizes the time division multiple access (TDMA)
concept. TDMA is a technique in which several different calls may share the
same carrier. Each call is assigned a particular time slot.
Speech coder: GSM uses linear predictive coding (LPC). The purpose of
LPC is to reduce the bit rate. The LPC provides parameters for a filter that
mimics the vocal tract. The signal passes through this filter, leaving behind a
residual signal. Speech is encoded at 13 kbps.
6.7 GSM Subscriber Services
Dual-tone multifrequency (DTMF): DTMF is a tone signaling scheme often used
for various control purposes via the telephone network, such as remote control of an
Facsimile group III—GSM supports CCITT Group 3 facsimile. As standard fax
machines are designed to be connected to a telephone using analog signals, a special
fax converter connected to the exchange is used in the GSM system. This enables a
GSM–connected fax to communicate with any analog fax in the network.
Short message services: A convenient facility of the GSM network is the short
message service. A message consisting of a maximum of 160 alphanumeric characters
can be sent to or from a mobile station. This service can be viewed as an advanced
form of alphanumeric paging with a number of advantages. If the subscriber's mobile
unit is powered off or has left the coverage area, the message is stored and offered
back to the subscriber when the mobile is powered on or has reentered the coverage
area of the network. This function ensures that the message will be received.
Cell broadcast: A variation of the short message service is the cell broadcast facility.
A message of a maximum of 93 characters can be broadcast to all mobile subscribers
in a certain geographic area. Typical applications include traffic congestion warnings
and reports on accidents.
Voice mail: This service is actually an answering machine within the network, which
is controlled by the subscriber. Calls can be forwarded to the subscriber's voice-mail
box and the subscriber checks for messages via a personal security code.
Fax mail: With this service, the subscriber can receive fax messages at any fax
machine. The messages are stored in a service center from which they can be
retrieved by the subscriber via a personal security code to the desired fax number
Supplementary Services:
Call forwarding: This service gives the subscriber the ability to forward incoming
calls to another number if the called mobile unit is not reachable, if it is busy, if there
is no reply, or if call forwarding is allowed unconditionally.
Barring of outgoing calls: This service makes it possible for a mobile subscriber to
prevent all outgoing calls.
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Barring of incoming calls: This function allows the subscriber to prevent incoming
calls. The following two conditions for incoming call barring exist: baring of all
incoming calls and barring of incoming calls when roaming outside the home PLMN.
Advice of charge (AoC): The AoC service provides the mobile subscriber with an
estimate of the call charges. There are two types of AoC information: one that
provides the subscriber with an estimate of the bill and one that can be used for
immediate charging purposes. AoC for data calls is provided on the basis of time
measurements.
Call hold: This service enables the subscriber to interrupt an ongoing call and then
subsequently reestablish the call. The call hold service is only applicable to normal
telephony.
Call waiting: This service enables the mobile subscriber to be notified of an
incoming call during a conversation. The subscriber can answer, reject, or ignore the
incoming call. Call waiting is applicable to all GSM telecommunications services
using a circuit-switched connection.
Multiparty service: The multiparty service enables a mobile subscriber to establish a
multiparty conversation—that is, a simultaneous conversation between three and six
subscribers. This service is only applicable to normal telephony.
Calling line identification presentation/restriction: These services supply the
called party with the integrated services digital network (ISDN) number of the calling
party. The restriction service enables the calling party to restrict the presentation. The
restriction overrides the presentation.
Closed user groups (CUGs): CUGs are generally comparable to a PBX. They are a
group of subscribers who are capable of only calling themselves and certain numbers
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CHAPTER 7
MAX 232
7.1 INTRODUCTION
To allow compatibility among data communication equipment made by
various manufacturers, an interfacing standard called RS232 was set by the
Electronics Industries Association (EIA) in 1960. In 1963 it was modified and called
RS232A. RS232B AND RS232C were issued in 1965 and 1969, respectively. Today,
RS232 is the most widely used serial I/O interfacing standard. This standard is used
in PCs and numerous types of equipment. However, since the standard was set long
before the advert of the TTL logic family, its input and output voltage levels are not
TTL compatible. In RS232, a 1 is represented by -3 to -25V, while a 0 bit is +3 to
+25V, making -3 to +3 undefined. For this reason, to connect any RS232 to a
microcontroller system we must use voltage converters such as MAX232 to convert
the TTL logic levels to the RS232 voltage levels, and vice versa. MAX232 IC chips
are commonly referred to as line drivers.
7.2 SERIAL COMMUNICATION
Computers can transfer data in two ways: parallel and serial. In parallel data
transfers, often 8 or more lines (wire conductors) are used to transfer data to a device
that is only a few feet away. Examples of parallel data transfer are printers and hard
disks; each uses cables with many wire strips. Although in such cases a lot of data
can be transferred in a short amount of time by using many wires in parallel, the
distance cannot be great. To transfer to a device located many meters away, the serial
method is used. In serial communication, the data is sent one bit at a time, in contrast
to parallel communication, in which the data is sent a byte or more at a time. Serial
communication of the 8051 is the topic of this chapter.
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The 8051 has serial communication capability built into it, there by making
possible fast data transfer using only a few wires.
If data is to be transferred on the telephone line, it must be converted from
0s and 1s to audio tones, which are sinusoidal-shaped signals. A peripheral device
called a modem, which stands for “modulator/demodulator”, performs this
conversion.
Serial data communication uses two methods, asynchronous and
synchronous. The synchronous method transfers a block of data at a time, while the
asynchronous method transfers a single byte at a time.
In data transmission if the data can be transmitted and received, it is a
duplex transmission. This is in contrast to simplex transmissions such as with
printers, in which the computer only sends data. Duplex transmissions can be half or
full duplex, depending on whether or not the data transfer can be simultaneous. If
data is transmitted one way at a time, it is referred to as half duplex. If the data can go
both ways at the same time, it is full duplex. Of course, full duplex requires two wire
conductors for the data lines, one for transmission and one for reception, in order to
transfer and receive data simultaneously.
7.2.1 Asynchronous serial communication and data framing
The data coming in at the receiving end of the data line in a serial data
transfer is all 0s and 1s; it is difficult to make sense of the data unless the sender and
receiver agree on a set of rules, a protocol, on how the data is packed, how many bits
constitute a character, and when the data begins and endsbits. This is called framing.
In the data framing for asynchronous communications, the data, such as ASCII
characters, are packed between a start bit and a stop bit.
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7.2.2 Start and stop bits
Asynchronous serial data communication is widely used for character-
oriented transmissions, while block-oriented data transfers use the synchronous
method. In the asynchronous method, each character is placed between start and stop
The start bit is always one bit, but the stop bit can be one or two bits. The start bit is
always a 0 (low) and the stop bit (s) is 1 (high)
7.2.3 Data transfer rate
The rate of data transfer in serial data communication is stated in bps (bits
per second). Another widely used terminology for bps is baud rate. However, the
baud and bps rates are not necessarily equal. This is due to the fact that baud rate is
the modem terminology and is defined as the number of signal changes per second.
In modems a single change of signal, sometimes transfers several bits of data. As far
as the conductor wire is concerned, the baud rate and bps are the same, and for this
reason we use the bps and baud interchangeably.
The data transfer rate of given computer system depends on communication
ports incorporated into that system. For example, the early IBMPC/XT could transfer
data at the rate of 100 to 9600 bps. In recent years, however, Pentium based PCS
transfer data at rates as high as 56K bps. It must be noted that in asynchronous serial
data communication, the baud rate is generally limited to 100,000bps.
7.3 RS232 PINS
RS232 cable is commonly referred to as the DB-25 connector. In labeling,
DB-25P refers to the plug connector (male) and DB-25S is for the socket connector
(female). Since not all the pins are used in PC cables, IBM introduced the DB-9
Version of the serial I/O standard, which uses 9 pins only, as shown in table.
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7.3.1 DB-9 pin connector
1 2 3 4 5
6 7 8 9
Table 7.1: Pin Functions of DB-9 Pin Connector
(Note: DCD, DSR, RTS and CTS are active low pins.)
The method used by RS-232 for communication allows for a simple
connection of three lines: Tx, Rx, and Ground.
The three essential signals for 2-way RS-232 Communications are these:
TXD: carries data from DTE to the DCE.
RXD: carries data from DCE to the DTE.
SG: signal ground
S.R.T.I.S.T 45
Pin Description
1 Data carrier detect (DCD)
2 Received data (RXD)
3 Transmitted data (TXD)
4 Data terminal ready(DTR)
5 Signal ground (GND)
6 Data set ready (DSR)
7 Request to send (RTS)
8 Clear to send (CTS)
9 Ring indicator (RI)
ATM SECURITYUSING GSM AND MEMS
The RS232 standard is not TTL compatible; therefore, it requires a line
driver such as the MAX232 chip to convert RS232 voltage levels to TTL levels, and
vice versa. The interfacing of 8051 with RS232 connectors via the MAX232 chip is
the main topic.
The 8051 has two pins that are used specifically for transferring and receiving
data serially. These two pins are called TXD and RXD and a part of the port 3 group
(P3.0 and P3.1). Pin 11 of the 8051 is assigned to TXD and pin 10 is designated as
RXD. These pins are TTL compatible; therefore, they require a line driver to make
them RS232 compatible. One such line driver is the MAX232 chip.
MAX232 converts from RS232 voltage levels to TTL voltage levels, and
vice versa. One advantage of the MAX232 chip is that it uses a +5V power source
which, is the same as the source voltage for the 8051. In the other words, with a
single +5V power supply we can power both the 8051 and MAX232, with no need for
the power supplies that are common in many older systems. The MAX232 has two
sets of line drivers for transferring and receiving data. The line drivers used for TXD
are called T1 and T2, while the line drivers for RXD are designated as R1 and R2. In
many applications only one of each is used.
7.3.2 8051 connection to RS232
Fig.7.1: Connection of Microcontroller with Serial Port Using MAX 232
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The RS232 standard is not TTL compatible; therefore, it requires a Line
Driver such as the MAX232 chip to convert RS232 voltage levels to TTL levels, and
vice versa.
The 8051 has two pins that are used specifically for transferring and receiving
data serially. These two pins are TXD and RXD and are a part of the port 3 (P3.0 and
P3.1). Pin 11 of the 8051 is designated as TXD and pin 10 as RXD. These pins are
TTL compatible; therefore, they require a line driver to make them RS232 compatible.
One such line driver is the MAX232 chip.
MAX232 converts from RS232 voltage levels to TTL voltage levels, and vice
versa. One advantage of the MAX232 chip is that it uses a +5V power source which,
is the same as the source voltage for the 8051. In the other words, with a single +5V
power supply we can power both the 8051 and MAX232, with no need for the power
supplies. The MAX232 has two sets of line drivers for transferring and receiving data.
The line drivers used for TXD are called T1 and T2, while the line drivers for RXD
are designated as R1 and R2. In many applications only one of each is used.
7.4 MAX 232 SERIAL LINEDRIVER
The pin-out diagram of MAX 232 is shown below.
Fig.7.2: MAX 232E Dual Driver/Receiver
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7.4.1 MAX 232 Operating Circuit
Fig.7.3: MAX 232 Operating Circuit
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Table 7.2: Function Tables of MAX 232
Pin 10, 11 form the dual inputs with TTL logic whereas 14, 7 form the outputs
for RS 232 logic. And the 12, 9, 13, 8 form the vice versa inputs and outputs as shown
in fig.
The inputs and outputs of the drivers and receivers are shown in fig above.
CHAPTER 8
LIQUID CRYSTAL DISPLAY
8.1 INTRODUCTION
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 polarizers 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
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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 polarizers, 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 circuits,
and can be powered for long durations.
The LCD s doesn’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.
Changing the display size or the layout size is relatively simple which makes
the LCD’s more customer friendly.
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.
This section describes the operation modes of LCD’s then describe how to
program and interface an LCD to 8051 using Assembly and C.
8.2 LCD OPERATION
In recent years the LCD is finding widespread use replacing LED s (seven-
segment LED s or other multi-segment LED s).This is due to the following reasons:
1. The declining prices of LCDs.
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2. The ability to display numbers, characters and graphics. This is in contrast to
LED which is limited to numbers and a few characters.
3. Incorporation of a refreshing controller into the LCD, there by relieving the
CPU of the task of refreshing the LCD. In the case of LED s, they must be
refreshed by the CPU to keep on displaying the data.
4. Ease of programming for characters and graphics.
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8.3 LCD PIN DESCRIPTION
The LCD discussed in this section has 14 pins. The function of each pin is
given in table.
Fig.8.1: Connection of LCD with Microcontroller
The LCD can display a character successfully by placing the
1. Data in Data Register
2. Command in Command Register of LCD
1. Data corresponds to the ASCII value of the character to be printed. This can
be done by placing the ASCII value on the LCD Data lines and selecting the
Data Register of the LCD by selecting the RS (Register Select) pin.
2. Each and every display location is accessed and controlled by placing
respective command on the data lines and selecting the Command Register of
LCD by selecting the (Register Select) RS pin.
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Pin symbol I/O Description
1 Vss -- Ground
2 Vcc -- +5V power supply
3 VEE -- Power supply to control
contrast
4 RS I RS=0 to select command
register
RS=1 to select data register
5 R/W I R/W=0 for write
R/W=1 for read
6 E I/O Enable
7 DB0 I/O The 8-bit data bus
8 DB1 I/O The 8-bit data bus
9 DB2 I/O The 8-bit data bus
10 DB3 I/O The 8-bit data bus
11 DB4 I/O The 8-bit data bus
12 DB5 I/O The 8-bit data bus
13 DB6 I/O The 8-bit data bus
14 DB7 I/O The 8-bit data bus
Table 8.1: Pin Description for LCD
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Code (hex) Command to LCD Instruction Register
1 Clear display screen
2 Return home
4 Decrement cursor
6 Increment cursor
5 Shift display right
7 Shift display left
8 Display off, cursor off
A Display off, cursor on
C Display on, cursor off
E Display on, cursor on
F Display on, cursor blinking
10 Shift cursor position to left
14 Shift cursor position to right
18 Shift the entire display to the left
1C Shift the entire display to the right
80 Force cursor to beginning of 1st line
C0 Force cursor to beginning of 2nd line
38 2 lines and 5x7 matrix
Table 8.2: LCD Command Codes
8.4 Uses
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.
So in this project, the LCD is used to display the instantaneous information. The
information may be prompting or alerting or instructing the user.
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CHAPTER 9
MOTOR
9.1 Introduction
A stepper motor is an electromechanically device which converts electrical
pulses into discrete mechanical movements. The shaft or spindle of a stepper motor
rotates in discrete step increments when electrical command pulses are applied to it in
the proper sequence. The motors rotation has several direct relationships to these
applied pulses is directly related to the direction of motor shafts rotation. The speed of
the motor shafts rotation is directly related to the frequency of the input pulses and the
length of rotation is directly related to the number of input pulses applied.
9.2 Stepper motor advantages
1. The rotation angle of the motor is proportional to the input pulse
2. The motor has full torque at standstill (if the windings are energized)
3. Precise positioning and repeatability of movement since good stepper motors
have an accuracy of 3-5% of a step and this error is non cumulative from one
step to the next.
4. Excellent response to starting/stopping/reversing.
5. Very reliable since there are no contact brushes in the motor. Therefore the life
of the motor is simply dependant on the life of the bearing.
6. The motors response to digital input pulses provides open-loop control,
making the motor simpler and less costly to control.
7. It is possible to achieve very low speed synchronous rotation with a load that
is directly coupled to the shaft.
8. A wide range of rotational speeds can be realized as the speed is proportional
to the frequency of the input pulses.
9.3 Stepper motor disadvantages
1. Resonances can occur if not properly controlled.
2. Not easy to operate at extremely high speeds.
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9.4 Stepper Motor Types
There are three basic stepper motor types. They are :
• Variable-reluctance
• Permanent-magnet
• Hybrid
9.5 When to Use a Stepper Motor
A stepper motor can be a good choice whenever controlled movement is
required. They can be used to advantage in applications where you need to control
rotation angle, speed, position and synchronism. Because of the inherent advantages
listed previously, stepper motors have found their place in many different
applications. Some of these include printers, plotters, highend office equipment, hard
diskdrives, medical equipment, fax machines, automotive and many more.
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CHAPTER 10
RELAYS
10.1 Introduction
A relay is an electrical switch that opens and closes under the control of another
electrical circuit. In the original form, the switch is operated by an electromagnet to
open or close one or many sets of contacts. A relay is able to control an output circuit
of higher power than the input circuit, it can be considered to be, in a broad sense, a
form of an electrical amplifier.
Fig 10.1 Relay
Relays are usuallly SPDT (single pole double through switch)or DPDT (double
pole double through switch) but they can have many more sets of switch contacts, for
example relays with 4 sets of changeover contacts are readily available.
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10.2 Basic operation of a relay
An electric current through a conductor will produce a magnetic field at right
angles to the direction of electron flow. If that conductor is wrapped into a coil shape,
the magnetic field produced will be oriented along the length of the coil. The greater
the current, the greater the strength of the magnetic field, all other factors being equal.
Fig 10.2 Relay circuit
Inductors react against changes in current because of the energy stored in this
magnetic field. When we construct a transformer from two inductor coils around a
common iron core, we use this field to transfer energy from one coil to the other.
However, there are simpler and more direct uses for electromagnetic fields than the
applications we've seen with inductors and transformers. The magnetic field produced
by a coil of current-carrying wire can be used to exert a mechanical force on any
magnetic object, just as we can use a permanent magnet to attract magnetic objects,
except that this magnet (formed by the coil) can be turned on or off by switching the
current on or off through the coil.
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If we place a magnetic object near such a coil for the purpose of making that object
move when we energize the coil with electric current, we have what is called a
solenoid. The movable magnetic object is called an armature, and most armatures can
be moved with either direct current (DC) or alternating current (AC) energizing the
coil. The polarity of the magnetic field is irrelevant for the purpose of attracting an
iron armature. Solenoids can be used to electrically open door latches, open or shut
valves, move robotic limbs, and even actuate electric switch mechanisms and is used
to actuate a set of switch contacts
10.3 Relays can be categorized according to the magnetic system and operation
10.3.1 Neutral Relays
This is the most elementary type of relay. The neutral relays have a magnetic
coil, which operates the relay at a specified current, regardless of the polarity of the
voltage applied.
10.3.2 Biased Relays
Biased relays have a permanent magnet above the armature. The relay
operates if the current through the coil winding establishes a magneto-motive force
that opposes the flux by the permanent magnet. If the fluxes are in the same direction,
the relay will not operate, even for a greater current through the coil.
10.3.3 Polarized Relays
Like the biased relays, the polarized relays operate only when the current
through the coil in one direction. But there the principle is different. The relay coil has
a diode connected in series with it. This blocks the current in the reverse direction.The
major difference between biased relays and polarized relays is that the former allows
the current to pass through in the reverse direction, but does the not operate the relay
and the later blocks the current in reverse direction. You can imagine how critical
these properties when relays are connected in series to form logic circuits.
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10.3.4 Magnetic Stick Relays or Perm polarized Relays
These relays have a magnetic circuit with high permanence. Two coils, one to
operate (pick up) and one to release (drop) are present. The relay is activated by a
current in the operate coil. On the interruption of the current the armature remains in
picked up position by the residual magnetism. The relay is released by a current
through the release coil.
10.3.5 Slow Release Relays
These relays have a capacitor connected in parallel to their coil. When the
operating current is interrupted the release of relay is delayed by the stored charge in
the capacitor. The relay releases as the capacitor discharges through the coil.
10.3.6 Relays for AC
These are neutral relays and picked up for a.c. current through their coil. These
are very fast in action and used on power circuits of the point motors, where high
current flows through the contacts. A normal relay would be slow and make sparks
which in turn may weld the contacts together.All relays have two operating values
(voltages), one pick-up and the other other drop away. The pick-up value is higher
than the drop away value.
10.4 Applications To control a high-voltage circuit with a low-voltage signal, as in some types of
modems or audio amplifiers,
To control a high-current circuit with a low-current signal, as in the starter
solenoid of an automobile,
To detect and isolate faults on transmission and distribution lines by opening
and closing circuit breakers (protection relays),
To isolate the controlling circuit from the controlled circuit when the two are
at different potentials, for example when controlling a mains-powered device
from a low-voltage switch. They may also be controlled by room occupancy
detectors in an effort to conserve energy,
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To perform logic functions. For example, the boolean AND function is
realised by connecting NO relay contacts in series, the OR function by
connecting NO contacts in parallel. The change-over or Form C contacts
perform the XOR (exclusive or) function. Similar functions for NAND and
NOR are accomplished using NC contacts. The Ladder programming language
is often used for designing relay logic networks.
o Early computing. Before vacuum tubes and transistors, relays were
used as logical elements in digital computers. See ARRA (computer),
Harvard Mark II, Zuse Z2, and Zuse Z3.
o Safety-critical logic. Because relays are much more resistant than
semiconductors to nuclear radiation, they are widely used in safety-
critical logic, such as the control panels of radioactive waste-handling
machinery.
To perform time delay functions. Relays can be modified to delay opening or
delay closing a set of contacts. A very short (a fraction of a second) delay
would use a copper disk between the armature and moving blade assembly.
Current flowing in the disk maintains magnetic field for a short time,
lengthening release time. For a slightly longer (up to a minute) delay, a
dashpot is used. A dashpot is a piston filled with fluid that is allowed to escape
slowly. The time period can be varied by increasing or decreasing the flow
rate. For longer time periods, a mechanical clockwork timer is installed
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CHAPTER 11
REGULATED POWER SUPPLY
11.1 INTRODUCTION
The power supplies are designed to convert high voltage AC mains electricity
to a suitable low voltage supply for electronics circuits and other devices. A RPS
(Regulated Power Supply) is the Power Supply with Rectification, Filtering and
Regulation being done on the AC mains to get a Regulated power supply for
Microcontroller and for the other devices being interfaced to it.
A power supply can by broken down into a series of blocks, each of which
performs a particular function. A d.c power supply which maintains the output voltage
constant irrespective of a.c mains fluctuations or load variations is known as
“Regulated D.C Power Supply”
For example a 5V regulated power supply system as shown below:
Fig.11.1: Block Diagram of the Power Supply
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11.2 TRANSFORMER
A transformer is an electrical device which is used to convert electrical power
from one Electrical circuit to another without change in frequency. Transformers
convert AC electricity from one voltage to another with little loss of power.
Transformers work only with AC and this is one of the reasons why mains electricity
is AC. Step-up transformers increase in output voltage, step-down transformers
decrease in output voltage. Most power supplies use a step-down transformer to
reduce the dangerously high mains voltage to a safer low voltage. The input coil is
called the primary and the output coil is called the secondary. There is no electrical
connection between the two coils; instead they are linked by an alternating magnetic
field created in the soft-iron core of the transformer. The two lines in the middle of
the circuit symbol represent the core. Transformers waste very little power so the
power out is (almost) equal to the power in. Note that as voltage is stepped down
current is stepped up. The ratio of the number of turns on each coil, called the turn’s
ratio, determines the ratio of the voltages. A step-down transformer has a large
number of turns on its primary (input) coil which is connected to the high voltage
mains supply, and a small number of turns on its secondary (output) coil to give a low
output voltage.
Fig.11.2: An Electrical Transformer
Turns ratio = Vp/ VS = Np/NS
Power Out= Power InVS x IS=VP x IP
Vp = primary (input) voltageNp = number of turns on primary coilIp = primary (input) current
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11.3 RECTIFIER
A circuit which is used to convert a.c to dc is known as RECTIFIER. The
process of conversion a.c to d.c is called “rectification”.
11.3.1 Types of Rectifiers
1. Half wave Rectifier
2. Full wave Rectifier
1. Centre tap full wave rectifier.
2. Bridge type full bridge rectifier.
11.3.2 Comparison of rectifier circuits
Parameter
Type of Rectifier
Half wave Full wave Bridge
Number of diodes 1 2 4
PIV of diodes Vm 2Vm Vm
D.C output voltage Vm/ 2Vm/ 2Vm/
Vdc,at no-load 0.318Vm 0.636Vm 0.636Vm
Ripple factor 1.21 0.482 0.482
Ripple frequency f 2f 2f
Rectification
efficiency
0.406 0.812 0.812
Transformer
Utilization
Factor(TUF)
0.287 0.693 0.812
RMS voltage Vrms Vm/2 Vm/√2 Vm/√2
Table 11.1: Comparison of Rectifier Circuits
11.3.3 Full-wave Rectifier
From the above comparison we came to know that full wave bridge rectifier
as more advantages than the other two rectifiers. So, in our project we are using full
wave bridge rectifier circuit.
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11.3.4 Bridge Rectifier
A bridge rectifier makes use of four diodes in a bridge arrangement to
achieve full-wave rectification. This is a widely used configuration, both with
individual diodes wired as shown and with single component bridges where the diode
bridge is wired internally.
A bridge rectifier makes use of four diodes in a bridge arrangement as shown
in fig (a) to achieve full-wave rectification. This is a widely used configuration, both
with individual diodes wired as shown and with single component bridges where the
diode bridge is wired internally.
Fig.11.3: Circuit diagram of Bridge Rectifier
11.3.5 Operation
During positive half cycle of secondary, the diodes D2 and D3 are in
forward biased while D1 and D4 are in reverse biased as shown in the fig(b). The
current flow direction is shown in the fig (b) with dotted arrows.
Fig.11.4. (a): Operation Circuit of Bridge Rectifier
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During negative half cycle of secondary voltage, the diodes D1 and D4 are in
forward biased while D2 and D3 are in reverse biased as shown in the fig(c). The
current flow direction is shown in the fig (c) with dotted arrows.
Fig.11.4. (b): Operation Circuit of Bridger Rectifier
11.4 FILTER
A Filter is a device which removes the a.c component of rectifier output but
allows the d.c component to reach the load
11.4.1 Capacitor Filter
We have seen that the ripple content in the rectified output of half wave
rectifier is 121% or that of full-wave or bridge rectifier or bridge rectifier is 48%
such high percentages of ripples is not acceptable for most of the applications.
Ripples can be removed by one of the following methods of filtering.
(a) A capacitor, in parallel to the load, provides an easier by –pass for the
ripples voltage though it due to low impedance. At ripple frequency and
leave the D.C. to appear at the load.
(b) An inductor, in series with the load, prevents the passage of the ripple
current (due to high impedance at ripple frequency) while allowing the d.c
(due to low resistance to d.c)
(c) Various combinations of capacitor and inductor, such as L-section filter
section filter, multiple section filter etc. which make use of both the
properties mentioned in (a) and (b) above. Two cases of capacitor filter, one
applied on half wave rectifier and another with full wave rectifier.
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Filtering is performed by a large value electrolytic capacitor connected across
the DC supply to act as a reservoir, supplying current to the output when the varying
DC voltage from the rectifier is falling. The capacitor charges quickly near the peak
of the varying DC, and then discharges as it supplies current to the output. Filtering
significantly increases the average DC voltage to almost the peak value (1.4 × RMS
value).
To calculate the value of capacitor(C),
C = ¼*√3*f*r*Rl
Where,
f = supply frequency,
r = ripple factor,
Rl = load resistance
Note: In our circuit we are using 1000µF hence large value of capacitor is
placed to reduce ripples and to improve the DC component.
11.5 REGULATOR
Voltage regulator ICs is available with fixed (typically 5, 12 and 15V) or
variable output voltages. The maximum current they can pass also rates them.
Negative voltage regulators are available, mainly for use in dual supplies.
Most regulators include some automatic protection from excessive current
('overload protection') and overheating ('thermal protection'). Many of the fixed
voltage regulators ICs have 3 leads and look like power transistors, such as the 7805
+5V 1A regulator shown on the right. The LM7805 is simple to use. You simply
connect the positive lead of your unregulated DC power supply (anything from 9VDC
to 24VDC) to the Input pin, connect the negative lead to the Common pin and then
when you turn on the power, you get a 5 volt supply from the output pin.
Fig. 11.5: A Three Terminal Voltage Regulator
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CHAPTER 12
CIRCUIT DESCRIPTION
12.1 INTRODUCTION
ATM security system using GSM and MEMS Modules is one of the hot topics
in embedded systems industry. For providing Security at ATMs GSM and MEMS
Modules are controlled by using ATMEL Processor based AT89S52 Microcontroller.
Probably the most useful thing to know about the global system for mobile
communication is that it is an international standard. If you travel in parts of world,
GSM is only type of cellular service available. Instead of analog services, GSM was
developed as a digital system using TDMA technology.
Micro Electrical Mechanical Systems (MEMS) is the integration of
mechanical elements, sensors, actuators, and electronics on a common silicon
substrate through micro fabrication technology. The broadest requirement for these
very small devices is ability to sense the environment, to collect necessary data and to
create a signal or action to make desired changes to the environment.
In this project ATMEL based AT89S52 Microcontroller monitors MEMS Module ,
GSM and motor. MEMS module is placed on the outer panel of the ATM Machine, if
any tilt is identified by this block, MEMS send a signal to AT89S52 and as the signal
is received, it locks the ATM door and Alert message is send to the Security using
GSM Module.
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12.2 SCHEMATIC DIAGRAM OF THE PROJECT
Fig.12.1: Schematic Diagram of the Project
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12.3 SCHEMATIC DESCRIPTION
Firstly, the required operating voltage for Microcontroller 89S52 is 5V. Hence
the 5V D.C. power supply is needed by the same. This regulated 5V is generated by
first stepping down the 230V to 9V by the step down transformer.
The step downed a.c. voltage is being rectified by the Bridge Rectifier. The
diodes used are 1N4007. The rectified a.c voltage is now filtered using a ‘C’ filter.
Now the rectified, filtered D.C. voltage is fed to the Voltage Regulator. This voltage
regulator allows us to have a Regulated Voltage which is +5V.The rectified; filtered
and regulated voltage is again filtered for ripples using an electrolytic capacitor
100μF. Now the output from this section is fed to 40 th pin of 89S52 microcontroller to
supply operating voltage.
The microcontroller 89S52 with Pull up resistors at Port0 and crystal oscillator
of 11.0592 MHz crystal in conjunction with couple of capacitors of is placed at 18 th
& 19th pins of 89S52 to make it work (execute) properly.
The LCD is interfaced to Microcontroller. The data pins and control pins of
LCD are connected to Port 0 as shown in schematic. The GSM is interfaced to
microcontroller through a voltage level converter i.e. MAX 232.
The GSM o/p & i/p pins i.e. RX and TX are connected to MAX 232 serial
drivers 7th and 13th pins and its output to Microcontroller from 11th & 12th of MAX to
TX and RX pins of Microcontroller.
A Motor is connected across port 2 at 24th pin.
And the main functional input block MEMS is interfaced at port 1,at p1.0 to
p1.7 with 18th to 11th pins of ADC 0804 and in turn this ADC 0804 is connected with
mems at 2nd 3rd and 5th pins.
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12.4 HARDWARE COMPONENTS
The Hardware components used in this project are
Regulated Power Supply
Microcontroller
MEMS Sensor
ADC 0804
GSM
MAX 232
LCD
Motor
Relay
12.5 SOFTWARE COMPONENTS
12.5.1 About Software
Software used is:
*Keil software for C programming
*Express PCB for lay out design
*Express SCH for schematic design
12.5.2 KEIL µVision3
What's New in µVision3?
µVision3 adds many new features to the Editor like Text Templates, Quick
Function Navigation, and Syntax Coloring with brace high lighting Configuration
Wizard for dialog based startup and debugger setup. µVision3 is fully compatible to
µVision2 and can be used in parallel with µVision2.
What is µVision3?
µVision3 is an IDE (Integrated Development Environment) that helps you write, compile, and debug embedded programs. It encapsulates the following components:
A project manager.
A make facility.
Tool configuration.
Editor.
A powerful debugger.
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12.5.3 Express PCB
Express PCB is a Circuit Design Software and PCB manufacturing service.
One can learn almost everything you need to know about Express PCB from the help
topics included with the programs given.
Details: Express PCB, Version 5.6.0
12.5.4 Express SCH
The Express SCH schematic design program is very easy to use. This software
enables the user to draw the Schematics with drag and drop options.
A Quick Start Guide is provided by which the user can learn how to use it.
Details:
Express SCH, Version 5.6.0
12.6 EMBEDDED C
The programming Language used here in this project is an Embedded C
Language. This Embedded C Language is different from the generic C language in
few things like
a) Data types
b) Access over the architecture addresses.
The Embedded C Programming Language forms the user friendly language
with access over Port addresses, SFR Register addresses etc.
Embedded C Data types:
Data Types Size in Bits Data Range/Usage
unsigned char 8-bit 0-255
signed char 8-bit -128 to +127
unsigned int 16-bit 0 to 65535
signed int 16-bit -32,768 to +32,767
sbit 1-bit SFR bit addressable only
Bit 1-bit RAM bit addressable only
sfr 8-bit RAM addresses 80-FFH only
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12.6.1 8051 project development cycle
1. Create source files in C or assembly.
2. Compile or assemble source files.
3. Correct errors in source files.
4. Link object files from compiler and assembler.
5. Test linked application.
The steps to develop 8051 project using keil are
1. Click on the Keil uVision Icon on Desktop
2. Click on the Project menu from the title bar
3. Then Click on New Project
4. Save the Project by typing suitable project name with no extension in u r
own folder sited in either C:\ or D:\
5. Then Click on save button above.
6. Select the component for u r project. i.e. Atmel……
7. Click on the + Symbol beside of Atmel
8. Select AT89C51 as shown below
9. Then Click on “OK”
10. Then Click either YES or NO………mostly “NO”
11. Now your project is ready to USE
12. Now double click on the Target1, you would get another option “Source
group 1” as shown in next page.
13. Click on the file option from menu bar and select “new”
14. The next screen will be as shown in next page, and just maximize it by
double clicking on its blue boarder.
15. Now start writing program in either in “C” or “ASM”
16. For a program written in Assembly, then save it with extension “. asm”
and for “C” based program save it with extension “ C”
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17. Now right click on Source group 1 and click on “Add files to Group
Source”
18. Now you will get another window, on which by default “C” files will
appear.
19. Now select as per your file extension given while saving the file
20. Click only one time on option “ADD”
21. Now Press function key F7 to compile. Any error will appear if so happen.
22. If the file contains no error, then press Control+F5 simultaneously.
23. Then Click “OK”.
24. Now Click on the Peripherals from menu bar, and check your required port
as shown in fig below.
25. Drag the port a side and click in the program file.
26. Now keep Pressing function key “F11” slowly and observe.
{unsigned int i=0,j=0;TH1=0xFA;cmd_lcd(0x01);display_lcd("SENDING SMS...");print("AT+CMGS=");SEND_CHR('"');print(nm);SEND_CHR('"');print("\r\n");delay_ms(500);print("SOMEBODY IS TRYING TO ROBERY");print("\r\n");print("\r\n");i=0;SEND_CHR(0x1A);SEND_CHR(0x1A); //END OF MESSAGE INDICATION. (ctrl + z)delay_ms(500);}