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Electronic voting machine using RFID
1. 1.1 Introduction:
Chapter 1
Introduction to the Project
The term ‘RFID’ stands for Radio Frequency Identification. In recent years
automatic identification procedures (Auto-ID) have become very popular in many
service industries, purchasing and distribution logistics, industry, manufacturing
companies and material flow systems. Automatic identification procedures exist to
provide information about people, animals, goods and products in transit. The
omnipresent barcode labels that triggered a revolution in identification systems some
considerable time ago, are being found to be inadequate in an increasing number of
cases. Barcodes may be extremely cheap, but their stumbling block is their low storage
capacity and the fact that they cannot be reprogrammed. The technically optimal
solution would be the storage of data in a silicon chip.
Radio Frequency Identification (RFID) is a generic term for non-contacting
technologies that use radio waves to automatically identify people or objects. There are
several methods of identification, but the most common is to store a unique serial
number that identifies a person or object on a microchip that is attached to an antenna.
The combined antenna and microchip are called an "RFID transponder" or "RFID tag"
and work in combination with an "RFID reader" (sometimes called an "RFID
interrogator").
1.2Project overview:
In this project we describe the design, construction and operation of a digital
voting machine using RFID system and a microcontroller profoundly.
Here, a RFID card is used for identification of a person before giving his vote
by placing his RFID Card before the RFID Reader module. When the card is placed
before the reader, the details stored with the unique number in the microcontroller will
be checked and will be displayed. If he/she is eligible for voting, they’ll be sent to
voting unit where they will be giving their vote to the any of the parties/candidates
listed only once. If they try to violate any of the rules like giving their vote more than
once or if he/she is not the eligible person, then an alarming Buzzer will be activated.
And at last by pressing the result switch, the Candidate with maximum votes will be
declared as winner or it’ll be displayed ‘Tie’.
1
2. Chapter-2
Block Diagram and its Description
2.1Basic block diagram:
The block diagram comprises of few major blocks as follows,
• Power supply unit
• Voting unit (RFID Module and Microcontroller)
• Conformation Unit (LED/Buzzer)
• Display unit (LCD)
Result
Figure 1 Block Diagram of EVM
2.2 Block diagram description:
2.2.1 Power supply unit:
Power supply is a very important part of electronic circuit this circuit required
fixed +5 V supply so to fix this voltage we needed voltage regulator. In this work we
used IC7805 Voltage regulator whose output is fixed at +5 volts. A voltage regulator
generates a fixed output voltage of a preset magnitude that remains constant regardless
of changes to its input voltage or load conditions. There are two types of voltage
regulators: linear and switching. A linear regulator employs an active (BJT or
MOSFET) pass device (series or shunt) controlled by a high gain differential amplifier.
It compares the output voltage with a precise reference voltage and adjusts the pass
device to maintain a constant output voltage.
2
3. 2.2.2 Voting unit:
It is a combination of two very major units
o RFID Module
o AT mega 16 micro controller.
2.2.2.1 RFID Reader Module and Card:
i) RFID Card:
The RFID card is the Identification card we will be using in this project. RFID
systems are closely related to the smart cards. Like smart card systems, data is stored
on an electronic data-carrying device --- the transponder. However, unlike the smart
card, the power supply to the data-carrying device and thereade3r are achieved
without the use of galvanic contacts, using instead magnetic or electromagnetic fields.
Figure 2 Typical architecture of a microprocessor card.
The underlying technical procedure is drawn from the fields of radio and radar
engineering. Here, the information is carried by radio waves, Dye to the numerous
advantages of RFID systems compared with other identification systems, RFID systems
are now beginning to conquer new mass markets, and one example is the use of
contactless smart cards as tickets for short-distance public transport.
3
4. Figure3RFIDReaderModule(#28140)
ii) RFID Reader module:
A RFID reader is the major section in identification process. It is simply called
as reader module.
a) Components of a RFID system:
An RFID system is always made up of two components (Figure):
• The transponder, which is located on the object to be identified;
• The interrogator or reader, which, depending upon the design and the technology
used, may be a read or write/read device (in this book — in accordance with normal
colloquial usage — the data capture device is always referred to as the reader,
regardless of whether it can only read data or is also capable of writing). A
reader typically contains a radio frequency module (transmitter and receiver), a control
unit and a coupling element to the transponder. In addition, many readers are fitted with
an additional interface (RS 232, RS 485, etc.) to enable them to forward the data
received to another system (PC, robot control system, etc.). The transponder, which
represents the actual data-carrying device of an RFID system, normally consists of a
coupling element and an electronic microchip.
4
5. Figure 4: The reader and transponder are the main components of every RFID system
An RFID system consists of a reader and one or more tags. The reader's antenna
is used to transmit radio frequency (RF) energy. Depending on the tag type, the energy
is "harvested" by the tag's antenna and used to power up the internal circuitry of the tag.
The tag will then modulate the electromagnetic waves generated by the reader in order
to transmit its data back to the reader. The reader receives the modulated waves and
converts them into digital data. In the case of the Parallax RFID Reader Module,
correctly received digital data is sent serially through the SOUT pin.
Figure 5 Flow of process of an RFID system
5
6. The basic layout can be understood by the following diagram.
Figure 6: Basic layout of the RFID data-carrying device, the transponder. Left, inductively
coupled transponder with antenna coil; right, microwave transponder with dipolar antenna
When the transponder, which does not usually possess its own voltage supply
(battery), is not within the interrogation zone of a reader it is totally passive. The
transponder is only activated when it is within the interrogation zone of a reader. The
power required to activate the transponder is supplied to the transponder through the
coupling unit (contactless), as are the timing pulse and data.
6
7. iii) Switching Section:
It comprises of series of switches (We used Tactile switches) allocated for
number of parties present. These switching section will be activated only when it
receives conformation signal from the Micro controller. i.e., only a valid person with
his/her valid RFID card will be able to give his vote.
Figure 7: Graphical Representation of Switching section.
Figure 8: Tactile switches used in switching section.
7
8. Table 1: Comparison of different RFID systems showing their advantages and disadvantages.
8
9. 2.2.2.2CommunicationProtocol:
Implementation and usage of the RFID Reader Module is straightforward.
BASIC Stamp 1, 2, and SX28AC/DP code examples (SX/B) are included at the end of
this documentation.
The RFID Reader Module is controlled with a single TTL-level active-low /ENABLE
pin. When the /ENABLE pin is pulled LOW, the module will enter its active state and
enable the antenna to interrogate for tags. The current consumption of the module will
increase dramatically when the module is active.
A visual indication of the state of the RFID Reader Module is given with the on-board
LED. When the module is successfully powered-up and is in an idle state, the LED will
be GREEN. When the module is in an active state and the antenna is transmitting, the
LED will be RED.
The face of the RFID tag should be held parallel to the front or back face of the antenna
(where the majority of RF energy is focused). If the tag is held sideways (perpendicular
to the antenna) you'll either get no reading or a poor reading. Only one transponder tag
should be held up to the antenna at any time. The use of multiple tags at one time will
cause tag collisions and confuse the reader. The two tags available in the Parallax store
have a read distance of approximately 3 inches. Actual distance may vary slightly
depending on the size of the transponder tag and environmental conditions of the
application.
When a valid RFID transponder tag is placed within range of the activated reader, the
unique ID will be transmitted as a 12-byte ASCII string via the TTL-level SOUT (Serial
Output) pin in the following format:
The start byte and stop byte are used to easily identify that a correct string has
been received from the reader (they correspond to a line feed and carriage return
characters, respectively). The middle ten bytes are the actual tag's unique ID.
All communication is 8 data bits, no parity, 1 stop bit, non-inverted, least
significant bit first (8N1). The baud rate is configured for 2400bps, a standard
communications speed supported by most any microprocessor or PC, and cannot be
changed. The Parallax RFID Reader Module initiates all communication. The Parallax
RFID Reader Module can connect directly to any TTL-compatible UART or to an
RS232-compatible interface by using an external level shifter.
9
10. 2.2.3 Micro controller:
• It is the heart of this project. We used At mega 16 micro controller (Atmel-medium-
16-KB of flash memory).
• It is able to receive unique code from RFID module. Then it checks weather the code
is authorized or not by comparing the received code to already stored code.
• If received code and stored code are matched, then it allows the voter to put his vote
to either of the parties.
• It also displays voter name and weather he has finished giving his vote or not.
2.2.3.1 Pin configuration:
Figure 9: Pin configuration of ATmega 16 Micro Controller
Pin descriptions of ATmaga16L Microcontroller
VCC: Digital supply voltage.
GND: Ground.
Port B (PB7...PB0):
Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port B output buffers have symmetrical drive characteristics with both high
sink and source capability. As inputs, Port B pins that are externally pulled low will
source current if the pull-up resistors are activated. The Port B pins are tri-stated when
10
11. a reset condition becomes active, even if the clock is not running. Port B also serves the
unction’s of various special features of the ATmega16.
Port C (PC7...PC0):
Port C is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port C output buffers have symmetrical drive characteristics with both high
sink and source capability. As inputs, Port C pins that are externally pulled low will
source current if the pull-up resistors are activated. The Port C pins are tri-stated when
a reset condition becomes active, even if the clock is not running. If the JTAG interface
is enabled, the pull-up resistors on pins PC5 (TDI), PC3 (TMS) and PC2 (TCK) will be
activated even if a reset occurs. Port C also serves the functions of the JTAG interface
and other special features of the ATmega16.
Port D (PD7...PD0):
Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port D output buffers have symmetrical drive characteristics with both high
sink and source capability. As inputs, Port D pins that are externally pulled low will
source current if the pull-up resistors are activated. The Port D pins are tri-stated when
a reset condition becomes active, even if the clock is not running. Port D also serves
the functions of various special features of the ATmega16.
Port A (PA7...PA0):
Port A serves as the analog inputs to the A/D Converter. Port A also serves as an 8-bit
bi-directional I/O port, if the A/D Converter is not used. Port pins can provide internal
pull-up resistors (selected for each bit). The Port A output buffers have symmetrical
drive characteristics with both high sink and source capability. When pins PA0 to PA7
are used as inputs and are externally pulled low, they will source current if the internal
pull-up resistors are activated. The Port A pins are tri-stated when a reset condition
becomes active, even if the clock is not running.
RESET:
Reset Input. A low level on this pin for longer than the minimum pulse length will
generate a reset, even if the clock is not running. Shorter pulses are not guaranteed to
generate a reset.
AVCC:
AVCC is the supply voltage pin for Port A and the A/D Converter. It should be
externally connected to VCC, even if the ADC is not used. If the ADC is used, it should
be connected to VCC through a low-pass filter.
AREF:
AREF is the analog reference pin for the A/D Converter.
11
12. XTAL1:-
Input to the inverting Oscillator amplifier and input to the internal clock
operating circuit.
XTAL2:-
Output from the inverting Oscillator amplifier.
2.2.4Conformation unit
From this unit we are able to know that the voter has voted his vote
or not. If the vote is successful a buzzer is beeped. And if the voter is a valid
voter and if he tries to come again the second time after giving his vote, there
will be a long buzzing sound(for 5 sec) from the buzzer. If the voter is not at
all a valid voter then the buzzer will be on for 3 sec. Here we used a 12V
Buzzer shown in the below figure.
12
13. 2.2.5 Display unit:
• For display purpose we use a 20x4 lcd display.
• It can display 80 characters.
• It is able to display Alpha Numeric Characters.
Figure 12: Pin configuration of a 20x4 LCD
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14. Chapter-3
Working and Schematic Diagram
3.1 Working of the circuit:
The high level electronic voting machine built with ATmega16 Micro
controller. The micro controller port D uses for LCD display and port C.0 (pin 22) uses
for voting power or presiding officers button. The candidate button input from Port C.1
– C.4 (pin 23 to 26; 4 candidate). The output LED and buzzer uses Micro controller port
C.5 and C.6. The LCD backlight also connected to port C.7 via a transistor. At the
starting of voting the election commission offices setup the machine at the center. Then
power on the switch and sealed it that nobody can power off. The presiding officer
identifies the original voter of that particular area and pushes the voting power button.
The voting power LED glow then and continues until once press the candidate buttons.
The voter then goes to the secret room where Voting unit placed and press button beside
his candidate symbol. Voter can watch success of voting by glowing confirmation LED
and beep indication. The presiding officer can also hear beep sound watch a confirmation
LED. Same time the voting power goes down and nobody can vote again. Mainly when
presiding officer press voting power button, Micro controller start scanning from pin 23
to pin 26. When get response from a specific pin, increase the counter one of that
candidate and stop scanning. So it is not possible to voting twice or more. All the counter
result store at Micro controller EEPROM. When the voting is under process it will
showed at display “Voting under Process”.
At the end of voting we need to know result. Then election commission or
presiding officer presses the secret key (password). Now the Micro controller shows the
result and supply the power to LCD backlight that it illuminated. If it needs to return
voting process again one should press another secret key. There uses a transistor to
operate buzzer and confirmation LED with proper current. There also uses a voltage
regulator (7805) to supply 5v continuously. Here uses a dry cell 9V battery as power
source. The power consumption of the system is very low (50mW- 150mW varying).
After collected data and need erase recorded data from EEPROM just broken the sealed
on power button and power off the system. Now the system is ready for next election.
The voter is allowed to give his vote to only one party only once by pressing
any one of the switch from the switching section.
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16. 3.3 Printed Circuit Board:
The micro controller and other components are soldered on to a PCB.
The PCB (printed circuit board) is shown below.
A printed circuit board, or PCB, is used to mechanically support and
electrically connect electronic components using conductive pathways,
tracks or signal traces etched from copper sheets laminated onto a non-
conductive substrate. It is also referred to as printed wiring board (PWB)
or etched wiring board. A PCB populated with electronic components is a
printed circuit assembly (PCA), also known as a printed circuit board
assembly (PCBA). Printed circuit boards are used in virtually all but the
simplest commercially produced electronic devices. PCBs are inexpensive,
and can be highly reliable. They require much more layout effort and
higher initial cost than either wire wrap or point-to-point construction, but
are much cheaper and faster for high-volume production; the production
and soldering of PCBs can be done by automated equipment. Much of the
electronics industry's PCB design, assembly, and quality control needs are
set by standards that are published by the IPC organization.
Figure14: PCB layout
16
17. Chapter-4
Hardware Design & Descriptions
4.1 Procedure Followed While Designing:
• Then we programmed the microcontroller using sinaprog software using hex
file.
• Then soldering process was done. After completion of the soldering process
we tested the circuit.
• Still the desired output was not obtained and so troubleshooting was done. In
the process of troubleshooting we found the circuit aptly soldered and
connected and hence came to conclusion that there was error in programming
section which was later rectified and the desired results were obtained.
4.2 List of Components:
Following are the list of components that are used to build the assembly of the
power supply unit, voting unit, display unit and for buzzer.
i) Micro controller Atmega16
ii) RFID module
iii) RFID cards
iv) Max 232 IC
v) 8 MHz crystal
vi) SL100 transistor
vii) IC7805 (Regulator)
viii) 230 to 12 Volts AC step-down transformer
ix) Resistors
x) Capacitors
xi) LED
xii) LCD
17
18. I) Micro controller Atmega16:
Refer to Pg. No: 10
II) RFID module:
Refer to Pg. No: 04
III) RFID cards:
Refer to Pg. No: 03
IV) MAX232 IC:
It is used to convertsignals from an RS-232 serial port to signals suitable for
use in TTL compatible digital logic circuits. The MAX232 is a dual driver/receiver
and typically converts the RX, TX, CTS and RTS signals.
Figure 15: Max232 IC
The drivers provide RS-232 voltage level outputs (approx. ± 7.5 V) from a single + 5 V
supply via on-chip charge pumps and external capacitors. This makes it useful for
implementing RS-232 in devices that otherwise do not need any voltages outside the
0 V to + 5 V range, as power supply design does not need to be made more complicated
just for driving the RS-232 in this case.
18
19. The receivers reduce RS-232 inputs (which may be as high as ± 25 V), to standard 5 V
TTL levels. These receivers have a typical threshold of 1.3 V, and a typical hysteresis
of 0.5 V.
The later MAX232A is backwards compatible with the original MAX232 but may
operate at higher baud rates and can use smaller external capacitors – 0.1 µF in place
of the 1.0 μF capacitors used with the original device.
The newer MAX3232 is also backwards compatible, but operates at a broader voltage
range, from 3 to 5.5 V.
It is helpful to understand what occurs to the voltage levels. When a MAX232
IC receives a TTL level to convert, it changes a TTL logic 0 to between +3 and +15 V,
and changes TTL logic 1 to between -3 to -15 V, and vice versa for converting from
RS232 to TTL. This can be confusing when you realize that the RS232 data
transmission voltages at a certain logic state are opposite from the RS232 control line
voltages at the same logic state.
V) SL100 Transistor:
SL100 is a general purpose, medium power NPN transistor. It is mostly
used as switch in common emitter configuration. The transistor terminals
require a fixed DC voltage to operate in the desired region of its characteristic
curves. This is known as the biasing. For switching applications, SL100 is
biased in such a way that it remains fully on if there is a signal at its base. In
the absence of base signal, it gets turned off completely. The emitter leg of
SL100 is indicated by a protruding edge in the transistor case. The base is
nearest to the emitter while collector lies at other extreme of the casing.
Figure 16: SL100 Transistor
19
20. VI) CrystalOscillator:
A crystal oscillator is an electronic oscillator circuit that uses the mechanical
resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a
very precise frequency. This frequency is commonly used to keep track of time (as in quartz
wrist watches), to provide a stable clock signal for digital integrated circuits, and to stabilize
frequencies for radio transmitters and receivers. The most common type of piezoelectric
resonator used is the quartz crystal, so oscillator circuits incorporating them became known
as crystal oscillators, but other piezoelectric materials including polycrystalline ceramics are
used in similar circuits.
Figure 17: 8 MHz Crystal
VII) IC7805 (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.
20
21. 78XX:-
Figure 18: IC 7805
The Bay Linear LM78XX is integrated linear positive regulator with three
terminals. The LM78XX offer several fixed output voltages making them useful in wide
range of applications. When used as a zener diode/resistor combination replacement,
the LM78XX usually results in an effective output impedance improvement of two
orders of magnitude, lower quiescent current. The LM78XX is available in the TO-252,
TO-220 & TO-263packages,
Features:-
Output Current of 1.5A
Output Voltage Tolerance of 5%
Internal thermal overload protection
Internal Short-Circuit Limited
Output Voltage 5.0V, 6V, 8V, 9V, 10V, 12V, 15V, 18V, 24V.
Regulated Power Supply:
The power supplies are designed to convert high voltage AC mains electricity to
a suitable low voltage supply for electronic 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 DC power supply which maintains the output voltage constant
irrespective of AC mains fluctuations or load variations is known as “Regulated D.C
Power Supply”
For example a 5V regulated power supply system as shown in the next page.
21
22. Figure 19: Components of a typical linear power supply
VIII) 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 other 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
22
23. 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.
Figure 20: 230 AC to 9V AC Step down transformer.
Turns ratio = Vp/ VS = Np/NS.
Power Out= Power In
VS X IS=VP X IP
Vp = primary (input) voltage
Np = number of turns on primary coil
Ip = primary (input) current
IX) Resistors:
A resistor is a device which opposes current in a dc (direct current) circuit; a
measure of this opposition is called resistance, measured in ohms…. Ohm’s Law, the
relationship between voltage, current, and resistance, states that current is directly
proportional to voltage and inversely proportional to resistance in a circuit.
23
24. Figure 21: Resistors
Generally for microcontroller for port P0 whatever we give the input it may be either 1
or 0 the output will be 0 itself because the port P0 will be internally connected to the
ground in order to eliminate this we connect Pull-up resistors in order to overcome
this now in this they are initially connected to the Vcc so that what the input will be the
same will be the output.
X) Capacitors:
Capacitors are in our project for Power Supply, when the AC voltage is initially
given to the bridge circuit in order to convert the AC to DC voltage. As soon as it gets
converted to DC voltage we will not get the pure DC because there will be spikes of
AC voltage. In order to reduce this, we use 1000uf/25v, again we will use the 10uf in
order to reduce the noise that is generated in circuit i.e. thermal noise.
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.
Figure 22: Capacitor
24
25. (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 DC (due to low resistance to
DC)
(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.
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.
XI) LED:-
The light emitting diode (LED) is commonly used as an indicator. It can show
when the power is on, act as a warning indicator, or be part of trendy jewelry etc. It
needs to be fed from a DC supply, with the anode positive and the cathode negative, as
shown in the diagram.
25
26. To calculate the value of the series resistor we need to know the diode forward
voltage and current and its connections. The necessary data can be obtained from a
catalogue or data book. In our example it is 2 volts and 20mA (0.02 amps). The
cathode lead is the one nearest a "flat" on the body. Since the voltage across the diode
is 2 volts and the battery voltage is 12 volts, then the voltage across the resistors 12-2
= 10 volts. The diode is in series with the resistor, so the current through then both is
the same, 0.02 amps.
We now know the voltage across, and the current through the resistor. From Ohm's Law
we can now calculate the value of the resistor.
Resistance = Volts divided by Amps = V/I = 10/0.02 =500 ohms.
Since this is not a standard value we can use a 470 or 560 ohmresistor as this application
is not.
xiii) Liquid Crystal Display (LCD):-
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 polarizers 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 polarizers 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.
26
27. The LCD’s 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. Changing the display size or the layout size is relatively
simple which makes the LCD’s more customer friendly.
Figure 23: A 20x4 LCD
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.
27
28. Chapter 5
Software Design
Another important section in this project is the program code. It can’t be
possible without writing a code to interface all the major components like Micro
controller, RFID cards and LCD.
The flow chart for easy understanding is given below.
5.1 Flow chart:
Start
Micro Controller Initialize
Entered
Person
Invalid User
Return for
next vote
Valid user
Permitted to give his
vote
Initiate
buzzzer
Yes
Security key
for Result
Yes
Show Result in the display
Reset key for
fresh voting
End
Figure 24: Flow chart of Electronic voting using RFID
30. disp_cstr(1,0," PUT YOUR CARD ");
}
else
key_ok=1;
}
else if(!strcmp(recv_buf,p2))
{
disp_cstr(1,0," A.ARUN KUMAR ");
a++;
if(a>1)
{
disp_cstr(1,0," DO NOT CHEAT ");
PORTB.0=1;
delay_ms(2000);
PORTB.0=0;
key_ok=0;
disp_cstr(1,0," PUT YOUR CARD ");
}
else
key_ok=1;
}
else if(!strcmp(recv_buf,p3))
{
disp_cstr(1,0," RAJASHEKAR REDDY ");
r++;
if(r>1)
{
disp_cstr(1,0," DO NOT CHEAT ");
PORTB.0=1;
delay_ms(2000);
PORTB.0=0;
key_ok=0;
disp_cstr(1,0," PUT YOUR CARD ");
}
else
key_ok=1;
}
else if(!strcmp(recv_buf,p4))
{
disp_cstr(1,0," CH.BHARATH NAIDU ");
b++;
if(b>1)
{
disp_cstr(1,0," DO NOT CHEAT ");
PORTB.0=1;
delay_ms(2000);
PORTB.0=0;
key_ok=1;
39
31. disp_cstr(1,0," PUT YOUR CARD ");
}
else
key_ok=1;
}
else
{
key_ok=0;
disp_cstr(1,0," U R NOT AUTHORISED");
PORTB.0=1;
delay_ms(5000);
disp_cstr(1,0," PUT YOUR CARD ");
PORTB.0=0;
}
while(key_ok)
{
if(!PINA.0)
{
delay_ms(500);
while(!PINA.0);
TDP++;
key_ok=0;
disp_cstr(1,0," PUT YOUR CARD ");
}
else if(!PINA.1)
{
delay_ms(500);
while(!PINA.1);
BJP++;
key_ok=0;
disp_cstr(1,0," PUT YOUR CARD ");
}
else if(!PINA.2)
{
delay_ms(500);
while(!PINA.2);
LOK++;
key_ok=0;
disp_cstr(1,0," PUT YOUR CARD ");
}
else if(!PINA.3)
{
delay_ms(500);
while(!PINA.3);
CPI++;
key_ok=0;
disp_cstr(1,0," PUT YOUR CARD ");
}
}
}
31
32. if(!PINA.4)
{
disp_cstr(0,0,"TDP= BJP= ");
disp_cstr(1,0,"LOK= CPI= ");
set_LCD_cur(0,4);
if(TDP==0) wr_disp('0');
else send_math(TDP);
set_LCD_cur(0,14);
if(BJP==0) wr_disp('0');
else send_math(BJP);
set_LCD_cur(1,4);
if(LOK==0) wr_disp('0');
else send_math(LOK);
set_LCD_cur(1,14);
if(CPI==0) wr_disp('0');
else send_math(CPI);
delay_ms(5000);
disp_cstr(0,0," ");
if(TDP>BJP&&TDP>LOK&&TDP>CPI)
disp_cstr(1,0," TDP HAS WON ");
else if(BJP>TDP&&BJP>LOK&&BJP>CPI)
disp_cstr(1,0," BJP HAS WON ");
else if(LOK>BJP&&LOK>TDP&&LOK>CPI)
disp_cstr(1,0," LOKSATHA HAS WON ");
else if(CPI>BJP&&CPI>LOK&&CPI>TDP)
disp_cstr(1,0," CPI HAS WON ");
else
disp_cstr(1,0," TIE ");
}
}
}
32
33. Chapter 6
Testing and Results
Result Analysis:
We started our project by making power supply. That is easy for me but when
we turn toward the main circuit, there are many problems and issues related to it, which
are we faced, like component selection, which components is better than other and its
feature and cost wise also, then refer the data books and other materials related to its.
We had issues with better or correct result, which we desired. And also the software
problem.
We also had some soldering issues which were resolved using continuity
checks performed on the hardware
We started testing the circuit from the power supply. There we got over first
trouble. After getting 9V from the transformer it was not converted to 5V and the circuit
received 9V.
As the solder was shorted IC 7805 got burnt. So we replaced the
IC7805.also the circuit part around the IC7805 were completely damaged with the help
of the solder we made the necessary paths.
It would be a problem to identify individual RFID cards unless it is placed
before the RFID reader module and LCD is a must in this process.
It will be helpful for small elections like electing a class representative or for
any situation to vote for few choices among few members.
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34. Evolution
Applications:
o It can be used in taking group decisions where voting is confidential.
o It can be used in companies, industries, Schools, Colleges or any Private
or Government Sectors.
o It can be used for different purposes not only for voting system.
Advantages:
o Tampering is not possible.
o Good security can be achieved by using this technology.
o Process for voting would be very easy.
Disadvantages:
o If Micro controller is damaged, then it’ll be difficult to re install,
program and solder the part.
o There must be scrutiny of the persons because RFID card is transferable
and there can be a chance for a person to come with other person’s card.
o Extreme care must be taken to protect the entire circuit/PCB from
getting damaged.
Future scope:
o A timer could be included, which could automatically end the voting
after specified duration of time.
o Biometric verification of voters, so that automatically it can be insured
that one person is voting only once.
o It can be made more interactive by adding sound effect (speech) to it.
o EEPROM can be used to store the data permanently.
o If we make more than one EVM, each to be used at all different
locations and the final result is the addition of result of all, we could
think of connecting them to communicate with each other and final
result can be shown on one of the LCD.
o Touch can be implemented in place of switches.
34
35. Conclusion
With the knowledge in Electronics we could make an application like “Electronic
voting machine using RFID” Our project installation is somewhat difficult but once
installed it is easy to work with it. The circuit can easily connect to the output port of
LCD and can be used to see which person is going to the voting machine.
We completed our mini project with desired output. The desired output was
obtained by a microcontroller which is followed by RFID Module. The circuit was
analyzed and verified with different inputs successfully.
Final apparatus of our project
35
36. Bibliography
[1] International Journal of Information and Electronics Engineering, Vol. 3, No. 2,
March 2013.
[2] E. Proebstel, S. Riddle, F. Hsu, J. Cummins, F. Oakley, T. Stanionis, and M.
Bishop, “An Analysis of the Hart Intercivic DAU eSlate,” in Proc. Of Usenix/Accurate
Electronic Voting Technology Workshop, 2007.
[3] For Data Sheet of Micro controller,
http://www.atmel.com/Images/doc2466.pdf
[4] klaus Finkenzeller, ‘RFID Handbook for Fundamentals and Applications in
contactless Smart Cards, Radio Frequency identification and Near-Field
Communication’ 3rd
Edition, [WILEY].
[5] For RFID Reader module (328140),
PARALLAX, Inc. www.parallax.com
[6] For most of the images and information,
www.google.com
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