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1.INTRODUCTION
The present inventions relates to an electronic locking system that can
be easily installed and achieves a security level not possible in traditional mechanical locking
systems. It is well known facts that mechanical locks, such the pin tumbler block, dead bolt
and side bar lock have security disadvantages in that these locks can be opened by
unauthorized persons who have some expertise in this field.
In an Electronic card lock system, a lock, a card slot for said lock, an electronic card
made of insulating material injected into the mechanism. This drives the particular
application. For particular application certain card has to be used. This project is a simple
version of card lock system where the advanced versions of this may lead to vast applications
in modern technological world.
The important components in this project are Infra red Leds, Photo Diodes and
relays. Where optical sensors make sensing of rays. Where octal buffers and relay drivers are
also used to store some data and to drive relays respectively. Here we used leds as the
output agents where the output observed by various ordinary leds.
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2.CIRCUIT DIAGRAM
Figure 2.1: Circuit diagram
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3.LIST OF COMPONENTS
NAME OF COMPONENT QUANTITY
Resistors:
100-ohm : 5 10k-ohm : 3Capacitors:
1000uf : 1 470uf : 1Diodes:
IN4007 : 3 Photo diodes : 4LEDs:
Red led [1-3] : 3 IR Leds : 3TRANSISTORs:
BC548 : 1ICs: 74LS244 : 1 ULN2003 : 1 7805 : 1 UM66 : 1Miscellaneous:
Ic base 20 pin : 1 Ic base 16 pin : 1 Relays (12v DC) : 3Push to on switch:
Transformer (12-0-12v) : 1 Insulating cards : 3
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4.COMPONENTS DESCRIPTION
4.1 RESISTOR:
The resistor is the most common and well-known of the passive electrical
components. A resistor resists or limits the flow of electric current in a circuit. There are
many uses for resistors: they are used to drop voltage, limit current, attenuate signals, act as
heaters, act as fuses, furnish electrical loads and divide voltages.
Symbol of resistor:
Figure 4.1:symbol of resistor
Units of resistor: ohm
Resistors limit current. In a typical application, a resistor is connected in series with an LED:Types of resistors:
Figure 4.2:Types of Resistors
Fixed resistors: A fixed resistor is one in which the value of its resistance cannot change.
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Variable resistors: A variable resistor is a resistor whose value can be adjusted by turning ashaft or sliding a control. They are also called potentiometers or rheostats and allow the
resistance of the device to be altered by hand.
Non-Linear resistors: A non-linear resistor is a resistor that has resistances that varysignificantly with applied voltage, temperature or light.
Types of non-linear resistors are varistors, thermistors and photo resistors.Color coding of resistors:
Resistors are coded to indicate the resistance value and tolerance. Carbon-composition and
carbon film resistors are too small to have the resistance value printed on their housings.
Therefore, bands of color are used to represent the resistance value.
Figure 4.3: Color coding of Resistors
The first and second band represents the numerical value of the resistor, and the color
of the third band specifies the power-of-ten multiplier. The color bands are always read from
left to right starting with the side that has a band closer to the edge.
Tolerance:
For carbon-composition and carbon film resistors, the common tolerances are 5%,
10%, and 20%, indicating that the actual value of the resistor can vary from the nominal
value by 5%, 10% and 20%. If the band is gold, it specifies a 5% tolerance; silver
specifies a 10% tolerance; if no band is present, the tolerance is 20%. Note that the color-
code system for capacitors is very similar to that of resistors except there is a fifth band
representing the temperature coefficient. This band is the first one closest to one end of the
capacitor. The other four fall into the same order as mentioned for resistors. In this case, the
second, third, and fourth bands are used to determine the capacitance. The fifth band
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represents the tolerance of the capacitor. The table below shows the color code and their
associated value:
Resistor Symbols
Resistor schematic symbols of electrical & electronic circuit diagram - resistor,
potentiometer, and variable resistor.
Table of resistor symbols:
Resistor (IEEE)Resistor reduces the current flow.
Resistor (IEC)
Potentiometer (IEEE)
Adjustable resistor - has 3 terminals.
Potentiometer (IEC)
Variable Resistor /
Rheostat (IEEE) Adjustable resistor - has 2 terminals.
Variable Resistor /
Rheostat (IEC)
Trimmer Resistor Preset resistor
ThermistorThermal resistor - change resistance when
temperature changes
Photo resistor / Light Changes resistance according to light
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dependent resistor
(LDR)
4.2 CAPACITORS:
A capacitor is a passive electronic component that stores energy in the form of an
electrostatic field. In its simplest form, a capacitor consists of two conducting plates
separated by an insulating material called the dielectric. The capacitance is directly
proportional to the surface areas of the plates, and is inversely proportional to the separation
between the plates. Capacitance also depends on the dielectric constant of the substance
separating the plates.
The standard unit of capacitance is the farad, abbreviated.
This is a large unit; more common units are the microfarad, abbreviated F (1 F =10-6
F) and
the picofarad, abbreviated pF (1 pF = 10-12
F).
Capacitors can be fabricated onto integrated circuit (IC) chips. They are
commonly used in conjunction with transistors in dynamic random access memory (DRAM).
The capacitors help maintain the contents of memory. Because of their tiny physical size,
these components have low capacitance. They must be recharged thousands of times per
second or the DRAM will lose its data.
Symbol of capacitor:
Figure 4.4:symbol of capacitor
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Characteristics: In its most elementary state a capacitor consists of two metal plates
separated by a certain distance d, in between the plates lies a dielectric material with
dielectric constant = o, where o is the dielectric of air.The dielectric material allows for
charge to accumulate between the capacitor plates. Air (Actually vacuum) has the lowest
dielectric value ofo = 8.854 * 10-12
Farads/meter where the Farad is the unit for
capacitance. All other materials have higher dielectric values, since they are higher in density
and can therefore accumulate more charge.
Capacitance is defined to be the amount of charge Q stored in between the two plates
for a potential difference or voltage V existing across the plates. In other words:
The capacitance C is given by C = Q/V (electrical definition)
The Physical meaning of capacitance can be seen by relating it to the physical
characteristics of the two plates, so that, the capacitance is related to the dielectric of the
material in between the plates, the square area of a plate and the distance between the plates
by the formula: C = o A/d
Clearly, the larger the area of the plate the more charge can be accumulated and hence
the larger the capacitance. Also, note that as the distance d increases the Capacitance
decreases since the charge cannot be contained as 'densely' as before. Both definitions of
Capacitance are compatible, although for our purposes we will be referring mostly to the
electrical definition.
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Types of Capacitors:
The simple two-plate capacitor model falls short in representing all capacitors since
we have different types such as: ceramic disc capacitors, electrolytic capacitors, polyester
capacitors, tantalum capacitors and surface mount capacitors. Each type is selected according
to several criteria, essentially: the maximum voltage the capacitor can hold the value of the
dielectric, dimensions and tolerance ratings.
Figure 4.5: Types of Capacitors
Polyester Film Capacitor: Polyester film capacitors are used where cost is a consideration
as they do not offer a high tolerance. Many polyester film capacitors have a tolerance of 5%
or 10%, which is adequate for many applications. They are generally only available as leaded
electronics components.
Electrolytic capacitor: Electrolytic capacitors are a type of capacitor that is polarized. They
are able to offer high capacitance values - typically above 1F, and are most widely used for
low frequency applications - power supplies, decoupling and audio coupling applications as
they have a frequency limit if around 100 kHz.
Surface mount:SMD capacitors are used in vast quantities. After SMD resistors they are the
most widely used type of component. There are many different types of SMD capacitor
ranging from ceramic types, through tantalum varieties to electrolytic and more. Of these, theceramic SMD capacitors are the most widely used.
Ceramic capacitor: The ceramic capacitor is a type of capacitor that is used in many
applications from audio to RF. Values range from a few picofarads to around 0.1
microfarads. Ceramic capacitors are by far the most commonly used type of capacitor being
cheap and reliable and their loss factor is particularly low although this is dependent on the
exact dielectric in use
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Applications of capacitor:
The following is the typical capacitor applications in electronic industries:
DC blocking capacitor: In this application the capacitor blocks the passage of DC current(after completely charged) and yet allows the AC to pass at certain portion of a circuit.
Capacitor as a filter: Capacitors are the main elements of filters. There are several types offilters that are used in electronic circuits, such as LPF (Low Pass Filter), HPF (high Pass
Filter), BPF (Band Pass Filter), etc.Since the reactance of the capacitor is inversely related
to the frequency, therefore it can be used to increase or decrease the impedance of the circuit
at certain frequencies and therefore does the filtration job.
Capacitor as a discharge unit: Capacitors used as a charging unit and the release of thecharge (discharge energy) is used for triggering, ignition, and in high scale as a power source.
By Pass capacitor: The reactance of capacitor decreases as the frequency increases.Therefore in certain application it is used in parallel with other components to bypass it at a
specified frequency.
4.3 Diodes:
An electronic device that restricts current flow chiefly to one direction. A diode is a
specialized electronic component with two electrodes called the anode & the cathode. Mostdiodes are made with semiconductor materials such as silicon, germanium, or selenium.
Some diodes are comprised of metal electrodes in a chamber evacuated or filled with a pure
elemental gas at low pressure. Diodes can be used as rectifiers, signal limiters, voltage
regulators, switches, signal modulators, signal mixers, signal demodulators, and oscillators.
Symbol of diode:
Figure 4.6:Symbol of diode
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Types of diodes:
Several types of diodes are available for use in electronics design. Some of the different types
of diodes are:
Figure 4.7:Types of diodes
Light Emitting Diode (LED): It is one of the most popular types of diodes and when this
diode permits the transfer of electric current between the electrodes, light is produced. In
most of the diodes, the light (infrared) cannot be seen as they are at frequencies that do not
permit visibility. When the diode is switched on or forward biased, the electrons recombine
with the holes and release energy in the form of light (electroluminescence).The color of light
depends on the energy gap of semiconductor.
Avalanche Diode: This type of diode operates in the reverse bias, and used avalanche effect
for its operation. The avalanche breakdown takes place across the entire PN junction, when
the voltage drop is constant and is independent of current. Generally, the avalanche diode is
used for photo-detection, wherein high levels of sensitivity can be obtained by the avalanche
process.
Laser Diode: This type of diode is different from the LED type, as it produces coherent light.
These diodes find their application in DVD and CD drives, laser pointers, etc. However, they
are cheaper than other forms of laser generators. Moreover, these laser diodes have limited
life.
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Schottky Diodes: The lower forward voltage drop may be somewhere between 0.15 and 0.4
volts at low currents, as compared to the 0.6 volts for a silicon diode. In order to achieve this
performance, these diodes are constructed differently from normal diodes, with metal to
semiconductor contact. Schottky diodes are used in RF applications, rectifier applications and
clamping diodes.
Zener diode: This type of diode provides a stable reference voltage, thus is a very useful
type and is used in vast quantities. The diode runs in reverse bias, and breaks down on the
arrival of a certain voltage. A stable voltage is produced, if the current through the resistor is
limited. In power supplies, these diodes are widely used to provide a reference voltage.
Photodiode: Photodiodes are used to detect light and feature wide, transparent junctions.
Generally, these diodes operate in reverse bias, wherein even small amounts of current flow,
resulting from the light, can be detected with ease. Photodiodes can also be used to generate
electricity, used as solar cells and even in photometry in the photo diode.
Varicap Diode or Varactor Diode: This type of diode feature a reverse bias placed upon it,
which varies the width of the depletion layer as per the voltage placed across the diode. This
diode acts as a capacitor and capacitor plates are formed by the extent of conduction regions
and the depletion region as the insulating dielectric. By altering the bias on the diode, the
width of the depletion region changes, thereby varying the capacitance.
Rectifier Diode: These diodes are used to rectify alternating power inputs in power supplies.
They can rectify current levels that range from an amp upwards. If low voltage drops are
required, then Schottky diodes can be used, however, generally these diodes are PN junction
diodes.
ZENER DIODE: A silicon semiconductor device used as a voltage regulator because of its
ability to maintain an almost constant voltage with a wide range of currents.
Example: Circuit symbol:
a = anode, k = cathode
Figure 4.8:zener diode
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Zener diodes are used to maintain a fixed voltage. They are designed to 'breakdown' in a reliable and
non-destructive way so that they can be used in reverseto maintain a fixed voltage across their
terminals. The diagram shows how they are connected, with a resistor in series to limit the current.
Zener diodes can be distinguished from ordinary diodes by their code and breakdown voltage which
are printed on them. Zener diode codes begin BZX... or BZY... Their breakdown voltage is printed
with V in place of a decimal point, so 4V7 means 4.7V for
example.
Zener diodes are rated by their breakdown voltage and
maximum power:
The minimum voltage available is 2.4V. Power ratings of 400mW and 1.3W are common.
Diode operation:
Forward bias: In forward bias operation, the diode will not conduct significant
current until the voltage reaches about 0.7V. After that point large increases in current cause
little change in voltage.
Reverse bias: In reverse bias operation, the diode will not conduct significant current
until some breakdown threshold voltage which is typically quite large (e.g. 200V). This
voltage must be somewhat greater than the peak input voltage (PIV) rating of the diode.
(Device dependent)
Figure 4.9:Diode Characteristics
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4.4 PHOTO DIODE:
A photodiode is a type ofphoto detector capable of converting light into either current
or voltage, depending upon the mode of operation. The common, traditional solar cell used to
generate electric solar power is a large area photodiode.
Photodiodes are similar to regular semiconductor diodes except that they may be
either exposed (to detect vacuum UV or X-rays) or packaged with a window or optical fiber
connection to allow light to reach the sensitive part of the device. Many diodes designed for
use specifically as a photodiode use a PIN junction rather than a p-n junction, to increase the
speed of response. A photodiode is designed to operate in reverse bias
Symbol of Photo Diode:
Figure 4.10:Symbol of photo diode
Principle of operation:
A photodiode is a p-n junction or PIN structure. When a photon of sufficient energy
strikes the diode, it excites an electron, thereby creating a free electron (and a positively
charged electron hole). This mechanism is also known as the inner photoelectric effect. If the
absorption occurs in the junction's depletion region, or one diffusion length away from it,
these carriers are swept from the junction by the built-in field of the depletion region. Thus
holes move toward the anode, and electrons toward the cathode, and a photocurrent is
produced. This photocurrent is the sum of both the dark current (without light) and the light
current, so the dark current must be minimized to enhance the sensitivity of the device.
http://en.wikipedia.org/wiki/Photodetectorhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Solar_cellhttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Vacuum_UVhttp://en.wikipedia.org/wiki/X-rayshttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/PIN_diodehttp://en.wikipedia.org/wiki/P-n_junctionhttp://en.wikipedia.org/wiki/Reverse_biashttp://en.wikipedia.org/wiki/P-n_junctionhttp://en.wikipedia.org/wiki/PIN_diodehttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Free_electronhttp://en.wikipedia.org/wiki/Photoelectric_effecthttp://en.wikipedia.org/wiki/Depletion_regionhttp://en.wikipedia.org/wiki/Anodehttp://en.wikipedia.org/wiki/Cathodehttp://en.wikipedia.org/wiki/Photocurrenthttp://en.wikipedia.org/wiki/Photocurrenthttp://en.wikipedia.org/wiki/Cathodehttp://en.wikipedia.org/wiki/Anodehttp://en.wikipedia.org/wiki/Depletion_regionhttp://en.wikipedia.org/wiki/Photoelectric_effecthttp://en.wikipedia.org/wiki/Free_electronhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/PIN_diodehttp://en.wikipedia.org/wiki/P-n_junctionhttp://en.wikipedia.org/wiki/Reverse_biashttp://en.wikipedia.org/wiki/P-n_junctionhttp://en.wikipedia.org/wiki/PIN_diodehttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/X-rayshttp://en.wikipedia.org/wiki/Vacuum_UVhttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Solar_cellhttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Photodetector7/30/2019 Electronic Cardlock System
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Figure 4.11: Characteristics of Photo diode
Photovoltaic mode:
When used in zero bias or out of the photovoltaic mode, the flow of photocurrent
device is restricted and a voltage builds up. This mode exploits the photovoltaic effect, which
is the basis for solar cellsa traditional solar cell is just a large area photodiode.
Photoconductive mode:
In this mode the diode is often reverse biased ,dramatically reducing the response time
at the expense of increased noise. This increases the width of the depletion layer, which
decreases the junction's capacitance resulting in faster response times. The reverse bias
induces only a small amount of current along its direction while the photocurrent remains
virtually the same. For a given spectral distribution, the photocurrent is linearly proportional
to the luminance.
Applications:
1. P-N photodiodes are used in similar applications to other photo detectors, such asphotoconductors, charge-coupled devices, and photomultiplier tubes. They may be used to
generate an output which is dependent upon the illumination (analog; for measurement and
the like), or to change the state of circuitry (digital; either for control and switching, or digital
signal processing).
http://en.wikipedia.org/wiki/Bias_%28electrical_engineering%29http://en.wikipedia.org/wiki/Photovoltaic_effecthttp://en.wikipedia.org/wiki/Solar_cellhttp://en.wikipedia.org/wiki/P-n_junction#Reverse_biashttp://en.wikipedia.org/wiki/Capacitancehttp://en.wikipedia.org/wiki/Illuminancehttp://en.wikipedia.org/wiki/Photodetectorhttp://en.wikipedia.org/wiki/Photoconductorhttp://en.wikipedia.org/wiki/Charge-coupled_devicehttp://en.wikipedia.org/wiki/Photomultiplierhttp://en.wikipedia.org/wiki/Photomultiplierhttp://en.wikipedia.org/wiki/Charge-coupled_devicehttp://en.wikipedia.org/wiki/Photoconductorhttp://en.wikipedia.org/wiki/Photodetectorhttp://en.wikipedia.org/wiki/Illuminancehttp://en.wikipedia.org/wiki/Capacitancehttp://en.wikipedia.org/wiki/P-n_junction#Reverse_biashttp://en.wikipedia.org/wiki/Solar_cellhttp://en.wikipedia.org/wiki/Photovoltaic_effecthttp://en.wikipedia.org/wiki/Bias_%28electrical_engineering%297/30/2019 Electronic Cardlock System
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2. Photodiodes are used in consumer electronics devices such as compact disc players, smokedetectors, and the receivers for infrared remote control devices used to control equipment
from televisions to air conditioners. For many applications either photodiodes or
photoconductors may be used. Either type of photo sensor may be used for light
measurement, as in camera light meters, or to respond to light levels, as in switching on street
lighting after dark.
3. Photo sensors of all types may be used to respond to incident light, or to a source of lightwhich is part of the same circuit or system. A photodiode is often combined into a single
component with an emitter of light, usually a light-emitting diode (LED), either to detect the
presence of a mechanical obstruction to the beam (slotted optical switch), or to couple two
digital or analog circuits while maintaining extremely high electrical isolation between them,
often for safety (optocoupler).
4. Photodiodes are often used for accurate measurement of light intensity in science andindustry. They generally have a more linear response than photoconductors.
5. They are also widely used in various medical applications, such as detectors for computedtomography (coupled with scintillators), instruments to analyze samples (immunoassay), and
pulse oximeters.
6. PIN diodes are much faster and more sensitive than p-n junction diodes, and hence are oftenused for optical communications and in lighting regulation.
4.5 Light Emitting Diodes (LEDs):
Circuit symbol:
Figure 4.12:Symbol of LED
Parts in LED:
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Figure 4.13: parts of LED
Function: LEDs emit light when an electric current passes through them.
PIN DIAGRAM:
Figure 4.14:Pin diagram of LED
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LED Specifications:
These are infrared LEDs; the light output is not visible by our eyes. They can
be used as replacement LEDs for remote controls, night vision for camcorders, invisible
beam sensors, etc.
Size (mm) 5mm
Lens Color Light Blue
Peak wavelength up 940nm
Continuous Forward Current IF 20 am
Typical Voltage (V) 1.3
Peak Forward Current IFP 1.0 A
Reverse Voltage VR 5 V
Operating Temperature Top -40 ~ +85
Storage Temperature TSgt -40 ~ +85
Soldering Temperature Ts l 260
Connecting and soldering:
LEDs must be connected the correct way round, the diagram may be
labeled a or + for anode and k or - for cathode. The cathode is the short lead
and there may be a slight flat on the body of round LEDs. If you can see inside
the LED the cathode is the larger electrode. LEDs can be damaged by heat when soldering,
but the risk is small unless you are very slow. No special precautions are needed for soldering
most LEDs. Figure 4.15:testing an LED
Testing an LED:
Never connect an LED directly to a battery or power supply! It will be
destroyed almost instantly because too much current will pass through and burn
it out.LEDs must have a resistor in series to limit the current to a safe value, for
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quick testing purposes a 1k resistor is suitable for most LEDs if your supply
voltage is 12V or less. Remember to connect the LED the correct way round!
Colors of LEDs:
LEDs are available in red, orange, amber, yellow, green, blue and white. Blue and
white LEDs are much more expensive than the other colors.
The colour of an LED is determined by the semiconductor material, not by the
coloring of the 'package' (the plastic body). LEDs of all colors are available in uncolored
packages which may be diffused (milky) or clear (often described as 'water clear'). The
colored packages are also available as diffused (the standard type) or transparent.
Tri-colour LEDs:
The most popular type of tri-colour LED has a red and a green LED
combined in one package with three leads. They are called tri-colour because
mixed red and green light appears to be yellow and this is produced when both the
red and green LEDs are on. The diagram shows the construction of a tri-colour LED. Note
the different lengths of the three leads. The centre lead (k) is the common cathode for both
LEDs, the outer leads (a1 and a2) are the anodes to the LEDs allowing each one to be lit
separately, or both together to give the third colour.
Bi-colour LEDs:
A bi-colour LED has two LEDs wired in 'inverse parallel' (one
forwards, one backwards) combined in one package with two leads.
Only one of the LEDs can be lit at one time and they are less useful
than the tri-colour LEDs described above.
As well as a variety of colors, sizes and shapes, LEDs also vary in their viewing
angle. This tells you how much the beam of light spreads out. Standard LEDs have a viewing
angle of 60 but others have a narrow beam of 30 or less.
Connecting LEDs in series:
If you wish to have several LEDs on at the same time it may be possible to connect
them in series. This prolongs battery life by lighting several LEDs with the same current as
just one LED. All the LEDs connected in series pass the same current so it is best if they
are all the same type. The power supply must have sufficient voltage to provide about 2V for
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each LED (4V for blue and white) plus at least another 2V for the resistor. To work out a
value for the resistor you must add up all the LED voltages and use this for VL.
Calculating an LED resistor value:
An LED must have a resistor connected in series to limit the current through the LED,
otherwise it will burn out almost instantly.
The resistor value, R is given by:
R = (VS - VL) / I
VS=supply-voltage
VL = LED voltage (usually 2V, but 4V for blue
and white LEDs) I = LED current (e.g.
10mA = 0.01A,
or 20mA = 0.02A)
Make sure the LED current you choose is less than the maximum permitted
and convert the current to amps (A) so the calculation will give the resistor value in
ohms.To convert mA to A divide the current in mA by 1000 because 1mA = 0.001A.
If the calculated value is not available choose the nearest standard resistor value
which is greater, so that the current will be a little less than you chose. In fact you may wish
to choose a greater resistor value to reduce the current (to increase battery life for example)
but this will make the LED less bright.
Avoid connecting LEDs in parallel!:
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Connecting several LEDs in parallel with just one resistor shared between them is
generally not a good idea. If the LEDs require slightly different voltages only the lowest
voltage LED will light and it may be destroyed by the larger current flowing through it. If
LEDs are in parallel each one should have its own resistor.
Reading a table of technical data for LEDs:
Suppliers' catalogues usually include tables of technical data for components such as
LEDs. These tables contain a good deal of useful information in a compact form but they can
be difficult to understand if you are not familiar with the abbreviations used.
The table below shows typical technical data for some 5mm diameter round LEDs
with diffused packages (plastic bodies). Only three columns are important and these are
shown in bold. Please see below for explanations of the quantities.
Type ColourIF
max.
VF
typ.
VF
max.
VR
max.
Luminous
intensity
Viewing
angleWavelength
Standard Red 30mA 1.7V 2.1V 5V5mcd @
10mA60 660nm
StandardBright
red30mA 2.0V 2.5V 5V
80mcd @
10mA60 625nm
Standard Yellow 30mA 2.1V 2.5V 5V32mcd @
10mA60 590nm
Standard Green 25mA 2.2V 2.5V 5V32mcd @
10mA60 565nm
High
intensityBlue 30mA 4.5V 5.5V 5V
60mcd @
20mA50 430nm
Super
brightRed 30mA 2.5V 5V
500mcd @
20mA60 660nm
4.6 INFRA RED LED:
An IR LED, also known as IR transmitter, is a special purpose LED that transmits
infrared rays in the range of 760 nm wavelength. Such LEDs are usually made of gallium
arsenide or aluminum gallium arsenide. They, along with IR receivers, are commonly used as
sensors.
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Symbol of IR LED:
Figure 4.16:Symbol of IR LED
The appearance is same as a common LED. Since the human eye cannot see the
infrared radiations, it is not possible for a person to identify whether the IR LED is working
or not, unlike a common LED. To overcome this problem, the camera on a cell phone can be
used. The camera can show us the IR rays being emanated from the IR LED in a circuit.
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4.7 TRANSISTOR:
Bipolar junction transistor (BJI) or simply transistor was invented in 1950 by Schockely. It is the
invention of the junction transistor that has brought the revolution change in the field of electronics.
The name transistor was coined from the words transfer resistor. Because this semiconductor device
offers low resistance to the flow of current in one portion (Emitter-Base junction) while high
resistance in the other portion (collection-base junction) of the device. It means that transistor
transforms current flow from low resistance path to the high resistance path.
FORMATION OF TRANSISTORS:
A transistor is basically a silicon or germanium crystal containing three separate regions. It is formed
by the sandwich of a thin layer of one type (either N type or p type) semiconductor material between
two layers of other semiconductor material. So transistor may be regarded as two back junctions in a
single piece of semi conductor.
The two junctions give rise to three regions. The middle region is called base and the outer two
regions are called as Emitter and collector. Even though outer regions are of the same type theirfunction cannot be interchanged. Because, the two regions have different physical & electrical
properties. Three terminals were taken from three regions, namely Emitter Base & Collector. The PN
junction or Emitter junction and the PN junction between Base and collectors called Collector Base
junction or simply collector junction.
So transistor is a three layers, two junction, and three terminal semiconductor device.
EMITTER (E):
It is that region of the transistor which emits majority charge carriers into base region. Physical area of emitter is less than collector but more the base region. Its doping concentration is more than both base and collector.
BASE (B):
It is the middle region of the transistor.
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It is very thin and lightly doped as compared to either emitter or collector.
COLLECTOR (C):
It is that region of the transistor which collects the majority charge carriers emitted bythe emitter through the base region
Its doping concentration is greater than base region & less than emitter region. In general collector region is made physically larger than emitter and base to dissipate
much heat generated
BC548:
BC548 is general purpose silicon, NPN, bipolar junction transistor. It is used for
amplification and switching purposes. The current gain may vary between 110 and 800. The
maximum DC current gain is 800.
Its equivalent transistors are 2N3904 and 2SC1815. These equivalent transistors however
have different lead assignments. The variants of BC548 are 548A, 548B and 548C which
vary in range of current gain and other characteristics.
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 amplification applications, the
transistor is biased such that it is partly on for all input conditions. The input signal at base is
amplified and taken at the emitter. BC548 is used in common emitter configuration for
amplifiers. The voltage divider is the commonly used biasing mode. For switching
applications, transistor is biased so that it remains fully on if there is a signal at its base. In
the absence of base signal, it gets completely off.
Figure 4.17:Pin diagram of BC548.
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Advantages:
The key advantages that have allowed transistors to replace their vacuum tube predecessors
in most applications are
Small size and minimal weight, allowing the development of miniaturized electronicdevices.
Highly automated manufacturing processes, resulting in low per-unit cost. Lower possible operating voltages, making transistors suitable for small, battery-
powered applications.
No warm-up period for cathode heaters required after power application. Lower power dissipation and generally greater energy efficiency. Higher reliability and greater physical ruggedness. Extremely long life. Some transistorized devices have been in service for more than
50 years.
Complementary devices available, facilitating the design of complementary-symmetry circuits, something not possible with vacuum tubes.
Insensitivity to mechanical shock and vibration, thus avoiding the problemof microphones in audio applications.
Limitations:
High power, high frequency operation, such as that used in over-the-air televisionbroadcasting, is better achieved in electron tubes due to improved electron mobility in
a vacuum.
Silicon transistors do not operate at voltages higher than about1,000 volts (SiC devices can be operated as high as 3,000 volts). In contrast, electron
tubes have been developed that can be operated at tens of thousands of volts.
Silicon transistors are much more vulnerable than electron tubes to an electromagneticpulse generated by a high-altitude nuclear explosion.
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4.8 RELAY:
A relay is usually an electromechanical device that is actuated by an electrical
current. The current flowing in one circuit causes the opening or closing of another circuit.
Relays are like remote control switches and are used in many applications because of their
relative simplicity, long life, and proven high reliability.
Relays are used in a wide variety of applications throughout industry, such as in
telephone exchanges, digital computers and automation systems. Highly sophisticated relays
are utilized to protect electric power systems against trouble and power blackouts as well as
to regulate and control the generation and distribution of power.
In the home, relays are used in refrigerators, washing machines and dishwashers, and
heating and air-conditioning controls. Although relays are generally associated with electrical
circuitry, there are many other types, such as pneumatic and hydraulic. Input may be
electrical and output directly mechanical, or vice versa.
Relay Design:
There are only four main parts in a relay. They are
Electromagnet Movable Armature Switch point contacts Spring
The figures given below show the actual design of a simple relay.
Relay Construction:
It is an electro-magnetic relay with a wire coil, surrounded by an iron core. A path of
very low reluctance for the magnetic flux is provided for the movable armature and also the
switch point contacts. The movable armature is connected to the yoke which is mechanically
connected to the switch point contacts. These parts are safely held with the help of a spring.
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The spring is used so as to produce an air gap in the circuit when the relay becomes de-
energized.
Figure 4.18:Relay construction
Working of Relay:
The working of a relay can be better understood by explaining the following diagram
given below.
Figure 4.19: working of relay
The diagram shows an inner section diagram of a relay. An iron core is surrounded by
a control coil. As shown, the power source is given to the electromagnet through a control
switch and through contacts to the load. When current starts flowing through the control coil,
the electromagnet starts energizing and thus intensifies the magnetic field. Thus the upper
contact arm starts to be attracted to the lower fixed arm and thus closes the contacts causing a
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short circuit for the power to the load. On the other hand, if the relay was already de-
energized when the contacts were closed, then the contact move oppositely and make an open
circuit.
As soon as the coil current is off, the movable armature will be returned by a force
back to its initial position. This force will be almost equal to half the strength of the magnetic
force. This force is mainly provided by two factors. They are the spring and also gravity.
Relays are mainly made for two basic operations. One is low voltage application and
the other is high voltage. For low voltage applications, more preference will be given to
reduce the noise of the whole circuit. For high voltage applications, they are mainly designed
to reduce a phenomenon called arcing.
Relay Basics:
The basics for all the relays are the same. Take a look at a 4pin relay shown below.
There are two colors shown. The green color represents the control circuit and the red color
represents the load circuit. A small control coil is connected onto the control circuit. A switch
is connected to the load. This switch is controlled by the coil in the control circuit. Now let us
take the different steps that occur in a relay. Relay operation:
Energized Relay (ON):
As shown in the circuit, the current flowing through the coils represented by pins 1
and 3 causes a magnetic field to be aroused. This magnetic field causes the closing of the pins
2 and 4. Thus the switch plays an important role in the relay working. As it is a part of the
load circuit, it is used to control an electrical circuit that is connected to it. Thus, when the
relay in energized the current flow will be through the pins 2 and 4.
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Energized Relay (ON)
DeEnergized Relay (OFF):
As soon as the current flow stops through pins 1 and 3, the switch opens and thus the
open circuit prevents the current flow through pins 2 and 4. Thus the relay becomes de-
energized and thus in off position. De-Energized Relay (OFF)
In simple, when a voltage is applied to pin 1, the electromagnet activates, causing a
magnetic field to be developed, which goes on to close the pins 2 and 4 causing a closed
circuit. When there is no voltage on pin 1, there will be no electromagnetic force and thus no
magnetic field. Thus the switches remain open.
Relay Applications:
Relays are used to realize logic functions. They play a very important role in providing
safety critical logic.
Relays are used to provide time delay functions. They are used to time the delay open anddelay close of contacts.
Relays are used to control high voltage circuits with the help of low voltage signals. Similarlythey are used to control high current circuits with the help of low current signals.
They are also used as protective relays. By this function all the faults during transmission andreception can be detected and isolated.
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Advantages of Relays:
The complete electrical isolation improves safety by ensuring that high voltages and currentscannot appear where they should not be.
It is easy to tell when a relay is operating - you can hear a click as the relay switches on andoff and you can sometimes see the contacts moving.
Disadvantages of Relays:
Being mechanical though, relays do have some disadvantages over other methods of
electrical isolation:
Their parts can wear out as the switch contacts become dirty - high voltages and currentscause sparks between the contacts.
They cannot be switched on and off at high speeds because they have a slow response and theswitch contacts will rapidly wear out due to the sparking.
SPEAKER:
In tis circuit we used 8ohms,0.5w speaker to produce the desired out put melody at the out
put side. the external view of the speaker is
Figure 4.20: Speaker
4.9INTEGRATED CIRCUITS:4.9.1 IC 7805:
7805 is a voltage regulator integrated circuit. It is a member of 78xx series of
fixed linear voltage regulator ICs. The voltage source in a circuit may have fluctuations
and would not give the fixed voltage output. The voltage regulator IC maintains the
output voltage at a constant value. The xx in 78xx indicates the fixed output voltage it is
designed to provide. 7805 provides +5V regulated power supply. Capacitors of suitable
values can be connected at input and output pins depending upon the respective voltage
levels.
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Figure 4.21:PIN DIAGRAM FOR 7805
Pin Description:
Pin No Function Name
1 Input voltage (5V-18V) Input
2 Ground (0V) Ground
3 Regulated output; 5V (4.8V-5.2V) Output
4.9.2 IC 74LS244:
General Description:
These buffers/line drivers are designed to improve both the performance and PC board
density of 3-STATE buffers/drivers employed as memory-address drivers, clock drivers, and
bus-oriented transmitters/receivers.
Featuring 400mV of hysteresis at each low current PNP data line input, they provide
improved noise rejection and high fan-out outputs and can be used to drive terminated lines
down to133
Figure 4.22:IC 74LS244
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Features:
3-STATE outputs drive bus lines directly PNP inputs reduce DC loading on bus lines Hysteresis at data inputs improves noise margins Typical propagation delay times Inverting 10.5 ns No inverting 12 ns Typical enable/disable time 18 ns Typical power dissipation (enabled)
.
Function Table:
L =>LOW Logic Level
H =>HIGH Logic Level
X =>Either LOW or HIGH Logic Level
Z =>High Impedance
PIN Diagram:
These octal buffers and line drivers are designed specifically to improve both the
performance and density of three-state memory address drivers, clock drivers, and bus-
oriented receivers and transmitters. The designer has a choice of selected combinations of
inverting and non-inverting outputs, symmetrical, active-low output-control (G) inputs, and
complementary output-control (G and G) inputs. The SN74LS and SN74S devices can be
used to drive terminated lines down to 133.
inputs outputs
G A Y
L
L
H
L
H
X
L
H
Z
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Logic Diagram :
Figure 4.23:Pin diagram of IC 74LS244
4.9.3 IC ULN 2003
DESCRIPTION
The ULN2003 is a monolithic high voltage and high current Darlington transistor
arrays. It consists of seven NPN darlington pairs that features high-voltage outputs with
common-cathode clamp diode for switching inductive loads. The collector-current rating of a
single darlington pair is 500mA. The darlington pairs may be paralleled for higher current
capability. Applications include relay drivers, hammer drivers, lamp drivers, display
drivers(LED gas discharge),line drivers, and logic buffers.
FEATURES
500mA rated collector current(Single output) High-voltage outputs: 50V Inputs compatible with various types of logic. Relay driver application
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Figure 4.24: IC ULN2003
Logic Diagram:
Figure 4.25:pin diagram of IC ULN2003
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MELODY GENERATOR(UM66):
General description
Um66 basically a MELODY INTEGRATED CIRCUIT .The UTC
UM66TXXL series are CMOS LSI designed for using in door bell, telephone and toy
application. It is an on-chip ROM programmed for musical performance. Produced by
CMOS technology, the device results in very low power consumption. Since the UTC
UM66TXXL series include oscillation circuits a compact melody module can be
constructed with only a few additional components.
Pin Configuration:
Figure 4.26:Pin configuration of UM66
Pin Description:
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Block Diagram:
Figure 4.27: Block diagram of UM66
Functional description:
Oscillator circuit
The oscillator frequency is used as a time base for tone and beat generators. Its accuracy
affects the quality of the music.
Tone generator
Tone frequencies are oscillator frequencies divided by m, where M is any even number from
64 to 254. Within a melody, 14 scales can be selected including PAUSE code and END
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code. The tone generator is a programmed divider. The range of scales is fromC4:toC6
and range of frequency varies from 258Hz to 32768Hz
Beat Generator
The beat generator is also a programmed divider. It contain 15 available beats as
follows:1/4,1/2, 3/4, 1, 1-1/4, 1-1/2, 1-3/4, 2, 2-1/4, 2-1/2, 2-3/4, 3, 3-1/4, 3-1/2, 3-
3/4.four beats can be selected from these.
Melody ROM
The mask ROM can memorize 64 notes with 6 bits; 4 bits are used for controlling the scalecode and 2 bits are used for the controlling rhythm code
Typical application circuits:
One Short Mode for Piezo: One Short Mode for Piezo
(normal open switch)
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5.PRINTED CIRCUIT BOARD
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.
Solder resist: Areas that should not be soldered may be covered with a polymer solder
resist (solder mask) coating. The solder resist prevents solder from bridging between
conductors and creating short circuits. Solder resist also provides some protection from the
environment. Solder resist is typically 2030 micrometres thick.
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6.SOLDERING
Soldering is a process in which two or more metal items are joined together
by melting and flowing a filler metal (solder) into the joint, the filler metal having a
lower melting point than the workpiece. Soldering differs from welding in that soldering does
not involve melting the work pieces.
There are three forms of soldering, each requiring higher temperatures and each
producing an increasingly stronger joint strength:
1. soft soldering, which originally used a tin-lead alloy as the filler metal,2. silver soldering, which uses an alloy containing silver,3. brazing which uses a brass alloy for the filler.
The alloy of the filler metal for each type of soldering can be adjusted to modify the
melting temperature of the filler. Soldering appears to be a hot glueprocess, but it differs from
gluing significantly in that the filler metals alloy with the workpiece at the junction to form a
gas- and liquid-tight bond.[1]
Soft soldering is characterized by having a melting point of the filler metal below
approximately 400 C (752 F), whereas silver soldering and brazing use higher
temperatures, typically requiring a flame or carbon arc torch to achieve the melting of the
filler. Soft solder filler metals are typically alloys (often containing lead) that
have liquidus temperatures below 350C.In the soldering process, heat is applied to the parts
to be joined, causing the solder to melt and to bond to the workpieces in an alloying process
called wetting. In stranded wire, the solder is drawn up into the wire by capillary action in a
process called 'wicking'. The joint strength is dependent on the filler metal used, where soft
solder is the weakest and the brass alloy used for brazing is the strongest. Soldering, which
uses metal to join metal in a molecular bond has electrical conductivity and is water- and gas-
tight.
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Steps for solderingtechnique:
Here is the step by step procedure for soldering.
1. First of all keep the solder iron plugged in for about a minute and a half beforestarting to use it. By that time the solder iron may get heated to the optimum
temperature [250 degree Celsius].
2. Bend the leads of the different devices that are to be connected to the PCB. For aclean bend, the approximate distance of bend is about 2mm from its body ends.
3. If you are connecting a resistor to the PCB, find its spot and place it into the hole ofthe PCB.
4. After placing the resistor flip the PCB in such a way that the inserted leads lookstowards you.
5. Take the soldering iron in the right hand and the solder wire in the left hand. Thesolder wire must be placed on your finger tips with about 3 inches extending from
your finger grip.
6. Bring both the solder iron tip and the solder wire tip close to the base of the lead ofthe resistor and copper track of the PCB. Make them come in contact at the same
instant at the junction.
7. The solder wire starts to melt as soon as the contact is made.8. When the wire starts melting keep pushing it till the joint has been filled up with the
molten alloy.
9. Move away the solder wire and the solder iron simultaneously and allow the moltenwire to solidify. Thus one lead of the resistor has been connected to the PCB. Do the
same step for the other lead and also for all other components.
Precautions to be taken while Soldering:
For a good heat transfer, the solder wire and the solder iron must be well
cleaned before starting. It must also be pre-tinned with solder. In order to avoid the
overheating of PCB, the components are usually elevated above the PCB. After the
component is inserted in the PCB hole, the excess lead is cut off, thus leaving a length ofabout the radius of the pad.
After soldering, the soldered joints must also be cleaned after it has been solidified.
Some components that are to be soldered may be heat sensitive. For such
components a heat sink may be used on the leads which will reduce the heat transfer to the
components. The only problem is that for such components more heat will be required from
the solder iron to complete the joint.
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De-soldering and Re-soldering:
There may be cases where a soldered PCB may be taken for re-soldering.
The problem is that the solder that is already used has some dissolved base metals that make
it unfit for reuse. If you try to re-solder onto it, the new solder will not properly bond with the
base metal and will cause the formation of a brittle cold solder joint with a crystalline
appearance.
So,before re-soldering it is good practice to de-solder and thus remove the
solder from the joint. For this purpose there are de-soldering equipments called solder
suckers. By doing this a lot of flux is released which will clear the dissolved base metals and
all other contaminants from the copper trace. Thus a bright, shiny, clean junction will be
ready to be re-soldered.
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7.CIRCUIT CONSTRUCTION
Connect the transformer (12-0-12) to the three terminal bases. Connect the
diodes, capacitors and IC 7805 according to the given 5v power supply as shown below:
Connect the IR Leds parallel in series with the 330 ohms resistors. Connect the anode
of Leds to + 5v power supply by means of resistors so as to prevent Leds from d amage.
Connect the cathode of Leds to ground.
Now, connect the photo diodes in reverse bias mode so as the cathode is connected to
+5v power supply with the help of series resistor (10K-ohm) and the anode is connected to
ground terminal. The corresponding outputs from photo diodes are given to the octal buffer
i.e., IC1 74LS244 to store the energy and to drive the various Leds connected at particular
pins.
Here for IC1 we consider the input pins are: 2, 4, 6 and the corresponding output pins
are: 18, 9, and 5 respectively. The 10 pin connected to ground and the 20 pin connected to
+5v power supply.
The output pins of the octal buffer are given to IC2 ULN 2003 (relay driver) to drive
the relays. The input pins of IC2 are: 1, 5, 7 and the corresponding output pins are: 16, 12,
and 10 respectively. These outputs are connected to relays.
The red Leds are connected to the output of IC1 pins.
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8.CIRCUIT DESCRIPTION
The circuit presented here can be used as a lock for importantelectronic/electrical appliances. When card is inserted inside its mechanism, depending upon
the position of punched hole on the card, a particular appliance would be switched on. The
card is inserted just like a floppy disk inside the disk drive. The circuit uses three photo
diodes. When there is no card in the lock, the system remains idle. The IC 74LS244 is active
enabled. The optical sensor unit constructed by using an infrared LED in conjunction with a
matched photo detector (photo diodes) makes the system insensitive to ambient light. Hence
system constitutes negligible noise source as the operating wavelength falls out of the visible
spectrum. The ciruit will be enabled only when there is a continuous radiation from infrared
Led to photo diode.
You can make these cards using a black, opaque plastic sheet or any insulator material
which obstructs the infrared rays to reach photodiodes. A small rectangular notch is made on
this card to indicate proper direction for insertion of the card. When card for any appliance
(say appliance 1) is completely inserted in the mechanism, the particular RED LEDs are
turned on and at the output side particular Led is made to ON. The operation starts as a card
is inserted into the system, the particular photodiode which is unable to detect the radiation
sensed from the corresponding infrared led drives high the IC1 74LS244 integrated circuit
(line driver/ buffer). As the IC output is connected to leds (red and green) respective leds
will turned on.
And the IC2 ULN2003 connected to the output of IC1 used to drive the relays. In this
circuit IC1 (74LS244) is used as buffer with Schmitt trigger. The outputs of this IC1 are
connected to IC2 (ULN2003) which is used as relay driver. IC2 consists of seven high current
relay drivers having integral diodes.
When an input of this IC is made logic high, the corresponding output will go logic
low and relay connected to that pin gets energized. This switches on a specific appliance and
the corresponding LED. Once a specific card is inserted to switch on a specific relay, that
relay gets latched through its second pair of contacts. The only way to reenergize a latched
relay after removal of the corresponding card is to switch off the corresponding switch which
would cut-off the supply to the desired relay.
The +5V and +12V supplies can be obtained with conventional arrangement using a
step-down transformer followed by rectifier, filter and regulator (using 7805 and 7812 etc).
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9.POWER SUPPLY
To make things really simple lets start with a simple
power supply ,and it is also the one they usually give you in your first electronics
project.Well the reason is quite obvious because all electronics circuits require a DC power
supply to work.You really do plug in the wires of your electronic items in AC mains supply
but they do have AC to DC converters to to provide DC to the circuits .All this is done with a
power supply in the right place.
This circuit is a small +5V power supply .The circuit will provide a regulated
voltage to the external circuit which may also I am required in any part of the external circuit
or the whole external circuit .The best part is that you can also use it to convert AC voltage toDC and then regulate it , simply you need a transformer to make the AC main drop down to a
safe value i.e., 12-15 volts and then us a rectifier to convert AC into DC.
This circuit can give +5V output at about 150 mA current, but it can be increased
to 1 A when good cooling is added to 7805 regulator chip.
The circuit has over overload and terminal protection. The capacitors must have
enough high voltage rating to safely handle the input voltage feed to circuit. The circuit is
very easy to build for example into a piece of veroboard.
If you need other voltages than +5V, you can modify the circuit by replacing the
7805 chips with another regulator with different output voltage from regulator 78xx chip
family. The last numbers in the the chip code tells the output voltage. Remember that the
input voltage must be atleast 3V greater than regulator output voltage ot otherwise the
regulator does not work well.
The power supply in the circuit uses a transformer, rectifier and a regulator as shown
Figure 9.1:power supply circuit
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Summary of circuit features:
Brief description of operation: Gives out well regulated +5V output, output currentcapability of 100 mA.
Circuit protection: Built-in overheating protection shuts down output when regulator ICgets too hot.
Circuit complexity: Very simple and easy to build. Circuit performance: Very stable +5V output voltage, reliable operation. Availability of components: Easy to get, uses only very common basic components. Design testing: Based on datasheet example circuit, I have used this circuit succesfully as
part of many electronics projects.
Applications: Part of electronics devices, small laboratory power supply. Power supply voltage: Unreglated DC 8-18V power supply. Power supply current: Needed output current + 5 mA. Component costs: Few dollars for the electronics components + the input transformer cost.
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10.APPLICATIONS
This project is a simple version of card lock system where the advanced versions of thismay lead to vast applications in modern technological world.
These are highly secured devices, hence these may used in banks asSafe DepositLockers.
These are very easily operated ,hence used in any lock system like car door lockingpurpose, home appliances for door locks.
Advantages of Electronic Access Control: An electronic access control system
offers several advantages over traditional locks and keys. Here are some of the most
important to keep in mind when considering your access control options:
1) Electronic Keys are Difficult to Duplicate
While physical keys can be copied very easily, duplicating electronic keys requires a
much higher degree of sophistication. This makes your access system much more secure than
it could ever be with physical keys.
2) You NEVER have to Change the Locks:
An electronic user database means that you never have to change locks at your sites.
If a keycard is ever lost, it can be immediately removed from the database and a new one can
be issued. If an employee leaves your company, his or her access rights can be deleted within
seconds. This greatly lowers your overall exposure to risk.
3) You Only Have to Remember One Key:
With electronic access, your single key or access code grants you access to every door
you need to access, so there's no chance of forgetting the key for a particular door. If you get
to a site where you need access and you are not recognized by the system, a network operator
can add you or your supervisor to the list instantly.
http://www.axisbank.com/webforms/applyonline.asp?ucode=Personal&ccode=OtherServices&pcode=lockers&Applytitle=Apply%20Onlinehttp://www.axisbank.com/webforms/applyonline.asp?ucode=Personal&ccode=OtherServices&pcode=lockers&Applytitle=Apply%20Onlinehttp://www.axisbank.com/webforms/applyonline.asp?ucode=Personal&ccode=OtherServices&pcode=lockers&Applytitle=Apply%20Onlinehttp://www.axisbank.com/webforms/applyonline.asp?ucode=Personal&ccode=OtherServices&pcode=lockers&Applytitle=Apply%20Onlinehttp://www.axisbank.com/webforms/applyonline.asp?ucode=Personal&ccode=OtherServices&pcode=lockers&Applytitle=Apply%20Online7/30/2019 Electronic Cardlock System
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11.RESULT
The assembly of Electronic card lock system is taking up with care, real and
full of responsible. Incorporating the various components as per the circuit diagram on the
printed circuit board solders the unit. After the assembly it is tested as per the design and
specifications. By doing this project we have gained some knowledge about various
components and there operations in practical. We learned many things about various basic
components and uses of them. The electronic card lock system is used for various appliances
by using certain cards.
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12.CONCLUSION
This project is a simplest version of Electronic Card lock system where the
advanced versions lead to the vast applications in the technological world .By using
this system we can increase the security and prevent the unauthorized persons from
opening the lock.
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13.BIBLIOGRAPHY
TEXT BOOKS:
Op-Amps and Linear Integrated Circuits
- Ramakant A. Gayakwad .
Linear integrated circuits
-D. Roy Choudhury, B. Jain.
Integrated Electronics
-Jacob Millman, Christos C. Halkias.
WEBSITES:
Electronics For You.
http://en.wikipedia.org/wiki/Main_Page
http://www.learn-c.com.
http://www.kpsec.freeuk.com.
http://books.google.co.in/books/about/Op_amps_and_linear_integrated_circuits.html?id=KXweAQAAIAAJhttp://books.google.co.in/books/about/Op_amps_and_linear_integrated_circuits.html?id=KXweAQAAIAAJhttp://www.google.co.in/search?tbo=p&tbm=bks&q=inauthor:%22D.+Roy+Choudhury%22http://www.google.co.in/search?tbo=p&tbm=bks&q=inauthor:%22D.+Roy+Choudhury%22http://www.google.co.in/search?tbo=p&tbm=bks&q=inauthor:%22B.+Jain%22http://www.google.co.in/search?hl=en&sa=G&tbo=1&tbm=bks&tbm=bks&q=inauthor:%22Jacob+Millman%22&ei=jXfvTo-qN8jsrAfI-cWQCQ&ved=0CD0Q9Aghttp://www.google.co.in/search?hl=en&sa=G&tbo=1&tbm=bks&tbm=bks&q=inauthor:%22Jacob+Millman%22&ei=jXfvTo-qN8jsrAfI-cWQCQ&ved=0CD0Q9Aghttp://www.google.co.in/search?hl=en&sa=G&tbo=1&tbm=bks&tbm=bks&q=inauthor:%22Jacob+Millman%22&q=inauthor:%22Christos+C.+Halkias%22&ei=jXfvTo-qN8jsrAfI-cWQCQ&ved=0CD4Q9Aghttp://en.wikipedia.org/wiki/Main_Pagehttp://www.learn-c.com/74ls244.pdfhttp://www.kpsec.freeuk.com/http://www.kpsec.freeuk.com/http://www.learn-c.com/74ls244.pdfhttp://en.wikipedia.org/wiki/Main_Pagehttp://www.google.co.in/search?hl=en&sa=G&tbo=1&tbm=bks&tbm=bks&q=inauthor:%22Jacob+Millman%22&q=inauthor:%22Christos+C.+Halkias%22&ei=jXfvTo-qN8jsrAfI-cWQCQ&ved=0CD4Q9Aghttp://www.google.co.in/search?hl=en&sa=G&tbo=1&tbm=bks&tbm=bks&q=inauthor:%22Jacob+Millman%22&ei=jXfvTo-qN8jsrAfI-cWQCQ&ved=0CD0Q9Aghttp://www.google.co.in/search?tbo=p&tbm=bks&q=inauthor:%22B.+Jain%22http://www.google.co.in/search?tbo=p&tbm=bks&q=inauthor:%22D.+Roy+Choudhury%22http://books.google.co.in/books/about/Op_amps_and_linear_integrated_circuits.html?id=KXweAQAAIAAJ7/30/2019 Electronic Cardlock System
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http://www.scitec.uk.com/irleds/notes.php
http://www.datasheetarchive.com
http://www.scitec.uk.com/irleds/notes.phphttp://www.datasheetarchive.com/http://www.datasheetarchive.com/http://www.datasheetarchive.com/http://www.scitec.uk.com/irleds/notes.php7/30/2019 Electronic Cardlock System
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