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[1]
INTRODUCTION
1.1 INTRODUCTION
Aim of this project is to control the unmanned rail gate automatically using embedded
platform. Today often we see news papers very often about the railway accidents happening at
un- attended railway gates. Present project is designed to avoid such accidents if implemented in
spirit. This project is developed in order to help the INDIAN RAILWAYS in making its present
working system a better one, by eliminating some of the loopholes existing in it. Based on the
responses and reports obtained as a result of the significant development in the working system
of INDIAN RAILWAYS,
This project can be further extended to meet the demands according to situation. This can be
further implemented to have control room to regulate the working of the system. Thus becomes
the user friendliness.
In this project AT89c51 Micro controller Integrated Chip plays the main role. The
program for this project is embedded in this Micro controller Integrated Chip and interfaced to
all the peripherals. The timer program is inside the Micro controller IC to maintain all the
functions as per the scheduled time. Stepper motors are used for the purpose of gate control
interfaced with current drivers chip ULN2003 it’s a 16 pin IC.
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1.2 BLOCK DIAGRAM
1.3 DESCRIPTION:
Basically circuit consists of following blocks:
i) Regulated power supply
ii) Microcontroller AT89C51
iii) ULN 2003
iv) Stepper Motors
v) LM 324
vi) Light dependent resistor
Let us take overview of basic blocks, which are as follow
i) REGULATED POWER SUPPLY-:
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REGULATED POWER SUPPLY
89C51
MICRO CONTROLLER ULN
2003STEPPER MOTOR
LM324 LIGHT DEPENDENT
RESISTOR
Fig.1.1 Block diagram of AUTOMATIC RAILWAY GATE CONTROLLER
A regulated power supply is an embedded circuit, or stand alone unit, the function of which is to supply a stable voltage (or less often current), to a circuit or device that must be operated within certain power supply limits. The output from the regulated power supply may be alternating or unidirectional, but is nearly always DC.
The type of stabilization used may be restricted to ensuring that the output remains within certain limits under various load conditions, or it may also include compensation for variations in its own supply source. The latter is much more common today.
APPLICATIONS
D.C. variable bench supply (a bench power supply usually refers to a power supply capable of supplying a variety of output voltages useful for bench testing electronic circuits, possibly with continuous variation of the output voltage, or just some preset voltages; a laboratory (lab) power supply normally implies an accurate bench power supply, while a balanced or tracking power supply refers to twin supplies for use when a circuit requires both positive and negative supply rails).
Mobile Phone power adaptors Regulated power supplies in appliances
ii.) MICROCONTROLLER AT89C51 -:
This is the most important block of the system. Microcontroller is the decision making logical
device which has its own memory, I/O ports, CPU and Clock circuit embedded on a single chip.
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iii) ULN 2003 -:
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-cathodeclamp 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. The ULN2003 has a 2.7kW series base resistor for each darlington pair for operation directly with TTL or 5V CMOS devices.
FEATURES* 500mA rated collector current (Single output)* High-voltage outputs: 50V* Inputs compatible with various types of logic.
* Relay driver application.
iv) STEPPER MOTOR -:
A stepper motor (or step motor) is a brushless DC electric motor that divides a full rotation
into a number of equal steps. The motor's position can then be commanded to move and hold at
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Fig.1.2Microcontroller
one of these steps without any feedback sensor (an open-loop controller), as long as the motor is
carefully sized to the application.
APPLICATION -:
Computer-controlled stepper motors are a type of motion-control positioning system. They are typically digitally controlled as part of an open loop system for use in holding or positioning applications.
In the field of lasers and optics they are frequently used in precision positioning equipment such as linear actuators, linear stages, rotation stages, goniometers, and mirror mounts. Other uses are in packaging machinery, and positioning of valve pilot stages for fluid control systems.
Commercially, stepper motors are used in floppy disk drives, flatbed scanners, computer printers, plotters, slot machines, image scanners, compact disc drives, intelligent lighting and many more devices.
v) LM324 -:
LM324 is a 14pin IC consisting of four independent operational amplifiers (op-amps) compensated in a single package. Op-amps are high gain electronic voltage amplifier with differential input and, usually, a single-ended output. The output voltage is many times higher than the voltage difference between input terminals of an op-amp.These op-amps are operated by a single power supply LM324 and need for a dual supply is eliminated. They can be used as amplifiers, comparators, oscillators, rectifiers etc. The conventional op-amp applications can be more easily implemented with LM324.
5 | P a g eFig.1.3 LM324
vi) LIGHT DEPENDENT RESISTOR -:
A photoresistor or light dependent resistor is a resistor whose resistance decreases with increasing incident light intensity; in other words, it exhibits photoconductivity. It can also be referred to as a photoconductor or CdS device, from "cadmium sulfide," which is the material from which the device is made and that actually exhibits the variation in resistance with light level. Note that although CdS is a semiconductor, it is not doped silicon.
A photoresistor is made of a high resistance semiconductor. If light falling on the device is of high enough frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electron (and its hole partner) conduct electricity, thereby lowering resistance.
Light dependent resistor
Applications
Photoresistors come in many different types. Inexpensive cadmium sulphide cells can be found in many consumer items such as camera light meters, street lights, clock radios, alarm devices, outdoor clocks,solar street lamps and solar road studs etc.
They are also used in some dynamic compressors together with a small incandescent lamp or light emitting diode to control gain reduction and are also used in bed lamps etc.
Lead sulphide (PbS) and indium antimonide (InSb) LDRs (light dependent resistor) are used for the mid infrared spectral region. Ge:Cu photoconductors are among the best far-infrared detectors available, and are used for infrared astronomy and infrared spectroscopy.
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Fig.1.4 LIGHT DEPENDENT RESISTOR
[2]
CIRCUIT DESCRIPTION
2.1 CIRCUIT DIAGRAM -:
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Fig.2.1 Circuit Diagram of automatic gate railway controller
2.2 COMPONENT LIST-:
S.NO. COMPONENT QUANTITY
1 MICRO CONTROLLER ATMEGA 8 1
2 OPERATIONAL AMPLIFIER LM324 2
3 VOLTAGE REGULATOR IC 7805 1
4 IR TRANSMITTER 1
5 IR RECIEVER 1
6 MOTOR DRIVER L 293D 1
7 7-SEGMENT DISPLAY 1
8 STEPPER MOTOR 2
9 VOLTAGE REGULATOR IC 7805 1
10 RESISTOR 7
11 CAPACITOR 2
12 DIODE 6
13 BUZZER 1
14 LED 4
2.3 COMPONENT DESCRIPTION:
2.3.1 PASSIVE ELEMENTS:
1. RESISTORS:
Resistors (R) are the most commonly used of all electronic components, to the point where they
are almost taken for granted. They are "Passive Devices", that is they contain no source of power
or amplification but only attenuate or reduce the voltage signal passing through them. When used
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Tab.1 component list
in DC circuits the voltage drop produced is measured across their terminals as the circuit current
flows through them while in AC circuits the voltage and current are both In-phase Producing0
degree phase shift. In all Electrical and Electronic circuit diagrams and schematics, the most
commonly used resistor symbol is that of a "zigzag" type line with the value of its resistance
given in Ohms.
RESISTORSYMBOL:
The symbol used in schematic and electrical drawings for a Resistor can either be a "zigzag" type
line or a rectangular box.
RESISTORTYPES:
All modern resistors can be classified into four broad groups-
Carbon Composition Resistor: Made of carbon dust or graphite paste, low wattage values.
Film or Cermet Resistor: Made from conductive metal oxide paste, very low wattage
values.
Wire-Wound Resistors: Metallic bodies for heat sink mounting, very high wattage ratings.
Semiconductor Resistors: High frequency/precision surface mount thin film technology.
RESISTOR COLOUR CODE:
The resistance value, tolerance, and watt rating of the resistor are generally printed onto the body
of the resistor as numbers or letters when the resistor is big enough to read the print, such as
large power resistors. When resistors are small such as 1/4W Carbon and Film types, these
specifications must be shown in some other manner as the print would be too small to read. So to
overcome this, small resistors use coloured painted bands to indicate both their resistive value
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and their tolerance with the physical size of the resistor indicating its wattage rating. These
coloured painted bands are generally known as a Resistors Colour Code.
To distinguish left from right there is a gap between the C and D bands.
Band A is first significant figure of component value (left side)
Band B is the second significant figure
Band C is the decimal multiplier
Band D if present, indicates tolerance of value in percent (no color means 20%)
Presets:
These are miniature versions of the standard variable resistor. They are designed to be mounted
directly onto the circuit board and adjusted only when the circuit is built. For example to set the
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frequency of an alarm tone or the sensitivity of a light-sensitive circuit. A small screwdriver or
similar tool is required to adjust presets.
Presets are much cheaper than standard variable resistors so they are sometimes used in projects
where a standard variable resistor would normally be used.
2. CAPACITORS:
Just like the Resistor, the Capacitor or sometimes referred to as a Condenser is a passive device,
and one which stores energy in the form of an electrostatic field which produces a potential
(Static Voltage) across its plates. When a voltage is applied to these plates, a current flows
charging up the plates with electrons giving one plate a positive charge and the other plate an
equal and opposite negative charge. This flow of electrons to the plates is known as the Charging
Current and continues to flow until the voltage across the plates (and hence the capacitor) is
equal to the applied voltage Vc. At this point the capacitor is said to be fully charged and this is
illustrated below.
UNITS OF CAPACITANCE:
Microfarad (μF) 1μF = 10-6 F
Nano farad (nF) 1nF = 10-9F
Pico farad (pF) 1pF = 10 -12F
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Preset Symbol
TYPES OF CAPACITORS:
There are a very large variety of different types of Capacitors available in the market place and
each one has its own set of characteristics and applications from small delicate trimming
capacitors up to large power metal can type capacitors used in high voltage power correction and
smoothing circuits.
Dielectric capacitors:
Dielectric capacitorsare usually of the variable type such as used for tuning transmitters,
receivers and transistor radios. They have a set of fixed plates and a set of moving plates that
mesh with the fixed plates and the position of the moving plates with respect to the fixed plates
determines the overall capacitance. The capacitance is generally at maximum when the plates are
fully meshed.
Variable Capacitor Symbols:
As well as the continuously variable types, preset types are also available called
Trimmers .These are generally small devices that can be adjusted or "pre-set" to a particular
capacitance with the aid of a screwdriver and are available in very small capacitances of 100pF
or less and are non-polarized.
Film capacitors:
Film Capacitors are the most commonly available of all types of capacitors, consisting of a
relatively large family of capacitors with the difference being in their dielectric properties. These
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include polyester (Mylar), polystyrene, polypropylene, polycarbonate, metallized paper, Teflon
etc. Film type capacitors are available in capacitance ranges from 5pF to 100uF depending upon
the actual type of capacitor and its voltage rating. Film capacitors also come in an assortment of
shapes and case styles which include:
•Wrap & Fill (Oval & Round)
•Epoxy Case (Rectangular & Round)
•Metal Hermetically Sealed (Rectangular & Round)
Ceramic capacitors :
Ceramic Capacitors or Disc Capacitors as they are generally called, are made by coating two
sides of a small porcelain or ceramic disc with silver and are then stacked together to make a
capacitor. For very low capacitance values a single ceramic disc of about 3-6mm issued. Ceramic
capacitors have a high dielectric constant (High-K) and are available so that relatively high
capacitances can be obtained in a small physical size. They exhibit large non-linear changes in
capacitance against temperature and as a result are used as de-coupling or by-pass capacitors as
they are also non-polarized devices. Ceramic capacitors have values ranging from a few
Picofarads to one or two microfarads but their voltage ratings are generally quite low. Ceramic
types of capacitors generally have a 3-digit code printed onto their body to identify their
capacitance value. For example, 103 would indicate 10 x 103 PF.
Electrolytic capacitors :
Electrolytic Capacitors are generally used when very large capacitance values are required. Here
instead of using a very thin metallic film layer for one of the electrodes, a semi-liquid electrolyte
solution in the form of a jelly or paste is used which serves as the second electrode (usually the
cathode). The dielectric is a very thin layer of oxide which is grown electro- chemically in
production with the thickness of the film being less than ten microns. This insulating layer is so
thin that it is possible to make large value capacitors of a small size. The majority of electrolytic
types of capacitors are polarized, that is the voltage applied to the capacitor terminals must be of
the correct polarity as an incorrect polarization will break down the insulating oxide layer and
permanent damage may result.
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Electrolytic Capacitors are generally used in DC power supply circuits to help reduce the ripple
voltage or for coupling and decoupling applications. Electrolyte’s generally come in two basic
forms:-
Aluminum Electrolytic
Tantalum Electrolytic capacitors
3) Light Emitting Diodes (LEDs):
A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps
in many devices and are increasingly used for other lighting. Introduced as a practical electronic
component in 1962, early LEDs emitted low-intensity red light, but modern versions are
available across the visible, ultraviolet and infrared wavelengths, with very high brightness.
When a light-emitting diode is forward biased (switched on), electrons are able
to recombine with electron holes within the device, releasing energy in the form of photons. This
effect is called electroluminescence and the Colour of the light (corresponding to the energy of
the photon) is determined by the energy gap of the semiconductor.
Advantages:
Efficiency: LEDs emit more light per watt than incandescent light bulbs. Their efficiency is
not affected by shape and size, unlike fluorescent light bulbs or tubes.
Color: LEDs can emit light of an intended color without using any color filters as traditional
lighting methods need. This is more efficient and can lower initial costs.
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Size: LEDs can be very small (smaller than 2 mm2) and are easily populated onto printed
circuit boards.
On/Off time: LEDs light up very quickly. A typical red indicator LED will achieve full
brightness in under a microsecond. LEDs used in communications devices can have even
faster response times.
Cycling: LEDs are ideal for uses subject to frequent on-off cycling, unlike fluorescent lamps
that fail faster when cycled often, or HID lamps that require a long time before restarting.
Dimming: LEDs can very easily be dimmed either by pulse-width modulation or lowering
the forward current.
Disadvantages:
High initial price: LEDs are currently more expensive, price per lumen, on an initial capital
cost basis, than most conventional lighting technologies. The additional expense partially
stems from the relatively low lumen output and the drive circuitry and power supplies
needed.
Temperature dependence: LED performance largely depends on the ambient temperature
of the operating environment. Over-driving an LED in high ambient temperatures may result
in overheating the LED package, eventually leading to device failure. Adequate heat
sinking is needed to maintain long life.
Voltage sensitivity: LEDs must be supplied with the voltage above the threshold and a
current below the rating. This can involve series resistors or current-regulated power
supplies.
Light quality: Most cool-white LEDs have spectra that differ significantly from a black
body radiator like the sun or an incandescent light. However, the color rendering properties
of common fluorescent lamps are often inferior to what is now available in state-of-art white
LEDs.
Application of LEDs falls into four major categories:
Visual signal application where the light goes more or less directly from the LED to the
human eye, to convey a message or meaning.
Illumination where LED light is reflected from object to give visual response of these
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Generate light for measuring and interacting with processes that do not involve the human
visual system.
Narrow band light sensors where the LED is operated in a reverse-bias mode and is
responsive to incident light instead of emitting light.
2.3.2 IC PIN DESCRIPTION:
1) IC LM324:
The Operational Amplifier is probably the most versatile Integrated Circuit available. It is very
cheap especially keeping in mind the fact that it contains several hundred components. The most
common Op-Amp is the 741 and it is used in many circuits. The OP AMP is a ‘Linear Amplifier’
with an amazing variety of uses. Its main purpose is to amplify (increase) a weak signal - a little
like a Darlington Pair. The OP-AMP has two inputs, INVERTING (-) and NON-INVERTING
(+), and one output at pin 6.The 741 is used in two ways.
a) AN INVERTING AMPLIFIER
Leg two is the input and the output is always reversed. In an inverting amplifier the voltage
enters the 741 chip through leg two and comes out of the 741chip at leg six. If the polarity
is positive going into the chip, it negative by the time it comes out through leg six. The
polarity has been ‘inverted’.
b) A NON-INVERTING AMPLIFIER
Leg three is the input and the output is not reversed. In a non-inverting amplifier the voltage
enters the 741 chip through leg three and leaves the 741 chip through leg six. This time if it is
positive going into the 741 then it is still positive coming out. Polarity remains the same.
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PIN DIAGRAM:
CONNECTIONAL DIAGRAM:
FEATURES
Short Circuit Protection
Excellent Temperature Stability
Internal Frequency Compensation
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Fig.2.2 Pin diagram of LM324 IC
Fig.2.3 Connectional diagram of LM324 IC
High Input Voltage Range
Null of Offset
APPLICATIONS
Audio and Video frequency pre-amplifiers and buffers
Differential amplifiers
Differentiators and integrators
Filters
Precision rectifiers
Precision peak detectors
Voltage and Current regulators
Analog calculators
Analog-to-Digital converters
Digital-to-Analog converters
Voltage clamps
Oscillators and Wave form generators
2) MICROCONTROLLER
A micro-controller can be compared to a small stand-alone computer; it is a very powerful
device, which is capable of executing a series of pre-programmed tasks and interacting with
other hardware devices. Being packed in a tiny integrated circuit (IC) whose size and weight is
usually negligible, it is becoming the perfect controller for robots or any machines requiring
some kind of intelligent automation. A single microcontroller can be sufficient to control a small
mobile robot, an automatic washer machine or a security system. Any microcontroller contains a
memory to store the program to be executed, and a number of input/output lines that can be used
to interact with other devices, like reading the state of a sensor or controlling a motor.
Nowadays, microcontrollers are so cheap and easily available that it is common to use them
instead of simple logic circuits like counters for the sole purpose of gaining some design
flexibility and saving some space. Some machines and robots will even rely on a multitude of
microcontrollers, each one dedicated to a certain task. Most recent microcontrollers are 'In
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System Programmable', meaning that you can modify the program being executed, without
removing the microcontroller from its place.
Today, microcontrollers are an indispensable tool for the robotics hobbyist as well as for the
engineer. Starting in this field can be a little difficult, because you usually can't understand how
everything works inside that integrated circuit, so you have to study the system gradually, a
small part at a time, until you can figure out the whole image and understand how the system
works.
Architecture of a Microcontroller:
19 | P a g eFig.2.4 Architecture of a Microcontroller
Pin diagram:
The pin diagram of a general microcontroller can be given as:
Description
• This is a low-voltage, high-performance CMOS 8-bit microcomputer with 2K bytes of Flash
programmable and erasable read only memory (PEROM).
• The device is manufactured using Atmel's high-density nonvolatile memory technology and
is compatible with the industry-standard MCS-51 instruction set.
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Fig.2.5 pin diagram of microcontroller
• By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel is a powerful
microcomputer which provides a highly-flexible and cost-effective solution to many
embedded control applications.
• The AT89C2051 provides the following standard features: 2K bytes of Flash, 128 bytes of
RAM, 15 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a
full duplex serial port, a precision analog comparator, on-chip oscillator and clock circuitry.
• In addition, the AT89C2051 is designed with static logic for operation down to zero
frequency and supports two software selectable power saving modes.
• The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and
interrupt system to continue functioning.
• The power-down mode saves the RAM contents but freezes the oscillator disabling all other
chip functions until the next hardware reset.
Pin description:
VCC -: Digital supply voltage.
GND -: Ground.
Port B (PB7..PB0) XTAL1/XTAL2/TOSC1/TOSC2
Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). ThePort B output buffers have symmetrical drive characteristics with both high sink and sourcecapability. As inputs, Port B pins that are externally pulled low will source current if the pull-upresistors are activated. The Port B pins are tri-stated when a reset condition becomes active,even if the clock is not running. Depending on the clock selection fuse settings, PB6 can be used as input to the inverting Oscillator amplifier and input to the internal clock operating circuit.Depending on the clock selection fuse settings, PB7 can be used as output from the invertingOscillator amplifier. If the Internal Calibrated RC Oscillator is used as chip clock source, PB7..6 is used as TOSC2..1 input for the Asynchronous Timer/Counter2 if the AS2 bit in ASSR is set.The various special features of Port B are elaborated in “Alternate Functions of Port B” on page58 and “System Clock and Clock Options”
Port C (PC5..PC0) Port C is an 7-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). ThePort C output buffers have symmetrical drive characteristics with both high sink and sourcecapability. As inputs, Port C pins that are externally pulled low will source current if the pull-upresistors are activated. The Port C pins are tri-stated when a reset condition becomes active,even if the clock is not running.
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PC6/RESET
If the RSTDISBL Fuse is programmed, PC6 is used as an I/O pin. Note that the electrical characteristicsof PC6 differ from those of the other pins of Port C.If the RSTDISBL Fuse is unprogrammed, PC6 is used as a Reset input. A low level on this pinfor longer than the minimum pulse length will generate a Reset, even if the clock is not running.
Port D (PD7..PD0)
Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). ThePort D output buffers have symmetrical drive characteristics with both high sink and sourcecapability. As inputs, Port D pins that are externally pulled low will source current if the pull-upresistors are activated. The Port D 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 areset, even if the clock is not running.
AVCC
AVCC is the supply voltage pin for the A/D Converter, Port C (3..0), and ADC (7..6). 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. Note that Port C (5..4) use digital supply voltage, VCC.
AREF
AREF is the analog reference pin for the A/D Converter.
ADC7.6 (TQFP and QFN/MLF Package Only)
In the TQFP and QFN/MLF package, ADC7.6 serve as analog inputs to the A/D converter.These pins are powered from the analog supply and serve as 10-bit ADC channels.
3) IC 7805:
IC7805 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
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+5V regulated power supply. Capacitors of suitable values can be connected at input and output
pins depending upon the respective voltage levels.
Pin diagram:
4) IC L293D:
Introduction: L293D Dual H-Bridge Motor Driver so with one IC we can interface two DC
motors which can be controlled in both clockwise and counter clockwise direction and if you
have motor with fix direction of motion the you can make use of all the four I/Os to connect up
to four DC motors. L293D has output current of 600mA and peak output current of 1.2A per
channel. Moreover for protection of circuit from back EMF output diodes are included within the
IC. The output supply (VCC2) has a wide range from 4.5V to 36V, which has made L293D a
best choice for DC motor driver.
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Fig.2.6.Pin diagram IC 7805
Schematic Diagram: A simple schematic for interfacing a DC motor using L293D is shown.
[3]
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Fig.2.7 Schematic Diagram of IC L293D
FINAL DESIGN
3.1 PCB LAYOUT-:
3.2 TESTING:
A) HARDWARE
B) SOFTWARE
3.2.1 HARDWARE TESTING:
1. Continuity test:
First of all we checked the PCB that all the tracks are as per the design of PCB and
showing continuity with the help of multimeter and PCB layout.
2. Short circuit test:
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FIG 3.1 PCB LAYOUT
Then we checked the PCB for any unwanted short circuits with the help of multimeter and PCB
layout.
3. Soldering:
In the next step, we soldered the required components and then checked that there are no any
unwanted shorts occurred due to soldering without putting IC's and keeping power supply off.
4. Power supply test:
In the next step, we put power supply on and checked whether required voltage is appearing at
the required voltage is appearing at the required points i.e. Vcc and GND at the respective points.
We took care of not connecting IC's in the circuit while performing this test.
3.2.2 SOFTWARESTESTING:
1. Dip Trace:
ROLE IN THE DESIGN: Dip Trace 1.50 proved to be a very handy & easy-to-use tool for the
PCB layout process. Many of its features were utilized leading to an accurate & efficient design.
It has Design Error Check & Electrical Rule Check tools which proved to be helpful in the
design. It is loaded with a huge component list that is categorized in various libraries for giving
simplicity. Placement of components is also very easy & they can be rotated in 360 to⁰
customize the design.
2. AVR STUDIO:
ROLE IN THE DESIGN: avr studio provides IDE for 8051 programming & is very easy to
use. When starting a new project, simply select the microcontroller you use from the Device
Database and the avr IDE sets all Compiler, Assembler, Linker, and Memory options. Its device
database is large which supports many ICs of the 8051 family. A HEX file can be created with
the help of avr which is required for burning onto chip. It has a powerful debugging tool which
detects most of the errors in the program.
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[4]
CODING
Program code-:
#include<reg51.h>
void MSDelay (unsigned int value);
sbit sense1=P1^0;
sbit sense2=P1^1;
sbit buz1=P1^4;
sbit buz2=P1^5;
sbit led=P2^7;
void main ()
{
int i;
P1=0xf0;
buz1=0;
buz2=0;
led=0;
while (1)
{
if (sense1==1 && sense2!=1)
{
buz1=1;
led=1;
for (i=0;i<=2;i++)
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{
P2=0x66;
MSDelay (10);
P2=0xCC;
MSDelay (10);
P2=0x99;
MSDelay (10);
P2=0x33;
MSDelay (10);
}
}
sense1=0;
if (sense2==1 && sense1!=1)
{
buz1=0;
led=0;
for (i=0; i<=2;i++)
{
P2=0x66;
MSDelay (10);
P2=0x33;
MSDelay (10);
P2=0x99;
MSDelay (10);
P2=0xCC;
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MSDelay (10);
}
for(i=0;i<=2;i++)
{
P0=0x66;
MSDelay (10);
P0=0xCC;
MSDelay (10);
P0=0x99;
MSDelay (10);
P0=0x33;
MSDelay (10);
}
}
sense2=0;
if (sense1==1 && sense2==1)
{
buz2=1;
MSDelay (200);
buz2=0;
}
sense1=0;
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sense2=0;
}
}
void MSDelay (unsigned int value)
{
unsigned int x,y;
for(x=0; x<1275;x++)
for(y=0;y<value;y++);
)
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[5]
CONCLUSION
Conclusion-:
From the above discussion and information of this system we, upto now surely comes
to know that it is highly reliable effective and economical at dense traffic area, sub urban area
and the route where frequency of trains is more.
As it saves some auxiliary structure as well as the expenditure on attendant it is
more economical at above mentioned places than traditional railway crossing gate system. We
know that though it is very beneficial but it is also impossible to install such system at
each and every places, but it gives certainly a considerable benefit to us, thereby to our nation.
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[6]
REFERENCE
Reference-:
1. www.Wikipedia.com 2. www.scribd.com 3. www.alldatasheet.com
4. www.8051projects.info
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