MINI PROJECT REPORT ON “Automatic Railway Gate Controller Using Stepper Motor” SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE REWARD OF THE DEGREE BACHELOR OF TECHNOLOGY IN ELECTRONICS & COMMUNICATION ENGINEERING SUBMITTED BY M.KAVITHA 06141A0408 P.MAHESH YADAV 06141A0423 K.SAIDIVYA 06141A0457 UNDER THE ESTEEMED GUIDANCE OF INTERNAL GUIDE EXTERNAL GUIDE Mr.P.ABBAIAH M.Tech S.KISHORE Associate Professor Project Manager Department of E.C.E NSIC
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MINI PROJECT REPORTON
“Automatic Railway Gate Controller Using Stepper Motor”
SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE REWARD OF THE DEGREE BACHELOR OF TECHNOLOGY IN ELECTRONICS & COMMUNICATION ENGINEERING SUBMITTED BY
M.KAVITHA 06141A0408P.MAHESH YADAV 06141A0423K.SAIDIVYA 06141A0457 UNDER THE ESTEEMED GUIDANCE OF
INTERNAL GUIDE EXTERNAL GUIDE Mr.P.ABBAIAH M.Tech S.KISHOREAssociate Professor Project ManagerDepartment of E.C.E NSICS.R.T.I.S.T, Nalgonda. Hyderabad.
Department of electronics and communication engineering SWAMI RAMANANDA TIRTHA INSTITUTE OF SCIENCE & TECHNOLOGY, NALGONDA (NBA Accredited) (Affiliated to J.N.T.U., Hyderabad) Nalgonda-508004 2009-2010
SWAMI RAMANANDA TIRTHA INSTITUTE OF SCIENCE & TECHNOLOGY NALGONDA -508004
Department of Electronics and Communication Engineering
BONAFIDE CERTIFICATE
Certified that this is a miniproject report entitled
Of final year, Electronics and Communication Engineering branch submitted in partial fulfillment of the requirement for the award of B.Tech, degree of the Jawaharlal Nehru Technological University, 2009-2010
Project Guide Head of the Department Mr.P.ABBAIAH M.Tech Mr.P.Lachi Reddy,M.tech,ph.D
Associate Professor ProfessorDepartment of E.C.E Department of E.C.ES.R.T.I.S.T, Nalgonda. S.R.T.I.S.T, Nalgonda.
Principal Dr.S.YADAGIRI S.R.T.I.S.T, Nalgonda
ACKNOWLEDGEMENT
It is our privilege to express our deep gratitude and indebtedness to our
Management & Principal Mr.S.Yadagiri of Swami Ramananda Tirtha Institute of
Science and Technology,Nalgonda for their moral support.
We thank Mr.P.Lachi Reddy,Profeesor & Head of Electronics and
Communication Engineering Department,for his valuable suggestions and cooperation in
the completion of the mini project.
We solemnly offer our sincere gratitude to our internal guide,Mr.P.Abbiah
Depatment of Electronics and Communication,whose constant encouragement and
cooperation has made this miniproject successful.
It is a great pleasure to complete our miniproject in NSIC under the guidance of
Mr.S.Kishore Kumar,we highly grateful to them for their encouragement and open
minded discussion during the mini project work.
We express our heartful thanks to those who have directly or indirectly helped us
in carrying out this mini project successful.
Last but not least we are thankful to our parents.who have stood behind us at all
A unipolar stepper motor has logically two windings per phase, one for each
direction of magnetic field. Since in this arrangement a magnetic pole can be reversed
without switching the direction of current, the commutation circuit can be made very
simple (e.g. a single transistor) for each winding. Typically, given a phase, one end of
each winding is made common: giving three leads per phase and six leads for a typical
two phase motor. Often, these two phase commons are internally joined, so the motor has
only five leads.
Fig 3.2 Unipolar stepper motor coils
In the construction of unipolar stepper motor there are four coils. One end of each coil is tide together and it gives common terminal which is always
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connected with positive terminal of supply. The other ends of each coil are given for interface. Specific color code may also be given. Like in my motor orange is first coil (L1), brown is second (L2), yellow is third (L3), black is fourth (L4) and red for common terminal.
By means of controlling a stepper motor operation we can
1. Increase or decrease the RPM (speed) of it2. Increase or decrease number of revolutions of it3. Change its direction means rotate it clockwise or anticlockwise
To vary the RPM of motor we have to vary the PRF (Pulse Repetition Frequency). Number of applied pulses will vary number of rotations and last to change direction we have to change pulse sequence.
So all these three things just depends on applied pulses. Now there are three different modes to rotate this motor
1. Single coil excitation
2. Double coil excitation3. half coil excitation
Unipolar stepper motors with six or eight wires may be driven using bipolar drivers
by leaving the phase commons disconnected, and driving the two windings of each phase
together [diagram needed]. It is also possible to use a bipolar driver to drive only one
winding of each phase, leaving half of the windings unused [diagram needed].
Bipolar motor:
Bipolar motors have logically a single winding per phase. The current in a
winding needs to be reversed in order to reverse a magnetic pole, so the driving circuit
must be more complicated, typically with an H-bridge arrangement. There are two leads
per phase, none are common.
Static friction effects using an H-bridge have been observed with certain drive
topologies Because windings are better utilized, they are more powerful than a unipolar
motor of the same weight.
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Applications:
Computer-controlled stepper motors are one of the most versatile forms of
positioning systems. They are typically digitally controlled as part of an open loop
system, and are simpler and more rugged than closed loop servo systems.
In the field of 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.
In floppy disk drives, flatbed scanners, computer printers, plotters and many more
The ULN2003 is a high-voltage, high current Darlington drivers comprised of
seven NPN Darlington pairs.
Features:
1) Output current (single output) 500mA MAX.
2) High sustaining voltage output 50V MIN.
3) Input compatible with various types of logic.
Applications:
Relay
Hammers
Lamp and display(LED)drivers
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4.2 PIN DIAGRAM:
Fig:4.2.1 Pin diagram of ULN2003
Features:
No. of pins:16
Temperature, Operating Range:-20°C to +85°C
Transistor Polarity:NPN
No. of Transistors:7
Case Style:DIP-16
Min operating temperature:-20°C
Max operating temperature:85°C
Base Number:2003
Max Output current:500mA
IC Generic Number:2003
Input Type:TTL, CMOS 5V
Output Type: Open Collector
Transistor Type: Power Darlington
Max Input Voltage:5V
Max Output voltage:50V 19
PIN CONNECTIONS OF ULN2003:
Fig 4.2.2 Pin configuration of ULN 2003
The ULN2001A, ULN2002A, ULN2003 and ULN2004Aare high Voltage, high
current Darlington arrays each containing seven open collector Darlington pairs with
common emitters. Each channel rated at 500mAand can withstand peak currents of
600mA.Suppressiondiodesare included for inductive load driving and the inputs are
pinned opposite the outputs to simplify board layout.
These versatile devices are useful for driving a wide range of loads including
solenoids, relays DC motors; LED displays filament lamps, thermal print heads and high
power buffers. The ULN2001A/2002A/2003A and 2004A are supplied in 16 pin plastic
DIP packages with a copper lead frame to reduce thermal resistance. They are available
also in small outline package (SO-16) as ULN2001D/2002D/2003D/2004D.
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SCHEMATIC DIAGRAM OF DARLINGTON PAIR: The circuit below is
a ‘Darlington Pair’ driver. The first transistor’s emitter feeds into the second transistor’s
base and as a result the input signal is amplified by the time it reaches the output.
Darlington pairs are back to back connection of two transistors with some source
resistors.
Fig: 4.2.3 The Darlington pair connection of transistor.
The important point to remember is that the Darlington Pair is made up of two
transistors and when they are arranged as shown in the circuit they are used to amplify
weak signals. The amount by which the weak signal is amplified is called the ‘GAIN’.
.
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CHAPTER 5 LM 324
22LM 324:
5.1 Introduction:
These amplifiers are designed to specifically to operate from a solitary supply
over a wide range of voltages. Also can function when the difference between the two
supplies is 3V to 30V and VCC is at least 1.5V more positive than the input common
mode voltage.
Fig: 5.1 Pin diagram of LM324
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Pin Descriptions
V+ = Supply voltage
GND = Gnd (0V) connection for supply voltage
Input(s) = Input to Op-Amp
Output(s) = Output of Op-Amp
Features: Supply voltage V + : +32VDC or +16VDC
Differential Input Voltage : 32VDC
Input Voltage : -0.3VDC to +32VDC
Power Dissipation : 570mW
Operating Temperature : 0 to 70C degree
Output Current Source : Typical 40mA
Output Current Source : Typical 40mA
Output Current Sink : Typical 20mA
Input Offset Voltage : Typical 2.0mVDC
Operates on a single supply over a range of voltages
Unique features: In the linear mode, the input common-mode voltage range includes ground
and the output voltage can also swing to ground, even though operated from only a
single power supply voltage. The unity gain crossover frequency and the input bias
current are temperature-compensated.
Applications:
In Transducer amplifiers.
DC amplification blocks and conventional operations.
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CHAPTER 6
LIGHT DEPENDENT RESISTOR
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LIGHT DEPENDENT RESISTOR
6.1 Description:
This practical is about using a light dependent resistor (LDR) as a sensor. The
LDR must be part of a voltage divider circuit in order to give an output voltage, Vout ,
which changes with illumination.
A light dependent resistor is a resistor whose resistance decreases with increasing incident light intensity. It can also be referenced as a photo conductor. An LDR 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.
An LDR device can be either intrinsic or extrinsic. An intrinsic semiconductor has its own charge carriers and is not an efficient semiconductor, e.g. silicon. In intrinsic devices the only available electrons are in the valence band, and hence the photon must have enough energy to excite the electron across the entire band gap. Extrinsic devices have impurities, also called do pants, and added whose ground state energy is closer to the conduction band; since the electrons do not have as far to jump, lower energy photons (i.e., longer wavelengths and lower frequencies) are sufficient to trigger the device. If a sample of silicon has some of its atoms replaced by phosphorus atoms (impurities), there will be extra electrons available for conduction.
Fig 6.1.1 Light dependent resistor26
Note that an LDR responds in an extremely non-linear way to the light intensity. The
resistance of a LDR changes from a few meg-ohms in dim light to a few kilo ohms in
bright light (maybe even a few ohms depending upon the light intensity and LDR used.).
So I would suggest that u first connect the LDR as