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this explains about automatic opening and closing of railway gate
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DESCRIPTION CONTENTS PAGE NO.
LIST OF FIGURE
LIST OF TABLES
ABSTRACT 07
CHAPTER -1
INTRODUCTION TO AUTOMATIC RAILWAY SYSTEM
1.1 Introduction 08
1.2Embedded systems 08
1.3 Examples of embedded systems 09
CHAPTER -2
BLOCK DIAGRAM OF AUTOMATIC RAILWAY GATE
2.1 Block diagram 11
2.2 Power supply 11
2.3 Transformers 12
2.4 Rectifiers 13
2.4.1 Types of Rectifiers 13
2.5 Micro controller (AT89S51) 16
2.5.1 Description 16
2.5.2 Features 17
2.5.3 Block diagram and pin diagram 18
2.6 Oscillator 22
B.TECH(EEE),H.I.T.S (COE) Page 1 Department of EEE
CHAPTER -3
3.1 IR COMMUNICATIONS 23
3.1.1 IR Generation 25
3.2 IR LED AND IR SENSOR 26
3.2.1 Schematic circuit of IR sensors 26
3.3 IR TRANSMITTER 28
3.4 IR RECEIVER 30
3.4.1 Use of Infrared detector 31
3.4.2 Theory of sensor circuit 34
3.4.3 Applications of sensors 37
3.5 Introduction to dc motors 39
3.5.1 Introduction 39
3.5.2 Main parts of dc motors 43
3.5.3 Working of dc motor 46
3.5.4 Speed control of dc motor 49
3.6 Motor driver circuit (H-bridge) 52
3.6.1 Operating modes of H-bridge 52
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CHAPTER-4
SOFTWARE EXPLANATION
4.1 Introduction to KEIL software 54
4.2 KEIL software tools (STEPS) 55
CHAPTER -5
CONCLUSION 61
BIBILOGRAPHY 62
REFRENCES 62
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LIST OF FIGURES
FIGURES PAGE NO
1.1 INTERNAL PART OF EMBEDDED SYSTEM 9
2.1 BLOCK DIAGRAM OF PROJECT 11
2.2 COMPONENTS OF POWER SUPPLY 12
2.3 AN ELECTRICAL TRANSFORMER 12
2.4 FULL WAVE RECTIFIER 15
2.5 POSITIVE CYCLE FULL WAVE RECTIFIER 15
2.6 NEGATIVE CYCLE OF FULL WAVE RECTIFIER 15
2.7MICRO CONTROLLERS 16
2.8 BLOCK DIAGRAM OF MICRO CONTROLLER 18
2.9 PIN DIAGRAM OF MICRO CONTROLLER 18
2.10 OSCILLATOR CONNECTIONS 22
2.11 EXTERNAL CLOCK DRIVE CONFIGURATION 22
3.1 VISIBLE SPECTRUMS 23
3.2 CIRCUIT DIAGRAM OF IR SENSOR 28
3.3 IR LED 28
3.4 OP AMPS 30
3.5 IR EMITTER AND IR PHOTO TRANSISTOR 31
3.6 CIRCUIT DIAGRAM OF INFRARED REFLECTANCE SENSOR 32
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3.7 SCHEMATIC DIAGRAM OF SINGLE PAIR IR TRANSMITTER 33
3.8 SCHEMATIC OF SINGLE SENSOR 34
3.9 DESCRIPTION OF OPERATION OF A TYPICAL CIRCUIT 35
3.10 OPERATION OF LED’S 35
3.11 CHARACTERISTICS OF LED’S 36
3.12 COMMUTATORS 43
3.13 BRUSHES 44
3.14 COMMUTATORS AND COMMUTATOR RING 45
3.15 POSITIVE AND NEGATIVE COUNTER CLOCKWISE ROTATION 46
3.16 WORKING OF DC MOTOR 47
3.17 PERIPHERAL OF DC MOTOR 48
3.18 CONSTRUCTION AND WORKING OF DC MOTOR 48
3.19 SPEED CURVE OF DC MOTOR 49
3.20 MOTOR TORQUES LOADING 50
3.21 H-BRIDGE CONNECTED TO A MOTOR 52
3.22 CURRENT FLOWING IN HIGH SIDE AND LOW SIDE 53
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LIST OF TABLES
TABLES PAGE NO
2.1 COMPARISONS OF RECTIFIERS 13
2.2 OPERATIONS OF PORTS 19
3.1 DIFFERENT MATERIALS AND THEIR WAVE LENGTHS 39
3.2 TRUTH TABLE 53
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ABSTRACT:
The railroad industry’s own desire to maintain their ability to provide safe and secure
transport of their customers’ hazardous materials has introduced new challenges in rail security.
Addressing these challenges is important as railroads, and the efficient delivery of their cargo,
play a vital role in the economy of the country.
The train driver always observes the signals placed beside the track. These signals are
controlled from the control room. The green light denotes that the track is free and red light
denotes the track is busy. These signals are controlled based on the train position which is sensed
by the using the IR sensors placed along the track.
The present project is designed to satisfy the security needs of the railways. This system
provides the security in two ways: Automatic gate opening/closing system at track crossing,
signaling for the train driver. The automatic gate opening/closing system is provided with the IR
sensors placed at a distance of few kilometres on the both sides from the crossing road. These
sensors give the train reaching and leaving status to the embedded controller at the gate to which
they are connected. The controller operates (open/close) the gate as per the received signal from
the IR sensors.
B.TECH(EEE),H.I.T.S (COE) Page 7 Department of EEE
CHAPTER-1
INTRODUCTION TO AUTOMATIC RAILWAY GATE
1.1 INTRODUCTION
Whenever ir senses the coming up of train then automatically gate will be closed.
If there is no obstacle found in between ir pairs then gate will be opened.This
particular operation will be handled by the dc motor along with h-bridge interfaced
with micro controller.
Firstly, the required operating voltage for Microcontroller 89C51 is 5V. Hence
the 5V D.C. power supply is needed by the same. This regulated 5V is generated by
first stepping down the 230V to 9V by the step down transformer.
The step downed a.c. voltage is being rectified by the Bridge Rectifier. The
diodes used are 1N4007. The rectified a.c voltage is now filtered using a ‘C’ filter.
Now the rectified, filtered D.C. voltage is fed to the Voltage Regulator. This voltage
regulator allows us to have a Regulated Voltage which is +5V.
The rectified; filtered and regulated voltage is again filtered for ripples using
an electrolytic capacitor 100μF. Now the output from this section is fed to 40th pin of
89c51 microcontroller to supply operating voltage.The microcontroller 89c51 with
Pull up resistors at Port0 and crystal oscillator of 11.0592 MHz crystal in conjunction
with couple of capacitors of is placed at 18 th& 19th pins of 89c51 to make it work
(execute) properly.
1.2 EMBEDDED SYSTEM:
An embedded system is a special-purpose system in which the computer is
completely encapsulated by or dedicated to the device or system it controls. Unlike a general-
purpose computer, such as a personal computer, an embedded system performs one or a few
predefined tasks, usually with very specific requirements. Since the system is dedicated to
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specific tasks, design engineers can optimize it, reducing the size and cost of the product.
Embedded systems are often mass-produced, benefiting from economies of scale.
Personal digital assistants (PDAs) or handheld computers are generally considered
embedded devices because of the nature of their hardware design, even though they are more
expandable in software terms. This line of definition continues to blur as devices expand.
With the introduction of the OQO Model 2 with the Windows XP operating system and ports
such as a USB port — both features usually belong to "general purpose computers", — the
line of nomenclature blurs even more.
Physically, embedded systems ranges from portable devices such as digital
watches and MP3 players, to large stationary installations like traffic lights, factory
controllers, or the systems controlling nuclear power plants.
In terms of complexity embedded systems can range from very simple with a single
microcontroller chip, to very complex with multiple units, peripherals and networks mounted inside
a large chassis or enclosure.
Fig.1.1 INTERNAL PART OF EMBEDDED SYSTEM
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1.3 APPLICATIONS OF EMBEDDED SYSTEMS:
Avionics, such as inertial guidance systems, flight control hardware/software and
other integrated systems in aircraft and missiles
Cellular telephones and telephone switches
Engine controllers and antilock brake controllers for automobiles
Home automation products, such as thermostats, air conditioners, sprinklers, and
security monitoring systems
Handheld calculators
Handheld computers
Household appliances, including microwave ovens, washing machines, television sets,
DVD players and recorders
Medical equipment
Personal digital assistant
Videogame consoles
Computer peripherals such as routers and printers.
Industrial controllers for remote machine operation.
B.TECH(EEE),H.I.T.S (COE) Page 10 Department of EEE
CHAPTER-2
BLOCK DIAGRAM OF AUTOMATIC RAILWAY GATE
2.1 BLOCK DIAGRAM:
Fig:2.1 Block Diagram of project
2.2 POWER SUPPLY:
The power supplies are designed to convert high voltage AC mains electricity to a
suitable low voltage supply for electronic circuits and other devices. A power supply can by
broken down into a series of blocks, each of which performs a particular function. A d.c
power supply which maintains the output voltage constant irrespective of a.c mains
fluctuations or load variations is known as “Regulated D.C Power Supply”. For example a 5V
regulated power supply system as shown below:
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Fig: 2.2 Components of power supply
2.3TRANSFORMER:
A transformer is an electrical device which is used to convert electrical power from one
Electrical circuit to another without change in frequency.Transformers convert AC electricity
from one voltage to another with little loss of power. Transformers work only with AC and
this is one of the reasons why mains electricity is AC. Step-up transformers increase in
output voltage, step-down transformers decrease in output voltage. Most power supplies use a
step-down transformer to reduce the dangerously high mains voltage to a safer low voltage.
The input coil is called the primary and the output coil is called the secondary. There
is no electrical connection between the two coils; instead they are linked by an alternating
magnetic field created in the soft-iron core of the transformer. The two lines in the middle of
the circuit symbol represent the core. Transformers waste very little power so the power out
is (almost) equal to the power in. Note that as voltage is stepped down current is stepped up.
The ratio of the number of turns on each coil, called the turn’s ratio, determines the ratio of
the voltages. A step-down transformer has a large number of turns on its primary (input) coil
which is connected to the high voltage mains supply, and a small number of turns on its
secondary (output) coil to give a low output voltage.
Fig: 2.3An Electrical Transformer
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2.4 RECTIFIER:
A circuit which is used to convert ac to dc is known as RECTIFIER. The process of
conversion ac to dc is called “rectification”
2.4.1 TYPES OF RECTIFIERS:
Half wave Rectifier
Full wave rectifier
1. Centre tap full wave rectifier.
2. Bridge type full bridge rectifier.
Comparison of rectifier circuits:
Parameter
Type of Rectifier
Half wave Full wave Bridge
Number of diodes
1 2 4
PIV of diodes
Vm 2Vm Vm
D.C output voltage Vm/ 2Vm/ 2Vm/
Vdc,at
no-load
0.318Vm 0.636Vm 0.636Vm
Ripple factor 1.21 0.482 0.482
Ripple
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frequency f 2f 2f
Rectification
efficiency 0.406 0.812 0.812
Transformer
Utilization
Factor(TUF)
0.287 0.693 0.812
RMS voltage Vrms Vm/2 Vm/√2 Vm/√2
Table: 2.1 Comparisons of rectifiers
FULL-WAVE RECTIFIER:
From the above comparison we came to know that full wave bridge rectifier as more advantages than the other two rectifiers. So, in our project we are using full wave bridge rectifier circuit.
BRIDGE RECTIFIER:
A bridge rectifier makes use of four diodes in a bridge arrangement to achieve full-
wave rectification. This is a widely used configuration, both with individual diodes wired as
shown and with single component bridges where the diode bridge is wired internally.
A bridge rectifier makes use of four diodes in a bridge arrangement as shown in fig
(a) to achieve full-wave rectification. This is a widely used configuration, both with
individual diodes wired as shown and with single component bridges where the diode bridge
is wired internally.
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Fig: 2.4 Full wave rectifier
OPERATION:
During positive half cycle of secondary, the diodes D2 and D3 are in forward biased while
D1 and D4 are in reverse biased as shown in the fig(b). The current flow direction is shown
in the fig (b) with dotted arrows.
Fig: 2.5 Positive cycle full wave rectifier
During negative half cycle of secondary voltage, the diodes D1 and D4 are in forward biased
while D2 and D3 are in reverse biased as shown in the fig(c). The current flow direction is
shown in the fig (c) with dotted arrows.
Fig: 2.6 Negative cycle of full wave rectifier
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2.5 MICRO CONTROLLER (AT89S51)
2.5.1 DESCRIPTION:
The AT89S51 is a low-power, high-performance CMOS 8-bit microcontroller with 4K
bytes of in-system programmable Flash memory. The device is manufactured using Atmel’s high-
density non-volatile memory technology and is compatible with the industry- standard 80C51
instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-
system or by a conventional non-volatile memory programmer. By combining a versatile 8-bit
CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S51 is a powerful
microcontroller which provides a highly-flexible and cost-effective solution to many embedded
control applications. A Micro controller consists of a powerful CPU tightly coupled with
memory, various I/O interfaces such as serial port, parallel port timer or counter, interrupt
controller, data acquisition interfaces-Analog to Digital converter, Digital to Analog converter,
integrated on to a single silicon chip.
If a system is developed with a microprocessor, the designer has to go for external
memory such as RAM, ROM, EPROM and peripherals. But controller is provided all these
facilities on a single chip. Development of a Micro controller reduces PCB size and cost of design.
One of the major differences between a Microprocessor and a Micro controller is that a controller often deals with bits not bytes as in the real world application.
Intel has introduced a family of Micro controllers called the MCS-51.
Fig: 2.7 Micro controllers
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2.5.2 FEATURES:
• Compatible with MCS-51® Products
• 4K Bytes of In-System Programmable (ISP) Flash Memory
– Endurance: 1000 Write/Erase Cycles
• 4.0V to 5.5V Operating Range
• Fully Static Operation: 0 Hz to 33 MHz
• Three-level Program Memory Lock
• 128 x 8-bit Internal RAM
• 32 Programmable I/O Lines
• Two 16-bit Timer/Counters
• Six Interrupt Sources
• Full Duplex UART Serial Channel
• Low-power Idle and Power-down Modes
.
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2.5.3 BLOCK DIAGRAM AND PIN DIAGRAM:
Fig: 2.8 Block diagram of micro controller
PIN DIAGRAM:
Fig: 2.9 Pin diagram of micro controller
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PIN DESCRIPTION:
VCC - Supply voltage.
GND - Ground.
Port 0:
Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink
eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance
inputs. Port 0 can also be configured to be the multiplexed low-order address/data bus during
accesses to external program and data memory. In this mode, P0 has internal pull-ups. Port 0 also
receives the code bytes during Flash programming and outputs the code bytes during program
verification. External pull-ups are required during program verification.
Port 1:
Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output buffers can
sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the
internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled
low will source current (IIL) because of the internal pull-ups. Port 1 also receives the low-
order address bytes during Flash programming and verification.
Table: 2.2 Operations of ports
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Port 2:
Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output buffers can
sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the
internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are externally being
pulledlow will source current (IIL) because of the internal pull-ups. Port 2 also receives the high-
order address bits and some control signals during Flash programming and verification.
Port 3:
Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output buffers can
sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the
internal pull-ups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled
low will source current (IIL) because of the pull-ups. Port 3 receives some control signals for
Flash programming and verification. Port 3 also serves the functions of various special features of
the AT89S51, as shown in the following table.
RST:
Reset input. A high on this pin for two machine cycles while the oscillator is running resets
the device. This pin drives High for 98 oscillator periods after the Watchdog times out. The
DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default state of
bit DISRTO, the RESET HIGH out feature is enabled.
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ALE/PROG:
Address Latch Enable (ALE) is an output pulse for latching the low byte of the address
during accesses to external memory. This pin is also the program pulse input (PROG) during Flash
programming. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency
and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is
skipped during each access to external data memory. If desired, ALE operation can be disabled by
setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC
instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if
the microcontroller is in external execution mode.
PSEN:
Program Store Enable (PSEN) is the read strobe to external program memory. When the
AT89S51 is executing code from external program memory, PSEN is activated twice each machine
cycle, except that two PSEN activations are skipped during each access to external data memory.
EA/VPP:
External Access Enable. EA must be strapped to GND in order to enable the device to fetch
code from external program memory locations starting at 0000H up to FFFFH. Note, however, that
if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC
for internal program executions. This pin also receives the 12-volt programming enable voltage
(VPP) during Flash programming.
XTAL1:
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
XTAL2:
Output from the inverting oscillator amplifier.
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2.6 OSCILLATOR:
XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier
which can be configured for use as an on-chip oscillator, as shown in Figs 6.2.3. Either a
quartz crystal or ceramic resonator may be used. To drive the device from an external clock
source, XTAL2 should be left unconnected while XTAL1 is driven as shown in Figure
2.11.There are no requirements on the duty cycle of the external clock signal, since the input
to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and
maximum voltage high and low time specifications must be observed.
Fig: 2.10 Oscillator Connections Fig: 2.11 External Clock Drive Configuration
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CHAPTER-3
3.1 IR COMMUNICATIONS
IR wireless is the use of wireless technology in devices or systems that convey data
through infrared (IR) radiation. Infrared is electromagnetic energy at a wavelength or
wavelengths somewhat longer than those of red light. The shortest-wavelength IR borders
visible red in the spectrum. The longest-wavelength IR borders radio waves.
The name means below red, the Latin infra meaning "below". Red is the color of the longest
wavelengths of visible light. Infrared light has a longer wavelength (and so a lower
frequency) than that of red light visible to humans, hence the literal meaning of below red.
INFRARED ENERGY is light that we cannot see, but our bodies can detect as heat. It is part
of the electromagnetic spectrum that includes radio waves, X-rays and visible light. All of
these forms of energy have a specific frequency, as represented in the chart below.
Fig: 3.1 Visible spectrums
Infrared energy is comprised of those frequencies that exist just below the red end of the
visible spectrum, and for cooking properties they have a very unique benefit - when they
strike organic molecules (such as any type of food), they cause the molecules to vibrate,
thereby creating heat. Although almost any type of electromagnetic energy can cause heating,
for the purpose of cooking, infrared energy is the perfect choice.
IR wireless is used for short- and medium-range communications and control. Some systems
operate in line-of-sight mode; this means that there must be a visually unobstructed straight
line through space between the transmitter (source) and receiver (destination). Other systems
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operate in diffuse mode, also called scatter mode. This type of system can function when the
source and destination are not directly visible to each other. An example is a
televisionRemote-control box. The box does not have to be pointed directly at the set,
although the box must be in the same room as the set, or just outside the room with the door
open.
IR wireless technology is used in intrusion detectors; home-entertainment control units; robot
control systems; medium-range, line-of-sight laser communications; cordless microphones,
headsets, modems, and printers and other peripherals.Infrared is an energy radiation with a
frequency below our eyes sensitivity, so we cannot see it. Even that we cannot "see" sound
frequencies, we know that it exist, we can listen them.
Even that we cannot see or hear infrared, we can feel it at our skin temperature sensors.
When you approach your hand to fire or warm element, you will "feel" the heat, but you can't
see it. You can see the fire because it emits other types of radiation, visible to your eyes, but
it also emits lots of infrared that you can only feel in your skin.
INFRARED IN ELECTRONICS
Infra-Red is interesting, because it is easily generated and doesn't suffer electromagnetic
interference, so it is nicely used to communication and control, but it is not perfect, some
other light emissions could contains infrared as well, and that can interfere in this
communication. The sun is an example, since it emits a wide spectrum or radiation.
The adventure of using lots of infra-red in TV/VCR remote controls and other applications,
brought infra-red diodes (emitter and receivers) at very low cost at the market. From now on
you should think as infrared as just a "red" light. This light can means something to the
receiver, the "on or off" radiation can transmit different meanings. Lots of things can generate
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infrared, anything that radiate heat do it, including out body, lamps, stove, oven, friction your
hands together, even the hot water at the faucet.
To allow a good communication using infra-red, and avoid those "fake" signals, it is
imperative to use a "key" that can tell the receiver what is the real data transmitted and what
is fake. As an analogy, looking eye naked to the night sky you can see hundreds of stars, but
you can spot easily a faraway airplane just by its flashing strobe light. That strobe light is the
"key", the "coding" element that alerts us.
Similar to the airplane at the night sky, our TV room may have hundreds of tinny IR sources,
our body and the lamps around, even the hot cup of tea. A way to avoid all those other
sources, is generating a key, like the flashing airplane. So, remote controls use to pulsate its
infrared in a certain frequency. The IR receiver module at the TV, VCR or stereo "tunes" to
this certain frequency and ignores all other IR received. The best frequency for the job is
between 30 and 60 kHz, the most used is around 36 kHz
3.1.1 IR GENERATION
To generate a 36 kHz pulsating infrared is quite easy, more difficult is to receive and
identify this frequency. This is why some companies produce infrared receives, that contains
the filters, decoding circuits and the output shaper, that delivers a square wave, meaning the
existence or not of the 36kHz incoming pulsating infrared.It means that those 3 dollars small
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units, have an output pin that goes high (+5V) when there is a pulsating 36kHz infrared in
front of it, and zero volts when there is not this radiation.
A square wave of approximately 27uS (microseconds) injected at the base of a transistor, can
drive an infrared LED to transmit this pulsating light wave. Upon its presence, the
commercial receiver will switch its output to high level (+5V).If you can turn on and off this
frequency at the transmitter; your receiver's output will indicate when the transmitter is on or
off. Those IR demodulators have inverted logic at its output, when a burst of IR is sensed it
drives its output to low level, meaning logic level = 1.
The TV, VCR, and Audio equipment manufacturers for long use infra-red at their
remote controls. To avoid a Philips remote control to change channels in a Panasonic TV,
they use different codification at the infrared, even that all of them use basically the same
transmitted frequency, from 36 to 50 kHz. So, all of them use a different combination of bits
or how to code the transmitted data to avoid interference.
3.2 IR LED AND IR SENSOR
3.2.1 SCHEMATIC CIRCUIT IR SENSOR
IR LED is used as a source of infrared rays. It comes in two packages 3mm or 5mm.
3mm is better as it is requires less space. IR sensor is nothing but a diode, which is sensitive
for infrared radiation.
This infrared transmitter and receiver are called as IR TX-RX pair. It can be
obtained from any decent electronics component shop and costs less than 10Rs. Following
snap shows 3mm and 5mm IR pairs. Color of IR transmitter and receiver is different.
However you may come across pairs which appear exactly same or even has opposite
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colorsthan shown in above picture and it is not possible to distinguish between TX and RX
visually. In case you will have to take help of multi-meter to distinguish between them.
Here is how you can distinguish between IR TX-RX using DMM:
Connect cathode of one LED to +ve terminal of DMM
Connect anode of the same LED to common terminal of DMM
(means connect LED such that It gets reverse biased by DMM )
Set DMM to measure resistance up to 2M Ohm.
Check the reading.
Repeat above procedure with second LED.
In above process, when you get the reading of the few hundred Kilo Ohms on DMM,
then it indicated that LED that you are testing is IR sensor. In case of IR transmitter
DMM will not show any reading.
Following snap shows typical DMM reading obtained when IR receiver is connected
to it as mentioned above. Second snap shows how sensor’s resistance increases when it is
covered by a finger. Note that, these are just illustrative figures and they will depend upon
sensor as well as DMM that you are using.
While buying an IR sensor, make sure that its reverse resistance in ambient light is
below 1000K. If it is more than this value, then it will not be able to generate sufficient
voltage across external resistor and hence will be less sensitive to small variation in incident
light.
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The circuit diagram::Circuit diagram for IR sensor module is very simple and straight
forward.
Fig: 3.2 Circuit diagram of IR sensor
Circuit is divided into two sections. IR TX and IR RX are to be soldered on small general
purpose Grid PCB. From this module, take out 3 wires of sufficiently long length (say 1 ft).
Then, as shown above, connect them to VCC, present and to ground on main board. By
adjustingpreset, you can adjust sensitivity of the sensor. VCC should be connected to 5V
supply.
3.3 IR TRANSMITTER
Fig: 3.3 IR led
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IR LED emits infrared radiation. This radiation illuminates the surface in front of
LED. Surface reflects the infrared light. Depending on the reflectivity of the surface, amount
of light reflected varies. This reflected light is made incident on reverse biased IR sensor.
When photons are incident on reverse biased junction of this diode, electron-hole pairs are
generated, which results in reverse leakage current. Amount of electron-hole pairs generated
depends on intensity of incident IR radiation. More intense radiation results in more reverse
leakage current. This current can be passed through a resistor so as to get proportional
voltage. Thus as intensity of incident rays varies, voltage across resistor will vary
accordingly.
This voltage can then be given to OPAMP based comparator. Output of the
comparator can be read by uc. Alternatively, you can use on-chip ADC in AVR
microcontroller to measure this voltage and perform comparison in software.
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Fig: 3.4 Op amps
3.4 IR RECEIVER:
A photodiode is a type of photo detector capable of converting light into either current
or voltage, depending upon the mode of operation. 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 will
also use a PIN junction rather than the typical PN junction.
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3.4.1USE OF INFRARED DETECTORS BASICS
Fig: 3.5IR Emitter and IR Photo transistor
An infrared emitter is an LED made from gallium arsenide, which emits near-infrared
energy at about 880nm. The infrared phototransistor acts as a transistor with the base voltage
determined by the amount of light hitting the transistor. Hence it acts as a variable current
source. Greater amount of IR light cause greater currents to flow through the collector-emitter
leads. As shown in the diagram below, the phototransistor is wired in a similar configuration
to the voltage divider. The variable current traveling through the resistor causes a voltage
drop in the pull-up resistor. This voltage is measured as the output of the device.
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Fig: 3.6 Circuit diagram of infrared reflectance sensor
IR reflectance sensors contain a matched infrared transmitter and infrared receiver
pair. These devices work by measuring the amount of light that is reflected into the receiver.
Because the receiver also responds to ambient light, the device works best when well
shielded from ambient light, and when the distance between the sensor and the reflective
surface is small(less than 5mm). IR reflectance sensors are often used to detect white and
black surfaces. White surfaces generally reflect well, while black surfaces reflect poorly. Of
such applications is the line follower of a robot.
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:
Schematic diagram for a single pair of infrared transmitter and receiver
Fig: 3.7 Schematic diagram of single pair IR transmitter
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3.4.2 THEORY OF SINGLE SENSOR CIRCUIT
Fig: 3.8 Schematic of single sensor
To get a good voltage swing , the value of R1 must be carefully chosen.
If IR sensor = a when no light falls on it and IR sensor = b when light falls on it.
The difference in the two potentials is:
Vcc * { a/(a+R1) - b/(b+R1) }
Relative voltage swing = Actual Voltage Swing / Vcc
= Vcc * { a/(a+R1) - b/(b+R1) } / Vcc
= a/(a+R1) - b/(b+R1)
The resistance of the sensor decreases when IR light falls on it. A good sensor will
have near zero resistance in presence of light and a very large resistance in absence of light.
We have used this property of the sensor to form a potential divider. The potential at point ‘2’
isRsensor / (Rsensor + R1). Again, a good sensor circuit should give maximum change in
potential at point ‘2’ for no-light and bright-light conditions. This is especially important is
you plan to use an ADC in place of the comparator To get a good voltage swing , the value of
R1 must be carefully chosen. If Rsensor = a when no light falls on it and Rsensor = b when
light falls on it. The difference in the two potentials is:
Vcc * { a/(a+R1) - b/(b+R1) }
Relative voltage swing = Actual Voltage Swing / Vcc
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= Vcc * { a/(a+R1) - b/(b+R1) } / Vcc
fig: 3.9Description of operation of a typical circuit
fig: 3.10 Operation of led’s
If the emitter and detector (aka phototransistor) are not blocked, then the output on
pin 2 of the 74LS14 will be high (app. 5 Volts). When they are blocked, then the output will
be low (app. 0 Volts). The 74LS14 is a Schmitt triggered hex inverter. A Schmitt trigger is a
signal conditioner. It ensures that above a threshold value, we will always get "clean" HIGH
and LOW signals. Not Blocked Case: Pin 2 High Current from Vcc flows through the
detector. The current continues to flow through the base of Q2. Current from Vcc also flows
through R2, and Q2's Drain and Emitter to ground. As a result of this current path, there will
be no current flowing through Q1's base. The signal at U1's pin 1 will be low, and so pin 2
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will be high. Therefore only the moderated signal from the light emitter can be detected.
Of course the detector must not be saturated by ambient light; this is effective when the
detector
Fig: 3.11 Characteristics of led’s
the line position is compared to the centre value to be tracked, the position error is processed
with Proportional /Integral/ Diffence filter. to generate steering command. The line following
robot tracks the line in PID control that the most popular algorithm for servo control. The
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proportional term is the common process in the servo system. It is only a gain amplifier
without time dependent process. The differential term is applied in order to improve the
response to disturbance, and it also compensate phase lag at the controlled object. The D term
will be required in most case to stabilize tracking motion. The I term that boosts DC gain is
applied in order to remove left offset error, however, it often decrease servo stability due to
its phase lag. When any line sensing error has occurred for a time due to getting out of line or
end of line, the motors are stopped and the microcontroller enters sleep state of zero power
consumption. Typical Examples of infrared Transmitter and Receiver installation.
3.4.3 APPLICATIONS OF SENSORS
A photodiode is a type of photo detector capable of converting light into either
current or voltage, depending upon the mode of operation. 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 fibre connection to allow light to reach the
sensitive part of the device. Many diodes designed for use specifically as a photodiode will
also use a PIN junction rather than the typical PN junction.
PRINCIPLE OF POERATION
A photodiode is a PN junction or PIN structure. When a photon of sufficient energy
strikes the diode, it excites an electron thereby creating a mobile electron and a positively
charged electron hole. 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.
PHOTOVOTAIC MODE
When used in zero bias or photovoltaic mode, the flow of photocurrent out of the
device is restricted and a voltage builds up. The diode becomes forward biased and "dark
current" begins to flow across the junction in the direction opposite to the photocurrent. This
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mode is responsible for the photovoltaic effect, which is the basis for solar cells—in fact, a
solar cell is just an array of large photodiodes.
PHOTOCONDUCTIVE MODE
In this mode the diode is often (but not always) reverse biased. 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 (known as saturation
or back current) along its direction while the photocurrent remains virtually the same.
Although this mode is faster, the photovoltaic mode tends to exhibit less electronic noise
(The leakage current of a good PIN diode is so low – < 1nA – that the Johnson–Nyquist noise
of the load resistance in a typical circuit often dominates.)Avalanche photodiodes have a
similar structure to regular photodiodes, but they are operated with much higher reverse bias.
This allows each photo-generated carrier to be multiplied by avalanche breakdown, resulting
in internal gain within the photodiode, which increases the effective responsively of the
device.
PHOTOTRANSISTERS also consist of a photodiode with internal gain. A phototransistor
is in essence nothing more than a bipolar transistor that is encased in a transparent case so
that light can reach the base-collector junction. The electrons that are generated by photons in
the base-collector junction are injected into the base, and this current is amplified by the
transistor operation. Note that although phototransistors have a higher responsivity for light
they are unable to detect low levels of light any better than photodiodes. Phototransistors also
have slower response times.
MATERIALS
The material used to make a photodiode is critical to defining its properties, because
only photons with sufficient energy to excite electrons across the material's bandgap will
produce significant photocurrents.
Materials commonly used to produce photodiodes include:
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Material Wavelength range (nm)
Silicon 190–1100
Germanium 400–1700
Indium gallium
arsenide800–2600
Lead sulphide <1000-3500
Table: 3.1 Different materials and their wave lengths
Because of their greater band gap, silicon-based photodiodes generate less noise than
germanium-based photodiodes, but germanium photodiodes must be used for wavelengths
longer than approximately 1 µm.
Since transistors and ICs are made of semiconductors, and contain P-N junctions,
almost every active component is potentially a photodiode. Many components, especially
those sensitive to small currents, will not work correctly if illuminated, due to the induced
photocurrents. In most components this is not desired, so they are placed in an opaque
housing. Since housings are not completely opaque to X-rays or other high energy radiation,
these can still cause many ICs to malfunction due to induced photo-currents.
3.5 INTRODUCTION TO DC MOTORS:
3.5.1INTRODUCTION:
The brushed DC motor is one of the earliest motor designs. Today, it is the motor of
choice in the majority of variable speed and torque control applications.
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Advantages:
Easy to understand design
Easy to control speed
Easy to control torque
Simple, cheap drive design
Easy to understand design
The design of the brushed DC motor is quite simple. A permanent magnetic field is
created in the stator by either of two means:
Permanent magnets
Electro-magnetic windings
If the field is created by permanent magnets, the motor is said to be a "permanent magnet
DC motor" (PMDC). If created by electromagnetic windings, the motor is often said to be a
"shunt wound DC motor" (SWDC). Today, because of cost-effectiveness and reliability, the
PMDC motor is the motor of choice for applications involving fractional horsepower DC
motors, as well as most applications up to about three horsepower. At five horsepower and
greater, various forms of the shunt wound DC motor are most commonly used. This is
because the electromagnetic windings are more cost effective than permanent magnets in this
power range.
Caution: If a DC motor suffers a loss of field (if for example, the field power connections
are broken), the DC motor will immediately begin to accelerate to the top speed which the
loading will allow. This can result in the motor flying apart if the motor is lightly loaded. The
possible loss of field must be accounted for, particularly with shunt wound DC motors.
Opposing the stator field is the armature field, which is generated by a changing
electromagnetic flux coming from windings located on the rotor. The magnetic poles of the
armature field will attempt to line up with the opposite magnetic poles generated by the stator
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field. If we stopped the design at this point, the motor would spin until the poles were
opposite one another, settle into place, and then stop -- which would make a pretty useless
motor!
However, we are smarter than that. The section of the rotor where the electricity
enters the rotor windings is called the commutator. The electricity is carried between the
rotorand the stator by conductive graphite-copper brushes (mounted on the rotor) which
contact rings on stator. Imagine power is supplied:
The motor rotates toward the pole alignment point. Just as the motor would get to this
point, the brushes jump across a gap in the stator rings. Momentum carries the motor forward
over this gap. When the brushes get to the other side of the gap, they contact the stator rings
again and -- the polarity of the voltage is reversed in this set of rings! The motor begins
accelerating again, this time trying to get to the opposite set of poles. (The momentum has
carried the motor past the original pole alignment point.) This continues as the motor rotates.
In most DC motors, several sets of windings or permanent magnets are present to
smooth out the motion. Easy to control speed controlling the speed of a brushed DC motor is
simple. The higher the armature voltage, the faster the rotation. This relationship is linear to
the motor's maximum speed. The maximum armature voltage which corresponds to a motor's
rated speed (these motors are usually given a rated speed and a maximum speed, such as
1750/2000 rpm) are available in certain standard voltages, which roughly increase in
conjunction with horsepower. Thus, the smallest industrial motors are rated 90 VDC and 180
VDC. Larger units are rated at 250 VDC and sometimes higher. Specialty motors for use in
mobile applications are rated 12, 24, or 48 VDC.
Other tiny motors may be rated 5 VDC. Most industrial DC motors will operate
reliably over a speed range of about 20:1 -- down to about 5-7% of base speed. This is much
better performance than the comparable AC motor. This is partly due to the simplicity of
control, but is also partly due to the fact that most industrial DC motors are designed with
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variable speed operation in mind, and have added heat dissipation features which allow lower
operating speeds.
Easy to control torque
In a brushed DC motor, torque control is also simple, since output torque is
proportional to current. If you limit the current, you have just limited the torque which the
motor can achieve. This makes this motor ideal for delicate applications such as textile
manufacturing.
Simple, cheap drive design
The result of this design is that variable speed or variable torque electronics are easy
to design and manufacture. Varying the speed of a brushed DC motor requires little more
than a large enough potentiometer. In practice, these have been replaced for all but sub-
fractional horsepower applications by the SCR and PWM drives, which offer relatively
precisely control voltage and current. Common DC drives are available at the low end (up to
2 horsepower) for under US$100 -- and sometimes under US$50 if precision is not important.
Large DC drives are available up to hundreds of horsepower. However, over about 10
horsepower careful consideration should be given to the price/performance tradeoffs with AC
inverter systems, since the AC systems show a price advantage in the larger systems. (But
they may not be capable of the application's performance requirements).
Disadvantages
Expensive to produce
Can't reliably control at lowest speeds
Physically larger
High maintenance
Dust
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3.5.2 MAIN PARTS OF DC MOTOR
Armature
A D.C. motor consists of a rectangular coil made of insulated copper wire wound on a
soft iron core. This coil wound on the soft iron core forms the armature. The coil is mounted
on an axle and is placed between the cylindrical concave poles of a magnet.
Commutator
A commutator is used to reverse the direction of flow of current. Commutator is a
copper ring split into two parts C1 and C2. The split rings are insulated form each other and
mounted on the axle of the motor. The two ends of the coil are soldered to these rings. They
rotate along with the coil. Commutator rings are connected to a battery. The wires from the
battery are not connected to the rings but to the brushes which are in contact with the rings.
Fig: 3.12 Commutators
Brushes
Two small strips of carbon, known as brushes press slightly against the two split
rings, and the split rings rotate between the brushes. The carbon brushes are connected to a
D.C. source.
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When the coil is powered, a magnetic field is generated around the armature. The left side of
the armature is pushed away from the left magnet and drawn towards the right, causing rotation.
Fig: 3.13 Brushes
When the coil turns through 900, the brushes lose contact with the commutator and the
current stops flowing through the coil. However the coil keeps turning because of its own
momentum. Now when the coil turns through 1800, the sides get interchanged. As a result the
commutator ring C1 is now in contact with brush B2 and commutator ring C2 is in contact
with brush B1. Therefore, the current continues to flow in the same direction.
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Fig: 3.14Commutators and Commutator Ring
PARAMETRS OF THE DC MOTRS:
1. Direction of rotation
2. Motor Speed
3. Motor Torque
4. Motor Start and Stop
Direction of Rotation:
A DC Motor has two wires. We can call them the positive terminal and the negative
terminal, although these are pretty much arbitrary names (unlike a battery where these
polarities are vital and not to be mixed!). On a motor, we say that when the + wire is
connected to + terminal on a power source, and the - wire is connected to the - terminal
source on the same power source, the motor rotates clockwise (if you are looking towards the
motor shaft). If you reverse the wire polarities so that each wire is connected to the opposing
power supply terminal, then the motor rotates counter clockwise. Notice this is just an
arbitrary selection and that some motor manufacturers could easily choose the opposing
convention. As long as you know what rotation you get with one polarity, you can always
connect in such a fashion that you get the direction that you want on a per polarity basis.
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Fig: 3.15Positive And Negative Counter Clockwise Rotation
DC Motor Rotation vs Polarity:
Facts:
DC Motor rotation has nothing to do with the voltage magnitude or the current
magnitude flowing through the motor.
DC Motor rotation does have to do with the voltage polarity and the direction of
the current flow.
3.5.3 WORKING OF DC MOTOR
In any electric motor, operation is based on simple electromagnetism. A current-
carrying conductor generates a magnetic field; when this is then placed in an external
magnetic field, it will experience a force proportional to the current in the conductor, and to
the strength of the external magnetic field. As you are well aware of from playing with
magnets as a kid, opposite (North and South) polarities attract, while like polarities (North
and North, South and South) repel. The internal configuration of a DC motor is designed to
harness the magnetic interaction between a current-carrying conductor and an external
magnetic field to generate rotational motion.
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Fig: 3.16Working of dc motor
PRINCIPLE
When a rectangular coil carrying current is placed in a magnetic field, a torque acts on
the coil which rotates it continuously.
When the coil rotates, the shaft attached to it also rotates and thus it is able to do mechanical
work.
Every DC motor has six basic parts -- axle, rotor (a.k.a., armature), stator,
commutator, field magnet(s), and brushes. In most common DC motors (and all that
BEAMers will see), the external magnetic field is produced by high-strength permanent
magnets1. The stator is the stationary part of the motor -- this includes the motor casing, as
well as two or more permanent magnet pole pieces. The rotor (together with the axle and
attached commutator) rotates with respect to the stator. The rotor consists of windings
(generally on a core), the windings being electrically connected to the commutator. The
above diagram shows a common motor layout -- with the rotor inside the stator (field)
magnets.
The geometry of the brushes, commentator contacts, and rotor windings are such that when
power is applied, the polarities of the energized winding and the stator magnet(s) are
misaligned, and the rotor will rotate until it is almost aligned with the stator's field magnets.
As the rotor reaches alignment, the brushes move to the next commentator contacts, and
energize the next winding. Given our example two-pole motor, the rotation reverses the
direction of current through the rotor winding, leading to a "flip" of the rotor's magnetic field,
driving it to continue rotating.
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In real life, though, DC motors will always have more than two poles (three is a very common
number). In particular, this avoids "dead spots" in the commutator. You can imagine how with
our example two-pole motor, if the rotor is exactly at the middle of its rotation (perfectly
aligned with the field magnets), it will get "stuck" there. Meanwhile, with a two-pole motor,
there is a moment where the commutator shorts out the power supply (i.e., both brushes touch
both commutator contacts simultaneously). This would be bad for the power supply, waste
energy, and damage motor components as well. Yet another disadvantage of such a simple
motor is that it would exhibit a high amount of torque "ripple" (the amount of torque it could
produce is cyclic with the position of the rotor).
Fig: 3.17 Peripheral of dc motor
Construction and Working
Fig: 3.18 Construction and working of dc motor
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3.5.4 SPEED CONTROL OF DC Motor:
Whereas the voltage polarity controls DC motor rotation, voltage magnitude controls
motor speed. Think of the voltage applied as a facilitator for the strengthening of the
magnetic field. In other words, the higher the voltage, the quicker will the magnetic field
become strong. Remember that a DC motor has an electromagnet and a series of permanent
magnets.
The applied voltage generates a magnetic field on the electromagnet portion. This
electromagnet field is made to oppose the permanent magnet field. If the electromagnet field
is very strong, then both magnetic entities will try to repel each other from one side, as well
as attract each other from the other side. The stronger the induced magnetic field, the quicker
will this separation/attraction will try to take place. As a result, motor speed is directly
proportional to applied voltage.
Fig: 3.19Speed Curve of Dc Motor
Motor Speed Curve:
One aspect to have in mind is that the motor speed is not entirely lineal. Each motor
will have their own voltage/speed curve. One thing I can guarantee from each motor is that at
very low voltages, the motor will simply not move. This is because the magnetic field
strength is not enough to overcome friction. Once friction is overcome, motor speed will start
to increase as voltage increase.The following video shows the concept of speed control and
offers some ideas on how this can be achieved.
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Motor Torque:
In the previous segment I kind of described speed as having to do with the strength of
the magnetic field, but this is in reality misleading. Speed has to do with how fast the
magnetic field is built and the attraction/repel forces are installed into the two magnetic
structures. Motor strength, on the other hand, has to do with magnetic field strength. The
stronger the electromagnet attracts the permanent magnet, the more force is exerted on the
motor load.
Per example, imagine a motor trying to lift 10 pounds of weight. This is a force that
when multiplied by a distance (how much from the ground we are lifting the load) results in
WORK. This WORK when exerted through a predetermined amount of time (for how long
we are lifting the weight) gives us power. But whatever power came in, must come out as
energycan not be created or destroyed. So that you know, the power that we are supplying to
the motor is computed by
P = IV
Where P is power, I is motor current and V is motor voltage
Hence, if the voltage (motor speed) is maintained constant, how much load we are moving
must come from the current? As you increase load (or torque requirements) current must also
increase.
Fig: 3.20Motor Torques Loading
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Motor Loading
One aspect about DC motors which we must not forget is that loading or increase of
torque cannot be infinite as there is a point in which the motor simply can not move. When
this happens, we call this loading “Stalling Torque”. At the same time this is the maximum
amount of current the motor will see, and it is refer to Stalling Current. Stalling deserves a
full chapter as this is a very important scenario that will define a great deal of the controller to
be used. I promise I will later write a post on stalling and its intricacies.
Motor Start and Stop
You are already well versed on how to control the motor speed, the motor torque and
the motor direction of rotation. But this is all fine and dandy as long as the motor is actually
moving. How about starting it and stopping it? Are these trivial matters? Can we just ignore
them or should we be careful about these aspects as well? You bet we should!Starting a
motor is a very hazardous moment for the system. Since you have an inductance whose
energy storage capacity is basically empty, the motor will first act as an inductor. In a sense,
it should not worry us too much because current cannot change abruptly in an inductor, but
the truth of the matter is that this is one of the instances in which you will see the highest
currents flowing into the motor. The start is not necessarily bad for the motor itself as in fact
the motor can easily take this Inrush Current. The power stage, on the other hand and if not
properly designed for, may take a beating.
Once the motor has started, the motor current will go down from inrush levels to
whatever load the motor is at. Per example, if the motor is moving a few gears, current will
be proportional to that load and according to torque/current curves.
Stopping the motor is not as harsh as starting. In fact, stopping is pretty much a
breeze. What we do need to concern ourselves is with how we want the motor to stop. Do we
want it to coast down as energy is spent in the loop, or do we want the rotor to stop as fast as
possible? If the later is the option, then we need braking. Braking is easily accomplished by
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shorting the motor outputs. The reason why the motor stops so fast is because as a short is
applied to the motor terminals, the Back EMF is shorted. Because Back EMF is directly
proportional to speed, making Back EMF = 0, also means making speed = 0.
3.6 MOTORDRIVER CIRCUIT:(H-BRIDGE)
The name "H-Bridge" is derived from the actual shape of the switching circuit which
control the motion of the motor. It is also known as "Full Bridge". Basically there are four
switching elements in the H-Bridge as shown in the figure below.
3.6.1 OPERATING MODES OF H-BRIDGE
Fig: 3.21H-Bridge Connected To a Motor
As you can see in the figure above there are four switching elements named as "High
side left", "High side right", "Low side right", "Low side left". When these switches are
turned on in pairs motor changes its direction accordingly. Like, if we switch on High side
left and Low side right then motor rotate in forward direction, as current flows from Power
supply through the motor coil goes to ground via switch low side right. This is shown in the
figure below.
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Fig: 3.22Current Flowing in High Side And Low Side
Similarly, when you switch on low side left and high side right, the current flows in opposite
direction and motor rotates in backward direction. This is the basic working of H-Bridge. We
can also make a small truth table according to the switching of H-Bridge explained above.
Truth Table
High Left High Right Low Left Low Right Description
On Off Off On Motor runs clockwise
Off On On Off Motor runs anti-clockwise
On On Off Off Motor stops or decelerates
Off Off On On Motor stops or decelerates
Table: 3.2 Truth table
CHAPTER-4
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SOFTWARE EXPLANATION:
4.1 INTRODUCTION TO KEIL SOFTWARE:
Software’s used are:
*Keil software for c programming
*Express PCB for lay out design
*Express SCH for schematic design
What's New in µVision4?
µVision3 adds many new features to the Editor like Text Templates, Quick Function
Navigation, and Syntax Colouring with brace high lighting Configuration Wizard for dialog
based start-up and debugger setup. µVision3 is fully compatible to µVision4 and can be used
in parallel with µVision4.
What is µVision4?
µVision3 is an IDE (Integrated Development Environment) that helps you write, compile,
and debug embedded programs. It encapsulates the following components:
A project manager.
A make facility.
Tool configuration.
Editor.
A powerful debugger.
To help you get started, several example programs (located in the \C51\Examples, \C251\
Examples, \C166\Examples, and \ARM\...\Examples) are provided.
HELLO is a simple program that prints the string "Hello World" using the Serial
Interface.
MEASURE is a data acquisition system for analog and digital systems.
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TRAFFIC is a traffic light controller with the RTX Tiny operating system.
SIEVE is the SIEVE Benchmark.
DHRY is the Dhrystone Benchmark.
WHETS are the Single-Precision Whetstone Benchmark.
Additional example programs not listed here are provided for each device architecture.
Building an Application in µVision4
To build (compile, assemble, and link) an application in µVision4, you must:
1. Select Project - (for example, 166\EXAMPLES\HELLO\HELLO.UV4).
2. Select Project - Rebuild all target files or Build target.
4.2KEIL SOFTWARE TOOL (STEPS):
Click on the Keil vision Icon on Desktop
1. The following fig will appear
2. Click on the Project menu from the title bar
3. Then Click on New Project
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4. Save the Project by typing suitable project name with no extension in u r own
folder sited in either C:\ or D:\
5. Then Click on save button above.
6. Select the component for u r project. I.e. Atmel……
7. Click on the + Symbol beside of Atmel
8. Select AT89C52 as shown below
9. Then Click on “OK”
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10. The Following fig will appear
11. Then Click either YES or NO………mostly “NO”
12. Now your project is ready to USE
13. Now double click on the Target1, you would get another option “Source group 1”
as shown in next page.
14. Click on the file option from menu bar and select “new”
15. The next screen will be as shown in next page, and just maximize it by double
clicking on its blue boarder.
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16. Now start writing program in either in “C” or “ASM”
17. For a program written in Assembly, then save it with extension “. asm” and for
“C” based program save it with extension “ .C”
18. Now right click on Source group 1 and click on “Add files to Group Source”
19. Now you will get another window, on which by default “C” files will appear.
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20. Now select as per your file extension given while saving the file
21. Click only one time on option “ADD”
22. Now Press function key F7 to compile. Any error will appear if so happen.
23. If the file contains no error, then press Control+F5 simultaneously.
24. The new window is as follows
25. Then Click “OK”
26. Now Click on the Peripherals from menu bar, and check your required port as
shown in fig below
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27. Drag the port a side and click in the program file.
28. Now keep Pressing function key “F11” slowly and observe.
29. You are running your program successfully
CHAPTER-5
5.1 CONCLUSION:
The accidents are avoided at places where there is no person managing the railway
crossing gates. Here we use the stepper motor to open and close the gates automatically when
it is rotated clockwise or anticlockwise direction. When the train arrives in a particular
direction the transmitter IR senses and generates appropriate signal, then at the same time the
receiver IR receives the signal and generates an interrupt. When the interrupt is generated the
B.TECH(EEE),H.I.T.S (COE) Page 60 Department of EEE
stepper motor rotates in clockwise direction. When the interrupt ends the stepper motor
rotates in anti-clock wise direction.
BIBILOGRAPHY
The 8051 Micro controller and Embedded Systems
-Muhammad Ali Mazidi
-Janice GillispieMazidi
The 8051 Micro controller Architecture, Programming & Applications
-Kenneth J.Ayala
Fundamentals Of Microprocessors and Micro computers
B.TECH(EEE),H.I.T.S (COE) Page 61 Department of EEE
-B.Ram
Microprocessor Architecture, Programming & Applications
-Ramesh S. Gaonkar
Electronic Components
-D.V. Prasad
Wireless Communications
- Theodore S. Rappaport
Mobile Tele Communications
- William C.Y. Lee
REFRENCES:
www.national.com
www.atmel.com
www.microsoftsearch.com
www.geocities.com
B.TECH(EEE),H.I.T.S (COE) Page 62 Department of EEE
STUDENT DATA
1. NAME: N.RAKESH
PHONE NO: 9866576918
EMAIL ID: [email protected]
ROLE IN THE PROJECT: PROJECT LEADER
PERMANENT ADDRESS:LIGH-527, PRASANTHI NAGAR, APHB COLONY,
MOULA-ALI, 500040.
2. NAME: V.SANDEEP
PHONE NO: 9494244100
EMAIL ID: [email protected]
ROLE IN THE PROJECT: INFORMATION GATHERER ABOUT EMBEDDED
SYSTEM CIRCUIT VERIFIER
PERMANENT ADDRESS:LIGH-529, PRASANTHI NAGAR, APHB COLONY, MOULA-ALI, 500040
3. NAME: G.SHIVA
PHONE NO: 9493420053
EMAIL ID: [email protected]
ROLE IN THE PROJECT: CIRCUIT DESIGNER AND COMPONENT GATHERER
PERMANENT ADDERESS: UPPAL DEPOT.
B.TECH(EEE),H.I.T.S (COE) Page 63 Department of EEE