Chapter 1
INTRODUCTION
The basic idea
behind auto driving system using 3G and MEMS is to provide safety and secured
way of driving without drivers .Basically this idea can be used by military
purpose for tracking and bombing purpose .As we are living in this techno world
we want advancement in each and everything so it gives a assured safety way of
driving and we can monitor the control of our car through our mobile set and
keep a continuous track of on our mobile through 3G and the noisy effects are
eliminated by using MEMS microphone which is very cheap as compared to our
normal microphone and it is based on real time system. In this there is no
limitations of controlling if 3G facilities are available we can control our
car by large distance also .
Technologies used
in this are 3G,MEMS microphone .The programming is done in EMBEDDED C in KEIL
software.
The next chapter2
deals with Auto Driving System using 3g and MEMS.
Chapter 2
AUTO DRIVING SYSTEM
A driverless car is
a vehicle equipped with an autopilot system, which is capable of driving
from one point to another without input from a human operator.
This
technology is distinct from vehicles with a remote operator such as Bombardier Advanced Rapid Transit Systems .
The
proposed advantages include:
§ Transporting loads in dangerous zones such
as battlefields or disaster-zones.
§ Reducing the costs and inconvenience of
employing drivers (for example for public
transport or commercial vehicles),
§ Managing traffic flow to increase road
capacity
§ Relieving vehicle occupants from driving and
navigating chores, so allowing them to concentrate on other tasks or to take
rest during their journeys,
§ Reducing directional steering and velocity
errors and corrections implicit in manually
controlled vehicles
§ To avoid accidents,
§ To accurately align vehicles with platforms
to facilitate disabled access and cargo loading
§ To reduce lane width and safety margins
(especially bus-lanes on narrow roads, as in Castellon, Spain)
Some proposed systems depend on
infrastructure-based guidance systems (i.e. systems embedded in or near the
road itself), while more advanced systems propose to simulate human perception
and decision-making during steering of a car via advanced computer software
linked to a range of sensors such as cameras, radar and GPS.
While common in futurist scenarios
for a long time, driverless cars in an unstructured (i.e. non-prepared,
constantly changing) free environment are still in their infancy as of 2011,
and there are no vehicles in existence that are approved for use in
environments where they would encounter normal human drivers - though much
progress was made in the late 2000s. Driverless passenger car programs include
the 800 million Euro EC EUREKA Prometheus Project on autonomous vehicles, the together passenger vehicles from the Netherlands, the ARGO research project from Italy, the DARPA Grand Challenge from the USA,
and Google driverless car.
2.1 Social
Impact
Driverless
cars may yield advantages of increasing roadway capacity by reducing the
distances between cars, reduce congestion by efficiently controlling the flow
of traffic, and increase safety by eliminating driver error.
According
to urban designer and futurist Michael E. Arth,
driverless electric vehicles—in conjunction with the increased use of virtual reality for
work, travel, and pleasure—could reduce the world's vehicles (estimated to be
800,000,000)[19] to
a fraction of that number within a few decades. Arth
claims that this would be possible if almost all private cars requiring
drivers, which are not in use and parked 90% of the time, would be traded for
public self-driving taxis that would be in near constant use. This would also
allow for getting the appropriate vehicle for the particular need—a bus could
come for a group of people, a limousine could come for a special night out, and
a Segway could come for a short trip down the street for one person. Children
could be chauffeured in supervised safety, DUIs would no
longer exist, and 41,000 lives could be saved each year in the U.S. alone.
The next chapter 3 deals with Block Diagram of our
project.
Fig 3.1-This figure shows Block
Diagram of our project.
Chapter 4
HARDWARE
AND SOFTWARE REQUIREMENTS
Hardware Requirements
POWER SUPPLY:
5V DC
MICROCONTROLLER :
AT89C52
DTMF:
MT8870
RELAY:
12V
RELAY:
6V
PREAMPLIFIER CIRCUIT:
KA2201
LED
Software Requirements
EMBEDDED C
KEIL VERSION COMPILER
The next chapter 5 deals with the power supply of our project.
Chapter
5
POWER SUPPLY
Power supply units contains adaptor,
regulator and filter .This will convert ac voltage into desired dc voltage
.Adaptor is used to step down the voltage ,regulator is used for removing AC
components and filter is used to provide pure DC.
Fig 5.1- This figure shows basic block diagram
of Power supply.
5.1 Vital
role of power supply is system
The microcontroller and other
devices get power supply from ac to dc adaptor through 7805 a 5v regulator. The
adopter output voltage will be 12 dc non-regulated. The 7805 voltage regulators
are used to convert 12v to 5v dc.
5.1.1 Transformer
Fig
5.2- This figure shows the information about transformer.
The low voltage Ac output is
suitable for lamps, heater and special Ac motor .it is not suitable for
electronic circuits unless they include a rectifier and smoothing capacitor.
Vs/Vp=Ns/Np.........................................................................................................(eq-:5.1)
5.1.2
Transformer with Rectifier
Fig
5.3- This figure shows the information of Transformer with rectifier
The varying DC output is suitable
for lamps, heaters, and standard motors .It
is not suitable for electronic circuits unless they include a smoothing
capacitor.
5.1.3
Transformer with Rectifier and
Smoothing Capacitor
Fig: 5.4-This figure shows Transformer with
rectified and smoothing capacitor output
The
smooth DC output has a small ripple.
Fig 5.5-This figure shows the output of smoothing
capacitor
5.1.4 BRIDGE
RECTIFIER
Fig 5.6-This figure shows the information
about Bridge rectifier
This circuit provides full-wave
rectification without the necessity of a center-tapped transformer. In
applications where a center-tapped, or split-phase, source is unavailable,
this is the only practical method of full-wave rectification.
In addition to requiring more diodes
than the center-tap circuit, the full-wave bridge suffers a slight performance
disadvantage as well: the additional voltage drop caused by current having to
go through two diodes
in each half-cycle rather than through only one. With a low-voltage source such
as the one you're using (6 volts RMS), this disadvantage is easily measured.
Compare the DC voltage reading across the motor terminals with the reading
obtained from the last experiment, given the same AC power supply and the same
motor.
5.1.5 Smoothing Capacitor
Fig 5.7 Smoothing
capacitor Fig 5.8
Smoothing capacitor output
A capacitor is a device which stores electrical
charge. In the most simple terms it can be thought of as being similar
to a rechargeable battery in that it stores power to be used at a later time. Charging a capacitor is simply a matter or putting voltage across
its legs until current stops flowing. Capacitors are an essential component in the majority of electronic
circuits.
There
are many uses of capacitors in renewable energy generation, however one of the most important is in
smoothing the output of abridge rectifier after it has converted AC electricity (typically
generated by wind turbine generators etc) into DC (used to charge batteries and
power many low voltage devices)
5.9 Overview of
power supply.
Fig-5.10:This figure shows information about voltage
regulator
In
electronics, a linear regulator is a voltage regulator based on an active device (such as a bipolar
junction transistor, field effect transistor or vacuum tube) operating in its "linear region" (in
contrast, a switching regulator is based on a transistor forced to act as an on/off
switch) or passive devices like zener
diodes operated
in their breakdown region. The regulating device is made to act like a variable resistor, continuously adjusting a voltage divider network to maintain a constant output voltage. It is
very inefficient compared to a switched-mode
power supply, since it sheds the difference
voltage by dissipating heat.
5.2 Design
Transformer
|
:
12-0-12v, 1A
|
Bridge
rectifier
|
:
W083M
|
Capacitor
|
:
25v, 1000uf,-1uf
|
Voltage
Regulator
|
:
LM7805
|
The next chapter 6 deals with
Microcontroller.
Chapter 6
MICROCONTROLLER
6.1 INTRODUCTION
A microcontroller (sometimes
abbreviated µC, uC or MCU) is a small computer on a single integrated circuit containing
a processor core, memory, and programmable input/output peripherals.
Program memory in the form of NOR
flash or OTP ROM is
also often included on chip, as well as a typically small amount of RAM. Microcontrollers are designed for
embedded applications, in contrast to the microprocessors used
in personal
computers or other general purpose applications.
Microcontrollers
are used in automatically controlled products and devices, such as automobile
engine control systems, implantable medical devices, remote controls, office
machines, appliances, power tools, and toys. By reducing the size and cost
compared to a design that uses a separate microprocessor, memory, and
input/output devices, microcontrollers make it economical to digitally control
even more devices and processes. Mixed signal microcontrollers are common,
integrating analog components needed to control non-digital electronic systems.
Some
microcontrollers may use Four-bit words and operate at clock rate frequencies
as low as 4 kHz, for low power consumption (milliwatts or microwatts).
They will generally have the ability to retain functionality while waiting for
an event such as a button press or other interrupt; power consumption while
sleeping (CPU clock and most peripherals off) may be just nanowatts, making
many of them well suited for long lasting battery applications. Other
microcontrollers may serve performance-critical roles, where they may need to
act more like a digital signal
processor (DSP), with higher clock speeds and
power consumption.
Fig.6.1-This figure shows
the basic view of a microcontroller.
6.1.1 Features
Compatible MCS®-51 Products
4K Bytes of Flash Memory
4.0V to 5.5V Operating Range
Static Operation: 0 Hz to 33 MHz
Three-level Program 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 Power Modes
Interrupts
Watchdog Timers
Dual Data Pointer
Power-off Flag
Fast Programming Time
Flexible ISP Programming
Green (Pb/Halide-free) Packaging
4K Bytes of Flash Memory 4.0V to 5.5V Operating Range Static Operation: 0 Hz to 33 MHz Three-level Program 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 Power Modes Interrupts Watchdog Timers Dual Data Pointer Power-off Flag Fast Programming Time Flexible ISP Programming Green (Pb/Halide-free) Packaging
Fig,6.2-This figure shows Microcontroller
pin diagram.
Fig 6.3-This figure shows simple
microcontroller block diagram.
6.1.2 Types of Microcontrollers
As
of 2008 there are several dozen microcontroller architectures and vendors
including:
§ Infineon
Microcontroller: 8, 16, 32
Bit microcontrollers for automotive and industrial applications[6]
and
many others, some of which are used in very narrow range of applications or are
more like applications processors than microcontrollers. The microcontroller
market is extremely fragmented, with numerous vendors, technologies, and
markets. Note that many vendors sell (or have sold) multiple architectures.
6.2 Higher integration
In contrast to general-purpose CPUs,
micro-controllers may not implement an external address or data bus as they
integrate RAM and non-volatile memory on the same chip as the CPU. Using fewer
pins, the chip can be placed in a much smaller, cheaper package.
Integrating the memory and other
peripherals on a single chip and testing them as a unit increases the cost of
that chip, but often results in decreased net cost of the embedded system as a
whole. Even if the cost of a CPU that has integrated peripherals is slightly
more than the cost of a CPU and external peripherals, having fewer chips
typically allows a smaller and cheaper circuit board, and reduces the labor
required to assemble and test the circuit board.
A
micro-controller is a single integrated
circuit, commonly with the
following features:
§ central processing unit - ranging from small and simple 4-bit processors to complex 32- or 64-bit
processors
§ discrete input and output bits, allowing
control or detection of the logic state of an individual package pin
§ other serial communications interfaces like I²C, Serial Peripheral Interface and Controller Area Network for system interconnect
§ many include analog-to-digital converters,
some include digital-to-analog converters
§ in-circuit programming and debugging support
This
integration drastically reduces the number of chips and the amount of wiring
and circuit board space that would be needed to produce
equivalent systems using separate chips. Furthermore, on low pin count devices
in particular, each pin may interface to several internal peripherals, with the
pin function selected by software. This allows a part to be used in a wider
variety of applications than if pins had dedicated functions. Micro-controllers
have proved to be highly popular in embedded systems since their introduction in the 1970s.
Some microcontrollers use a Harvard architecture: separate memory buses for instructions and data, allowing accesses to
take place concurrently. Where a Harvard architecture is used, instruction
words for the processor may be a different bit size than the length of internal
memory and registers; for example: 12-bit instructions used with 8-bit data
registers.
The decision of which peripheral to
integrate is often difficult. The microcontroller vendors often trade operating
frequencies and system design flexibility against time-to-market requirements
from their customers and overall lower system cost. Manufacturers have to
balance the need to minimize the chip size against additional functionality.
Microcontroller architectures vary
widely. Some designs include general-purpose microprocessor cores, with one or
more ROM, RAM, or I/O functions integrated onto the package. Other designs are
purpose built for control applications. A micro-controller instruction set
usually has many instructions intended for bit-wise operations to make control
programs more compact For example, a general purpose processor might
require several instructions to test a bit in a register and branch if the bit
is set, where a micro-controller could have a single instruction to provide
that commonly-required function.
Microcontrollers
typically do not have a math coprocessor, so floating point arithmetic is performed by software.
6.3
EMBEDDED DESIGN
A microcontroller can be considered
a self-contained system with a processor, memory and peripherals and can be
used as an embedded system.[1] The majority of microcontrollers in use today are
embedded in other machinery, such as automobiles, telephones, appliances, and
peripherals for computer systems. These are calledembedded
systems. While some embedded systems are very
sophisticated, many have minimal requirements for memory and program length,
with no operating system, and low software complexity. Typical input and output
devices include switches, relays, solenoids, LEDs, small or custom LCD displays, radio frequency devices, and sensors for data
such as temperature, humidity, light level etc. Embedded systems usually have
no keyboard, screen, disks, printers, or other recognizable I/O devices of apersonal computer, and may lack human interaction devices of any kind.
6.4 INTERRUPTS
Microcontrollers must provide real time (predictable, though not necessarily fast) response to
events in the embedded system they are controlling. When certain events occur,
an interrupt system can signal the processor to suspend processing
the current instruction sequence and to begin an interrupt service routine (ISR, or "interrupt handler"). The ISR will
perform any processing required based on the source of the interrupt before
returning to the original instruction sequence. Possible interrupt sources are
device dependent, and often include events such as an internal timer overflow,
completing an analog to digital conversion, a logic level change on an input
such as from a button being pressed, and data received on a communication link.
Where power consumption is important as in battery operated devices, interrupts
may also wake a microcontroller from a low power sleep state where the
processor is halted until required to do something by a peripheral event.
6.5
PROGRAMS
Microcontroller programs must fit in
the available on-chip program memory, since it would be costly to provide a
system with external, expandable, memory. Compilers and assemblers are used to
convert high-level language and assembler language codes into a compact machine code for storage in the microcontroller's memory. Depending
on the device, the program memory may be permanent, read-only memory that can
only be programmed at the factory, or program memory may be field-alterable
flash or erasable read-only memory
6.5.1 PROGRAMMING ENVIRONMENTS
Microcontrollers
were originally programmed only in assembly language,
but various high-level programming languages are
now also in common use to target microcontrollers. These languages are either
designed specially for the purpose, or versions of general purpose languages
such as the C programming language. Compilersfor
general purpose languages will typically have some restrictions as well as
enhancements to better support the unique characteristics of microcontrollers.
Some microcontrollers have environments to aid developing certain types of
applications. Microcontroller vendors often make tools freely available to make
it easier to adopt their hardware.
Many
microcontrollers are so quirky that they effectively require their own
non-standard dialects of C, such as SDCC for the 8051, which prevent using
standard tools (such as code libraries or static analysis tools) even for code
unrelated to hardware features. Interpreters are often used to hide such low
level quirks.
Interpreter firmware
is also available for some microcontrollers. For example, BASIC on the
early microcontrollers Intel 8052 BASIC
and FORTH on
the Zilog Z8 as well as some
modern devices. Typically these interpreters support interactive
programming.
Simulators are
available for some microcontrollers, such as in Microchip's MPLAB environment
and the Revolution Education PICAXE range.
These allow a developer to analyze what the behavior of the microcontroller and
their program should be if they were using the actual part. A simulator will
show the internal processor state and also that of the outputs, as well as
allowing input signals to be generated. While on the one hand most simulators
will be limited from being unable to simulate much other hardware in a system,
they can exercise conditions that may otherwise be hard to reproduce at will in
the physical implementation, and can be the quickest way to debug and analyze problems.
Recent
microcontrollers are often integrated with on-chip debug circuitry
that when accessed by an in-circuit emulator via JTAG, allow debugging
of the firmware with a debugger.
6.6
APPLICATIONS OF MICROCONTROLLERS
From the
earliest microcontrollers to today, six-transistor SRAM is almost always used
as the read/write working memory, with a few more transistors per bit used in
the register file. MRAM could
potentially replace it as it is 4-10 times denser which would make it more cost
effective.
In
addition to the SRAM, some microcontrollers also have internal EEPROM for data
storage; and even ones that do not have any (or not enough) are often connected
to external serial EEPROM chip (such as the BASIC Stamp) or external
serial flash memory chip.
A few
recent microcontrollers beginning in 2003 have "self-programmable"
flash memory.
The
earliest microcontrollers used hard-wired or mask ROM to store firmware. Later
microcontrollers (such as the early versions of the Freescale 68HC11 and
early PIC microcontrollers) had quartz windows that
allowed ultraviolet light in to erase the EPROM.
The
Microchip PIC16C84,
introduced in 1993, was the first microcontroller to use EEPROM to
store firmware
MRAM could
potentially be used to store firmware.
6.7 DESIGN
6.7.1 CRYSTAL
FREQUENCY
From datasheet frequency
of clock required for microcontroller must be in the range 1 to 16 mhz hence
used crystal frequency of 11.058 mhz.
6.7.2 Pin connection of microcontroller
Fig.6.4-This figure shows Microcontroller pin
diagram.
·
AT89C52 microcontroller Pin Diagram and Pin
Functions.
PSEN: Program Store Enable is the read strobe to external Program
Memory. When the device is executing out of external Program Memory, PSEN is
activated twice each machine cycle (except that two PSEN activations are
skipped during accesses to external Data Memory). PSEN is not activated when
the device is executing out of internal Program Memory.
EA/VPP: When EA is held high the CPU executes out of internal Program
Memory (unless the Program Counter exceeds 0FFFH in the 80C51). Holding EA low
forces the CPU to execute out of external memory regardless of the Program Counter
value. In the 80C31, EA must be externally wired low. In the EPROM devices,
this pin also receives the programming supply voltage (VPP) during EPROM
programming.
XTAL1: Input to the inverting oscillator amplifier.
XTAL2: Output from the inverting oscillator amplifier.
Port 0: Port 0 is an 8-bit open drain bidirectional port. As an open drain
output port, it can sink eight LS TTL loads. Port 0 pins that have 1s written
to them float, and in that state will function as high impedance inputs. Port 0
is also the multiplexed low-order address and data bus during accesses to
external memory. In this application it uses strong internal pullups when
emitting 1s. Port 0 emits code bytes during program verification. In this
application, external pullups are required.
Port 1: Port 1 is an 8-bit bidirectional I/O port with internal pullups. Port
1 pins that have 1s written to them are pulled high by the internal pullups,
and in that state can be used as inputs. As inputs, port 1 pins that are
externally being pulled low will source current because of the internal
pullups.
Port 2: Port 2 is an 8-bit bidirectional I/O port with internal pullups. Port 2
emits the high-order address byte during accesses to external memory that use
16-bit addresses. In this application, it uses the strong internal pullups when
emitting 1s.
Port 3: Port 3 is an 8-bit bidirectional I/O port with internal pullups.
It also serves the functions of various special features of the 80C51 Family as
follows:
Port Pin Alternate Function
P3.0 RxD (serial input port)
P3.1 TxD (serial output port)
P3.2 INT0 (external interrupt 0)
P3.3 INT1 (external interrupt 1)
P3.4 T0 (timer 0 external input)
P3.5 T1 (timer 1 external input)
P3.6 WR (external data memory write strobe)
P3.7 RD (external data memory read strobe)
VCC: Supply voltage
The next chapter 7 deals with
LED.
Chapter 7
LED
7.1 INTRODUCTION
A light-emitting diode 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 color of
the light (corresponding to the energy of the photon) is determined by the energy gap of
the semiconductor. An LED is often small in area (less than 1 mm2),
and integrated optical components may be used to shape its radiation pattern. LEDs
present many advantages over
incandescent light sources including lower energy consumption, longer lifetime,
improved robustness, smaller size, faster switching, and greater durability and
reliability. LEDs powerful enough for room lighting are relatively expensive
and require more precise current and heat management than
compact fluorescent lamp sources
of comparable output.
Light-emitting
diodes are used in applications as diverse as replacements for aviation lighting, automotive
lighting (particularly brake lamps, turn signals
and indicators)
as well as in traffic
signals. The compact size, the possibility of narrow bandwidth, switching
speed, and extreme reliability of LEDs has allowed new text and video displays
and sensors to be developed, while their high switching rates are also useful
in advanced communications technology. Infrared LEDs
are also used in the remote control units
of many commercial products including televisions, DVD players, and other
domestic appliances.
Fig:7.1:-This figure shows LED view.
7.2 PARTS OF LED
1. Epoxy lens
2. Wire bond
3. Reflective cavity
Fig:7.2 –This figure shows various parts of LED.
7.3 Practical use
The first commercial LEDs were commonly used as
replacements for incandescent and neon indicator lamps, and in seven-segment displays, first in expensive equipment such as laboratory and
electronics test equipment, then later in such appliances as TVs, radios,
telephones, calculators, and even watches (see list of signal
uses). These red LEDs were bright enough only
for use as indicators, as the light output was not enough to illuminate an
area. Readouts in calculators were so small that plastic lenses were built over
each digit to make them legible. Later, other colors grew widely available and
also appeared in appliances and equipment. As LED materials technology grew
more advanced, light output rose, while maintaining efficiency and reliability
at acceptable levels. The invention and development of the high power white
light LED led to use for illumination, which is fast replacing incandescent and
fluorescent lighting.(see list of illumination
applications). Most LEDs were made in the very
common 5 mm T1¾ and 3 mm T1 packages, but with rising power output,
it has grown increasingly necessary to shed excess heat to maintain
reliability, so more
complex packages have been adapted for efficient heat dissipation. Packages for
state-of-the-art high power LEDs bear little resemblance to early LEDs.
7.4 Working
The LED
consists of a chip of semiconducting material doped with
impurities to create a p-n junction. As in other
diodes, current flows easily from the p-side, or anode, to the n-side, or cathode, but not in the reverse
direction. Charge-carriers—electrons and holes—flow
into the junction from electrodes with
different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in
the form of a photon.
The wavelength of
the light emitted, and thus its color depends on the band gap energy
of the materials forming thep-n
junction. In silicon or germanium diodes,
the electrons and holes recombine by a non-radiative transition which
produces no optical emission, because these are indirect
band gap materials. The materials used for the
LED have a direct
band gap with energies corresponding to
near-infrared, visible or near-ultraviolet light.
LED
development began with infrared and red devices made with gallium arsenide.
Advances in materials sciencehave
enabled making devices with ever-shorter wavelengths, emitting light in a
variety of colors.
LEDs are
usually built on an n-type substrate, with an electrode attached to the p-type
layer deposited on its surface. P-type substrates, while less common, occur as
well. Many commercial LEDs, especially GaN/InGaN, also use sapphire substrate.
Most
materials used for LED production have very high refractive
indices. This means that much light will be reflected back into the
material at the material/air surface interface. Thus, light extraction
in LEDs is an important aspect of LED
production, subject to much research and development.
Fig.7.3-This figure
shows the working of LED.
7.5 I-V DIAGRAM OF LED
Fig.7.4-This figure shows I-V
diagram of LED.
A
convoluted chip surface with angled facets similar
to a jewel or fresnel lens can
increase light output by allowing light to be emitted perpendicular to the chip
surface while far to the sides of the photon emission point.
The
ideal shape of a semiconductor with maximum light output would be a microsphere with
the photon emission occurring at the exact center, with electrodes penetrating
to the center to contact at the emission point. All light rays emanating from
the center would be perpendicular to the entire surface of the sphere,
resulting in no internal reflections. A hemispherical semiconductor would also
work, with the flat back-surface serving as a mirror to back-scattered photons.
7.6
Types of LED
Fig.7.5-This figure shows
various types of LED.
7.6.1 Ultraviolet and blue LED
Blue
LEDs are based on the wide band gap semiconductors
GaN (gallium nitride)
and InGaN (indium
gallium nitride). They can be added to existing red and green LEDs to produce
the impression of white light, though white LEDs today rarely use this
principle.
The
first blue LEDs were made in 1971 by Jacques Pankove (inventor of the gallium
nitride LED) at RCA Laboratories These
devices had too little light output to be of much practical use. In August of
1989, Cree Inc. introduced the first commercially available blue LED. In
the late 1980s, key breakthroughs in GaN epitaxial growth
and p-type doping ushered
in the modern era of GaN-based optoelectronic devices. Building upon this
foundation, in 1993 high brightness blue LEDs were demonstrated.
By the
late 1990s, blue LEDs had become widely available. They have an active region
consisting of one or more InGaNquantum
wells sandwiched between thicker layers of
GaN, called cladding layers. By varying the relative InN-GaN fraction in the
InGaN quantum wells, the light emission can be varied from violet to amber.
AlGaN aluminium gallium
nitride of varying AlN fraction can be used to
manufacture the cladding and quantum well layers for ultraviolet LEDs, but
these devices have not yet reached the level of efficiency and technological
maturity of the InGaN-GaN blue/green devices. If the active quantum well layers
are GaN, instead of alloyed InGaN or AlGaN, the device will emit
near-ultraviolet light with wavelengths around 350–370 nm. Green LEDs
manufactured from the InGaN-GaN system are far more efficient and brighter than
green LEDs produced with non-nitride material systems.
With
nitrides containing aluminium, most often AlGaN and AlGaInN,
even shorter wavelengths are achievable. Ultraviolet LEDs in a range of
wavelengths are becoming available on the market. Near-UV emitters at
wavelengths around 375–395 nm are already cheap and often encountered, for
example, as black light lamp
replacements for inspection of anti-counterfeiting UV
watermarks in some documents and paper currencies. Shorter wavelength diodes,
while substantially more expensive, are commercially available for wavelengths
down to 247 nm.]As
the photosensitivity of microorganisms approximately matches the absorption
spectrum of DNA, with a peak at about
260 nm, UV LED emitting at 250–270 nm are to be expected in
prospective disinfection and sterilization devices. Recent research has shown
that commercially available UVA LEDs (365 nm) are already effective
disinfection and sterilization devices.
Deep-UV wavelengths were obtained in laboratories using aluminium nitride (210 nm),
boron nitride (215 nm) and diamond (235 nm).
7.6.2 White LED
There
are two primary ways of producing high intensity white-light using LEDs. One is
to use individual LEDs that emit three primary
colors—red, green, and blue—and then mix all the colors to form white
light. The other is to use a phosphor material to convert monochromatic light
from a blue or UV LED to broad-spectrum white light, much in the same way a
fluorescent light bulb works.
Due to metamerism, it is possible to have quite
different spectra that appear white.
7.6.3 Phosphor based LED
This
method involves coating an
LED of one color (mostly blue LED made of InGaN) with phosphor of
different colors to form white light; the resultant LEDs are called phosphor-based white LEDs. A
fraction of the blue light undergoes the Stokes shift being
transformed from shorter wavelengths to longer. Depending on the color of the
original LED, phosphors of different colors can be employed. If several
phosphor layers of distinct colors are applied, the emitted spectrum is
broadened, effectively raising thecolor rendering index (CRI)
value of a given LED.
Phosphor
based LEDs have a lower efficiency than normal LEDs due to the heat loss from
the Stokes shift and also other phosphor-related degradation issues. However,
the phosphor method is still the most popular method for making high
intensity white LEDs. The design and production
of a light source or light fixture using a monochrome emitter with phosphor
conversion is simpler and cheaper than a complex RGBsystem,
and the majority of high intensity white LEDs presently on the market are
manufactured using phosphor light conversion.
The
greatest barrier to high efficiency is the seemingly unavoidable Stokes energy
loss. However, much effort is being spent on optimizing these devices to higher
light output and higher operation temperatures. For instance, the efficiency can
be raised by adapting better package design or by using a more suitable type of
phosphor. Philips Lumileds' patented conformal coating process addresses the
issue of varying phosphor thickness, giving the white LEDs a more homogeneous
white light. With development ongoing, the
efficiency of phosphor based LEDs generally rises with each new product
announcement.
The
phosphor based white LEDs encapsulate InGaN blue LEDs inside phosphor coated
epoxy. A common yellow phosphor material is cerium-doped yttrium aluminium
garnet (Ce3+:YAG).
White
LEDs can also be made by coating near ultraviolet (NUV)
emitting LEDs with a mixture of high efficiency europium-based red and blue
emitting phosphors plus green emitting copper and aluminium doped zinc sulfide
(ZnS:Cu, Al). This is a method analogous to the way fluorescent
lamps work. This method is less efficient
than the blue LED with YAG:Ce phosphor, as the Stokes shift is
larger, so more energy is converted to heat, but yields light with better spectral
characteristics, which render color better. Due to the higher radiative output
of the ultraviolet LEDs than of the blue ones, both methods offer comparable
brightness. A concern is that UV light may leak from a malfunctioning light
source and cause harm to human eyes or skin.
7.6.4 Quantum dot LED
A new
method developed by Michael Bowers, a graduate student at Vanderbilt University in
Nashville, involves coating a blue LED with quantum
dots that glow white in response to the blue
light from the LED. This method emits a warm, yellowish-white light similar to
that made by incandescent
bulbs.
Quantum
dots (QD) are semiconductor nanocrystals
that possess unique optical properties.] Their
emission color can be tuned from the visible throughout the infrared spectrum.
This allows quantum dot LEDs to create almost any color on the CIE diagram.
This provides more color options and better color rendering than white LEDs.
Quantum dot LEDs are available in the same package types as traditional phosphor based
LEDs.
In
September 2009 Nanoco Group
announced that it has signed a joint development agreement with a major
Japanese electronics company under which it will design and develop quantum
dots for use in light emitting diodes (LEDs) in liquid crystal display (LCD)
televisions.
The
major difficulty in using quantum dots based LEDs is the insufficient stability
of QDs under prolonged irradiation. In February 2011 scientists at PlasmaChem
GmbH could synthesize quantum dots for LED applications and build a light
converter on their basis, which could efficiently convert light from blue to
any other color for many hundred hours.] Such
QDs can be used to emit visible or near infrared light of any wavelength being
excited by light with a shorter wavelength.
7.7 Advantages of LED
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.
§ 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.
§ Cool light: In
contrast to most light sources, LEDs radiate very little heat in the form of IR that
can cause damage to sensitive objects or fabrics. Wasted energy is dispersed as
heat through the base of the LED.
§ Slow failure: LEDs
mostly fail by dimming over time, rather than the abrupt failure of
incandescent bulbs.
§ Lifetime: LEDs
can have a relatively long useful life. One report estimates 35,000 to 50,000
hours of useful life, though time to complete failure may be longer.Fluorescent
tubes typically are rated at about 10,000 to 15,000 hours, depending partly on
the conditions of use, and incandescent light bulbs at 1,000–2,000 hours.
§ Shock resistance: LEDs,
being solid state components, are difficult to damage with external shock,
unlike fluorescent and incandescent bulbs which are fragile.
§ Focus: The
solid package of the LED can be designed to focus its light. Incandescent and
fluorescent sources often require an external reflector to collect light and
direct it in a usable manner.
7.8 Disadvantages of LED
§ 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. This is especially important in automotive,
medical, and military uses where devices must operate over a wide range of
temperatures, and need low failure rates.
§ 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. The spike at 460 nm and dip at
500 nm can cause the color of objects to be perceived
differently under cool-white LED illumination than
sunlight or incandescent sources, due to metamerism, red
surfaces being rendered particularly badly by typical phosphor based cool-white
LEDs. However, the color rendering properties of common fluorescent lamps are
often inferior to what is now available in state-of-art white LEDs.
§ Area light source: LEDs
do not approximate a “point source” of light, but rather a lambertian distribution.
So LEDs are difficult to apply to uses needing a spherical light field. LEDs
cannot provide divergence below a few degrees. In contrast, lasers can emit
beams with divergences of 0.2 degrees or less.
§ Blue hazard: There
is a concern that blue
LEDs and cool-white LEDs are now
capable of exceeding safe limits of the so-called blue-light
hazard as defined in eye safety specifications
such as ANSI/IESNA RP-27.1–05: Recommended Practice for Photobiological Safety
for Lamp and Lamp Systems.
§ Electrical Polarity: Unlike incandescent light
bulbs, which illuminate regardless of the electrical polarity, LEDs will only light
with correct electrical polarity.
§ Blue pollution: Because
cool-white
LEDs (i.e., LEDs with high color temperature)
emit proportionally more blue light than conventional outdoor light sources
such as high-pressure sodium
vapor lamps, the strong wavelength dependence of Rayleigh scattering means
that cool-white LEDs can cause more light pollution than
other light sources. The International
Dark-Sky Association discourages
using white light sources with correlated color temperature above 3,000 K.
The
next chapter 8 deals with Preamplifier Circuits.
CHAPTER 8
PREAMPLIFIER CIRCUIT
8.1
INTRODUCTION
A preamplifier (preamp), or control amplifier, is an electronic amplifier that prepares an electronic signal for further amplification or processing. The
preamplifier circuitry may or may not be housed separately from the device for
which a signal is being prepared.
In general, the function of a preamplifier is to amplify a
low-level signal to line-level.
A list of common low-level signal sources would include a pickup, microphone, turntable or
other transducers. Equalization and tone
control may also be applied.
In a home audio
system, the term 'preamplifier' may sometimes be used to describe equipment
which merely switches between
different line level sources
and applies avolume control, so that no actual amplification may be
involved. In an audio system, the second amplifier is typically a power
amplifier (power amp). The preamplifier providesvoltage gain
(e.g. from 10 millivolts to 1 volt) but no significant current gain.
The power amplifier provides the higher current necessary to drive loudspeakers.
Preamplifiers may be:
§ incorporated
into the housing or chassis of the amplifier they feed
§ in a
separate housing
8.2
CIRCUIT DIAGRAM
Fig8.1-This figure shows Preamplifier circuit.
8.3
Explanation
DESCRIPTION
The TBA820M
is a monolithic integrated audio amplifier in a 8 lead dual in-line plastic
package. It is intended for use as low frequency class B power amplifier with
wide range of supply voltage: 3 to 16V, in portable radios, cassette recorders
and players etc. Main features are: minimum working supply voltage of 3V, low
quiescent current, low number of external components, good ripple rejection, no
cross-over distortion, low power dissipation. Output power: Po = 2W at 12V/8Ω,
1.6W at 9V/4Ω and 1.2W at 9V/8Ω.
8.4
Discriptive view on PCB
Fig 8.2-This figure shows view of PCB.
The next chapter 9 deals with MEMS.
CHAPTER
9
MEMS
9.1 INTRODUCTION
Microelectromechanical
systems (MEMS) (also written as micro-electro-mechanical, MicroElectroMechanical or microelectronic and microelectromechanical systems)
is the technology of very small mechanical devices driven by electricity; it
merges at the nano-scale into nanoelectromechanical
systems (NEMS) and nanotechnology. MEMS are
also referred to as micromachines (in
Japan), or Micro
Systems Technology - MST (in
Europe).
MEMS are separate and distinct from the hypothetical
vision of molecular
nanotechnology or molecular electronics.
MEMS are made up of components between 1 to 100 micrometres in size (i.e. 0.001
to 0.1 mm) and MEMS devices generally range in size from 20 micrometres
(20 millionths of a metre) to a millimetre. They usually consist of a central
unit that processes data, the microprocessor and several components that
interact with the outside such as microsensors. At these size scales, the
standard constructs of classical physics are
not always useful. Because of the large surface area to volume ratio of MEMS,
surface effects such as electrostatics and wettingdominate volume effects
such as inertia or
thermal mass.
The potential of very small machines was appreciated
before the technology existed that could make them—see, for example, Richard Feynman's
famous 1959 lectureThere's
Plenty of Room at the Bottom. MEMS became practical once they could be
fabricated using modified semiconductor
device fabrication technologies, normally used to make electronics. These include
molding and plating, wet etching (KOH, TMAH) and dry etching (RIE and
DRIE), electro discharge machining (EDM),
and other technologies capable of manufacturing small devices. An early example
of a MEMS device is the resonistor – an electromechanical monolithic resonator.
Fig 9.1-MEMS
device.
9.2
Materials for MEMS manufacturing
9.2.1
Silicon
Silicon is
the material used to create most integrated circuits used
in consumer electronics in the modern world. The economies of scale,
ready availability of cheap high-quality materials and ability to incorporate
electronic functionality make silicon attractive for a wide variety of MEMS
applications. Silicon also has significant advantages engendered through its
material properties. In single crystal form, silicon is an almost perfect Hookean material,
meaning that when it is flexed there is virtually no hysteresisand hence almost
no energy dissipation. As well as making for highly repeatable motion, this
also makes silicon very reliable as it suffers very little fatigue and can
have service lifetimes in the range of billions to trillions of
cycles without breaking. The basic techniques for producing all silicon based
MEMS devices are deposition of
material layers, patterning of these layers by photolithography and
then etching to produce the required shapes.
9.2.2
Polymers
Even
though the electronics industry provides an economy of scale for the silicon
industry, crystalline silicon is still a complex and relatively expensive
material to produce. Polymers on the other hand can be produced in huge
volumes, with a great variety of material characteristics. MEMS devices can be
made from polymers by processes such as injection molding, embossing or stereolithography and
are especially well suited to microfluidic applications
such as disposable blood testing cartridges.
9.2.3
Metals
Metals
can also be used to create MEMS elements. While metals do not have some of the
advantages displayed by silicon in terms of mechanical properties, when used
within their limitations, metals can exhibit very high degrees of reliability.
Metals can be deposited by electroplating, evaporation,
and sputtering processes.
Commonly used metals include gold, nickel, aluminium, copper, chromium, titanium, tungsten, platinum, and silver.
9.3
Basic process
9.3.1 Deposition processes
One of the basic building blocks
in MEMS processing is the ability to deposit thin films of material with a
thickness anywhere between a few nanometres to about 100 micrometres.
9.3.2 Physical
deposition
There are two types of physical deposition processes.
1.Physical vapor
deposition (PVD)
Physical vapor deposition consists of a process in which
a material is removed from a target, and deposited on a surface. Techniques to
do this include the process ofsputtering,
in which an ion beam liberates atoms from a target, allowing them to move
through the intervening space and deposit on the desired substrate.
2. Evaporation
(deposition), in which a material is evaporated from a target using either
heat (thermal evaporation) or an electron beam (e-beam evaporation) in a vacuum
system.
9.3.3 Chemical deposition
Chemical
deposition techniques include chemical vapor deposition ("CVD"), in
which a stream of source gas reacts on the substrate to grow the material
desired. This can be further divided into categories depending on the details
of the technique, for example, LPCVD (Low
Pressure chemical vapor deposition) and PECVD (Plasma
Enhanced chemical vapor deposition).
Oxide films can also be grown by the technique of thermal oxidation, in
which the (typically silicon) wafer is exposed to oxygen and/or steam, to grow
a thin surface layer ofsilicon
dioxide.
9.3.4 Patterning
Patterning in MEMS is the transfer of a pattern into a
material.
9.3.5 Lithography
Lithography
in MEMS context is typically the transfer of a pattern into a photosensitive
material by selective exposure to a radiation source such as light. A
photosensitive material is a material that experiences a change in its physical
properties when exposed to a radiation source. If a photosensitive material is
selectively exposed to radiation (e.g. by masking some of the radiation) the
pattern of the radiation on the material is transferred to the material
exposed, as the properties of the exposed and unexposed regions differs.
This
exposed region can then be removed or treated providing a mask for the
underlying substrate. Photolithography is
typically used with metal or other thin film deposition, wet and dry etching.
Electron
beam lithography (often abbreviated as e-beam lithography) is the practice of
scanning a beam of electrons in
a patterned fashion across a surface covered with a film (called the resist) ("exposing"
the resist) and of selectively removing either exposed or non-exposed regions
of the resist ("developing"). The purpose, as withphotolithography, is
to create very small structures in the resist that can subsequently be
transferred to the substrate material, often by etching. It was developed for
manufacturing integrated circuits, and is also used for
creating nanotechnology architectures.
The
primary advantage of electron beam lithography is that it is one of the ways to
beat the diffraction
limit of light and make features in the nanometer regime.
This form of maskless
lithography has found wide usage in photomask-making used in photolithography,
low-volume production of semiconductor components, and research &
development.
The key
limitation of electron beam lithography is throughput, i.e., the very long time
it takes to expose an entire silicon wafer or glass substrate. A long exposure
time leaves the user vulnerable to beam drift or instability which may occur
during the exposure. Also, the turn-around time for reworking or re-design is
lengthened unnecessarily if the pattern is not being changed the second time.
9.4 MEMS manufacturing process
9.4.1 Bulk
micromachining
Bulk
micromachining is the oldest paradigm of silicon based MEMS. The whole
thickness of a silicon wafer is used for building the micro-mechanical
structures Silicon is machined using various etching
processes. Anodic bonding of
glass plates or additional silicon wafers is used for adding features in the
third dimension and for hermetic encapsulation. Bulk micromachining has been
essential in enabling high performance pressure
sensors and accelerometers that
have changed the shape of the sensor industry in the 80's and 90's.
9.4.2
SURFACE MICROMACHINING
Surface
micromachining uses layers deposited on the surface of a substrate as the
structural materials, rather than using the substrate itself. Surface
micromachining was created in the late 1980s to render micromachining of
silicon more compatible with planar integrated circuit technology, with the
goal of combining MEMS and integrated circuits on
the same silicon wafer. The original surface micromachining concept was based
on thin polycrystalline silicon layers patterned as movable mechanical structures
and released by sacrificial etching of the underlying oxide layer. Interdigital
comb electrodes were used to produce in-plane forces and to detect in-plane
movement capacitively. This MEMS paradigm has enabled the manufacturing of low
cost accelerometers for
e.g. automotive air-bag systems and other applications where low performance
and/or high g-ranges are sufficient. Analog Devices have
pioneered the industrialization of surface micromachining and have realized the
co-integration of MEMS and integrated circuits.
9.4.3
High aspect ratio
Both
bulk and surface silicon micromachining are used in the industrial production
of sensors, ink-jet nozzles, and other devices. But in many cases the
distinction between these two has diminished. A new etching technology, deep reactive-ion
etching, has made it possible to combine good performance typical of bulk micromachining with
comb structures and in-plane operation typical of surface
micromachining. While it is common in surface micromachining to have
structural layer thickness in the range of 2 µm, in HAR silicon
micromachining the thickness can be from 10 to 100 µm. The materials
commonly used in HAR silicon micromachining are thick polycrystalline silicon,
known as epi-poly, and bonded silicon-on-insulator (SOI) wafers although
processes for bulk silicon wafer also have been created (SCREAM). Bonding a
second wafer by glass frit bonding, anodic bonding or alloy bonding is used to
protect the MEMS structures. Integrated circuits are typically not combined
with HAR silicon micromachining. The consensus of the industry at the moment
seems to be that the flexibility and reduced process complexity obtained by
having the two functions separated far outweighs the small penalty in
packaging. A comparison of different high-aspect-ratio microstructure
technologies can be found in the HARMST article.
A
forgotten history regarding surface micromachining revolved around the choice
of polysilicon A or B. Fine grained (<300A grain size, US4897360), post
strain annealed pure polysilicon was advocated by Prof Henry Guckel (U.
Wisconsin); while a larger grain, doped stress controlled polysilicon was
advocated by the UC Berkeley group.
9.5 MEMS devices
9.5.1 MEMS microphone
Fig
9.2-This figure shows MEMS microphone.
A microphone (colloquially
called a mic or mike;
both pronounced /ˈmaɪk/) is an acoustic-to-electric transducer or sensor that
convertssound into
an electrical
signal. In 1876, Emile Berliner invented
the first microphone used as a telephone voice transmitter. Microphones are
used in many applications such as telephones, tape
recorders, karaoke systems, hearing
aids, motion
picture production, live and recorded audio engineering, FRS radios, megaphones,
in radio and television broadcasting
and in computers for recording voice, speech recognition, VoIP,
and for non-acoustic purposes such as ultrasonic checking or knock sensors.
Most
microphones today use electromagnetic
induction (dynamic microphone), capacitance
change (condenser microphone), piezoelectricgeneration,
or light modulation to produce an electrical voltage signal from mechanical
vibration.
The MEMS (MicroElectrical-Mechanical System) microphone is also
called a microphone chip or silicon microphone. The pressure-sensitive
diaphragm is etched directly into a silicon chip by MEMS techniques, and is
usually accompanied with integrated preamplifier. Most MEMS microphones are
variants of the condenser microphone design. Often MEMS microphones have built
in analog-to-digital converter (ADC) circuits on the same CMOS chip making the
chip a digital microphone and so more readily integrated with modern digital
products. Major manufacturers producing MEMS silicon microphones are Wolfson
Microelectronics (WM7xxx), Analog Devices, Akustica (AKU200x), Infineon (SMM310
product), Knowles Electronics, Memstech (MSMx), NXP Semiconductors, Sonion
MEMS, AAC Acoustic Technologiesand Omron.
9.5.2 MEMS accelerometer
An accelerometer is a device that measures the proper acceleration of the device. This is not necessarily the same as the coordinate acceleration (change of
velocity of the device in space), but is rather the type of acceleration
associated with the phenomenon of weight experienced by a test mass that resides in the frame of reference of the accelerometer device. For an example of where
these types of acceleration differ, an accelerometer will measure a value when
sitting on the ground, because masses there have weights, even though they do
not change velocity. However, an accelerometer in gravitational free fall toward the center of the Earth will measure a value of
zero because, even though its speed is increasing, it is in an inertial frame of reference, in which it is weightless
Fig9.3-MEMS accelerometer
Fig9.4-This figure shows MEMS accelerometer overview.
9.5.3 MEMS gyroscope
Fig 9.5-This figure shows MEMS gyroscope.
A vibrating
structure gyroscope is a
type of gyroscope that
functions much like the halteres of
an insect. The underlying physical principle is that a vibrating object tends
to continue vibrating in the same plane as its support rotates. In the
engineering literature, this type of device is also known as a Coriolis vibratory gyro because
as the plane of oscillation is rotated, the response detected by the transducer
results from the Coriolis term in its equations of motion ("Coriolis
force").
Vibrating structure gyroscopes are simpler and cheaper
than conventional rotating gyroscopes of similar accuracy. Miniaturized devices
using this principle are a relatively inexpensive type of attitude indicator.
Inexpensive (as of 2010, approximately US$5 per part in
quantity) vibrating structure gyroscopes manufactured with MEMS technology
have become widely available. These are packaged similarly
to other integrated circuits and
may provide either analog or digital outputs. In many cases, a single part
includes gyroscopic sensors for multiple axes. Some parts incorporate both a
gyroscope and an accelerometer, in which
case the output has six full degrees of freedom. InvenSense, Seiko Epson,STMicroelectronics, Kionix, and Analog Devices are
major manufacturers.
Internally, MEMS gyroscopes use lithographically
constructed versions of one or more of the mechanisms outlined above (tuning
forks, vibrating wheels, or resonant solids of various designs) .
9.6 Applications of MEMS
Fig 9.6-This figure shows applications of MEMS.
9.6.1 Biotechnology
MEMS and Nanotechnology is enabling new discoveries in
science and engineering such as the Polymerase Chain Reaction (PCR)
microsystems for DNA amplification and identification, enzyme linked
immunosorbent assay (ELISA), capillary electrophoresis, electroporation,
micromachined Scanning Tunneling Microscopes (STMs), biochips for detection of
hazardous chemical and biological agents, and microsystems for high-throughput
drug screening and selection.
9.6.2 Medicine
There are a wide
variety of applications for MEMS in medicine. The first and by far the most
successful application of MEMS in medicine (at least in terms of number of
devices and market size) are MEMS pressure sensors, which have been in use for
several decades. The market for these pressure sensors is extremely diverse and
highly fragmented, with a few high-volume markets and many lower volume ones.
Some of the applications of MEMS pressure sensors in medicine include:
·
The
largest market for MEMS pressure sensors in the medical sector is the
disposable sensor used to monitor blood pressure in IV lines of patients in
intensive care. These devices were first introduced in the early 1980’s. They
replaced other technologies that cost over $500 and which had a substantial
recurring cost since they had to be sterilized and recalibrated after each use.
MEMS disposable pressure sensors are delivered pre-calibrated in a sterilized
package from the factory at a cost of around $10.
·
MEMS
pressure sensors are used to measure intrauterine pressure during birth. The
device is housed in a catheter that is placed between the baby's head and the
uterine wall. During delivery, the baby's blood pressure is monitored for
problems during the mother's contractions.
·
MEMS
pressure sensors are used in hospitals and ambulances as monitors of a
patient’s vital signs, specifically the patient’s blood pressure and
respiration.
·
The
MEMS pressure sensors in respiratory monitoring are used in ventilators to
monitor the patient’s breathing.
·
MEMS
pressure sensors are used for eye surgery to measure and control the vacuum
level used to remove fluid from the eye, which is cleaned of debris and
replaced back into the eye during surgery
·
Special
hospital beds for burn victims that employ inflatable mattresses use MEMS
pressure sensors to regulate the pressure inside a series of individual
inflatable chambers in the mattress. Sections of the mattress can be inflated
as needed to reduce pain as well as improve patient healing.
·
Physician’s
office and hospital blood analyzers employ MEMS pressure sensors as barometric
pressure correction for the analysis of concentrations of O2, CO2, calcium,
potassium, and glucose in a patient's blood.
·
MEMS
pressure sensors are used in inhalers to monitor the patient’s breathing cycle
and release the medication at the proper time in the breathing cycle for
optimal effect.
·
MEMS
pressure sensors are used in kidney dialysis to monitor the inlet and outlet
pressures of blood and the dialysis solution and to regulate the flow rates
during the procedure.
·
MEMS
pressure sensors are used in drug infusion pumps of many types to monitor the
flow rate and detect for obstructions and blockages that indicate that the drug
is not being properly delivered to the patient.
The contribution to
patient care for all of these applications has been enormous. More recently,
MEMS pressure sensors have been developed and are being marketed that have
wireless interrogation capability. These sensors can be implanted into a human
body and the pressure can be measured using a remotely scanned wand. Another
application are MEMS inertial sensors, specifically accelerometers and rate
sensors which are being used as activity sensors. Perhaps the foremost
application of inertial sensors in medicine is in cardiac pacemakers wherein
they are used to help determine the optimum pacing rate for the patient based on
their activity level. MEMS devices are also starting to be employed in drug
delivery devices, for both ambulatory and implantable applications. MEMS
electrodes are also being used in neuro-signal detection and neuro-stimulation
applications. A variety of biological and chemical MEMS sensors for invasive
and non-invasive uses are beginning to be marketed. Lab-on-a-chip and
miniaturized biochemical analytical instruments are being marketed as well.
9.6.3 Communication
High frequency circuits are benefiting considerably from
the advent of RF-MEMS technology. Electrical components such as inductors and
tunable capacitors can be improved significantly compared to their integrated
counterparts if they are made using MEMS and Nanotechnology. With the integration
of such components, the performance of communication circuits will improve,
while the total circuit area, power consumption and cost will be reduced. In
addition, the mechanical switch, as developed by several research groups, is a
key component with huge potential in various RF and microwave circuits. The
demonstrated samples of mechanical switches have quality factors much higher
than anything previously available. Another successful application of RF-MEMS
is in resonators as mechanical filters for communication circuits.
9.6.4
Inertial sensing
MEMS
inertial sensors, specifically accelerometers and gyroscopes, are quickly
gaining market acceptance. For example, MEMS accelerometers have displaced
conventional accelerometers for crash air-bag deployment systems in
automobiles. The previous technology approach used several bulky accelerometers
made of discrete components mounted in the front of the car with separate
electronics near the air-bag and cost more than $50 per device. MEMS technology
has made it possible to integrate the accelerometer and electronics onto a
single silicon chip at a cost of only a few dollars. These MEMS accelerometers
are much smaller, more functional, lighter, more reliable, and are produced for
a fraction of the cost of the conventional macroscale accelerometer elements.
More recently, MEMS gyroscopes (i.e., rate sensors) have been developed for
both automobile and consumer electronics applications. MEMS inertial sensors
are now being used in every car sold as well as notable customer electronic
handhelds such as Apple iPhones and the Nintendo Wii.
9.7 How it is a better technology?
Table 1 –This table shows increase use of MEMS in recent
years.
1.Size-It requires very
less space as compared to other microphones.
2.Cost-It is cheaper than
other devices
3.Based on real time
system.
The next chapter 10 deals
with Relays.
CHAPTER 10
RELAYS
10.1 INTRODUCTION
A
relay is a device that allows you to control a high-current electrical load
with a low-current electrical 'signal'. they are usually electro-magnetic, but
are also available in solid-state forms. they can be used with a switch (to
allow control of a high-current load with a small switch) or they can be hooked
up to a switched power source in the car like the ignition or accessory power
circuits (to allow power to be switched on/off automatically with the ignition
key).
Fig 10.1-This figure shows Relay
device.
10.2
Importance of relay
When hooking anything up to a
car's factory wiring, it's important to remember that factory wires are
designed to carry the load of only the factory installed components. they are
not 'general use' power circuits like the power outlets in your house. for
example, the ignition (IGN) circuit is designed to power the car's ignition
system and nothing else. hooking up a high-current device to this circuit can
create a fire hazard. by using a relay, you can use the IGN circuit to control
a high-current device without directly powering it from the IGN circuit itself.
Relays
allow one circuit to switch a second circuit which can be completely separate
from the first. For example a low voltage battery circuit can use a relay to
switch a 230V AC mains circuit.
Relays have 2 circuits: A control circuit (green)& load circuit(red)
A control circuit has a small control coil.
A load circuit has a switch.
The coil controls the operation of the switch.
Fig 10.2-This figure shows how relay works.
·
Relay energized (ON):-
Current
flowing through the control circuit coil(pins 1 and 2 ) creates a small
magnetic field which causes the switch to close, pins 5 and 3(NO) .the
switch,which is part of the load circuit,is used to control an electrical
circuit that may connect to it.current now flows through pins5 and 3,when the
relay energized.
·
Relay de-energized (OFF):-
When the
current stops flowing through the control circuit, pins 1 and 2 ,the relay
becomes de-energized. Without the magnetic field, the switch opens and pin 5 is
connected to pin 4(NO) .the relay is now
OFF.
Continuity check:-
If the relay is not labeled, Use an ohmmeter and check to
see which pins are connected to each other.
You will get an ohm value of approximately 50to 120 ohms
between two pins. This is the control circuit.
You will find continuity between two pins that pin is
nothing but NC.
And remaining pin is NO.
Here N0 and NC means normally open and normally closed
respectively.
The next chapter 11 deals with DTMF.
CHAPTER 11
DTMF
11.1
INTRODUCTION
The CAMD CM8870/70C provides
full DTMF receiver capability by integrating both the band-split filter and
digital decoder functions into a single 18-pin DIP, SOIC, or 20-pin PLCC
package. The CM8870/70C is manufactured using state-of-the-art CMOS process
technology for low power consumption (35mW, MAX) and precise data handling. The
filter section uses a switched capacitor technique for both high and low group
filters and dial tone rejection. The CM8870/70C decoder uses digital counting
techniques for the detection and decoding of all 16 DTMF tone pairs into a
4-bit code. This DTMF receiver minimizes external component count by providing
an on-chip differential input amplifier, clock generator, and a latched
three-state interface bus. The on-chip clock generator requires only a low cost
TV crystal or ceramic resonator as an external component.
Fig11.1- This figure shows DTMF circuit diagram.
11.2 Features of DTMF
• Full DTMF receiver
• Less than 35mW power consumption
• Industrial temperature range
• Uses quartz crystal or ceramic resonators
• Adjustable acquisition and release times
• 18-pin DIP, 18-pin DIP EIAJ, 18-pin SOIC, 20-pin
PLCC
• CM8870C
— Power down mode
— Inhibit mode
— Buffered OSC3 output (PLCC package only)
• CM8870C is fully compatible with CM8870 for 18-pin
devices by grounding pins 5 and 6
The next chapter 12 deals with 3 G.
Chapter 12
3G
12.1
INTRODUCTION
3G or 3rd generation mobile telecommunications,
is a generation of standards for mobile phones and mobile telecommunications services fulfilling the International Mobile
Telecommunications-2000 (IMT — 2000) specifications by the International Telecommunication Union.[1] Application services include wide-area wireless
voice telephone, mobile Internet access, video calls and mobile TV, all in a mobile environment. To meet the IMT-2000
standards, a system is required to provide peak data rates of at least
200 kbit/s. Recent 3G
releases, often denoted 3.5G and3.75G, also provide mobile broadband access of several Mbit/s to smartphones and mobile modems in laptop computers.
The following
standards are typically branded 3G:
§ the UMTS system, first offered in 2001, standardized by 3GPP, used primarily in Europe, Japan, China (however with a
different radio interface) and other regions predominated by GSM 2G system infrastructure. The cell phones are typically
UMTS and GSM hybrids. Several radio interfaces are offered, sharing the same
infrastructure:
§ The latest UMTS release, HSPA+, can provide peak data rates up to 56 Mbit/s in the
downlink in theory (28 Mbit/s in existing services) and 22 Mbit/s in the
uplink.
§ the CDMA2000 system, first offered in 2002, standardized by 3GPP2, used especially in North America and South Korea, sharing
infrastructure with the IS-95 2G standard. The cell
phones are typically CDMA2000 and IS-95 hybrids. The latest release EVDO Rev B offers peak rates of 14.7 Mbit/s downstreams.
12.2
FEATURES
·
Data
rates
ITU has not
provided a clear definition of the data rate users can expect from 3G equipment
or providers. Thus users sold 3G service may not be able to point to a standard
and say that the rates it specifies are not being met. While stating in
commentary that "it is expected that IMT-2000 will provide higher
transmission rates: a minimum data rate of 2 Mbit/s for stationary or walking
users, and 384 kbit/s in a moving vehicle,"[18] the ITU does not actually clearly specify minimum or
average rates or what modes of the interfaces qualify as 3G, so various rates
are sold as 3G intended to meet customers expectations of broadband data.
·
Security
3G networks offer
greater security than their 2G predecessors. By allowing the UE (User
Equipment) to authenticate the network it is attaching to, the user can be sure
the network is the intended one and not an impersonator. 3G networks use
the KASUMI block crypto instead of the older A5/1 stream cipher. However, a number of serious weaknesses in the KASUMI
cipher have been identified.[19]
In addition to
the 3G network infrastructure security, end-to-end security is offered when
application frameworks such as IMS are accessed, although this is not strictly a 3G
property.
· APPLICATIONS
The bandwidth and location
information available to 3G devices gives rise to applications not previously
available to mobile phone users. Some of the applications are:
§ Mobile TV – a provider redirects a TV channel directly to the
subscriber's phone where it can be watched.
§ Video on demand – a provider sends a
movie to the subscriber's phone.
§ Video conferencing – subscribers can
see as well as talk to each other.
§ Tele-medicine – a medical provider monitors or provides advice to the
potentially isolated subscriber.
§ Location-based services – a provider sends
localized weather or traffic conditions to the phone, or the phone allows the
subscriber to find nearby businesses or friends.
The next chapter 13 deals with Implementation and Result.
Chapter 13
Implementation and Result
Implementation and Result
Basically this depicts the way we
have implemented our project .
Fig 13.1 shows the circuit diagram
of our project .It contains the following components:
1.Microcontroller (AT89c52)
2.Relay (12v and 6V)
3.DTMF (CM8870)
4.Sink Driver (ULN2003)
Fig 13.1- The figure is the circuit diagram of
our project.
13.1 Explanation
The diagram which has shown is an
overview of the circuit diagram of our project. Basically we are controlling
our car through our mobile .As we press button 2 for forward move the frequency of keypad tone is detected by
dtmf and given to microcontroller to read that instruction through Port 1 from
Pin number 1 to 4 .Through microcontroller the instruction is given to relays
which switch low current device to high current device and makes our car to
run. To maintain the relays we used driver chip ULN2003.
13.2 MEMS
Basically we used MEMS microphone
which eliminates all the other noises from environment and gives 60 percent
more efficiency than other microphone. The cost of this microphone is very less
compared to other microphones and more compatible as compared to others.
Pin diagram of MEMS:
Fig 13.2-This figure shows pin
diagram of MEMS.
DESCRIPTION OF PIN
Table 2- This figure shows pin
diagram of MEMS.
BLOCK DIAGRAM OF MEMS
The figure shows the block diagram
of MEMS.
Fig
13.3 – This shows the block diagram of MEMS.
As we can see in this two ground
pins are there and in this filter is in built which provides noise immunity for
practical implementation in Real Time environment. Basically this microphone
takes the input from sensors and gives the output through actuators . MEMS
microphone is having an internal
bias of 1.2v .Basically the MEMS
are formed through batch formation technique. It is formed on basis of
piezoelectric effect that means charge will accumulate if we put pressure on
the chip.
MEMS Dimension
Fig 13.4-This figure shows package
dimension of MEMS .
13.3 Design of power supply
Basically we used to take 230v
alternating current from supply and then given to step down transformer and
than to smoothing capacitor and than to 7805 voltage regulator which gives
output of 5v.
Fig 13.5-This shows the power
supply circuit diagram.
You will need:
1. Step down transformer [12V]
2. Four silicon diodes [1N4007]
3. Resistor [47?]
4. Capacitors [2 x 220µF, 0.3µF and
0.1µF]
5.
Three terminal voltage regulator IC [LM7805]
6. A small general propose PCB,
some wires, and a suitable output port (I use a
audio connector)
The next chapter 14 deals with Embedded C programming.
CHAPTER 14
EMBEDDED C PROGRAMMING
14.1 INTRODUCTION
Compilers produce hex files
that we download into the ROM of the microcontroller. The size of the hex file
produced by the compiler is one of the main concern of microcontroller
programmers, for two reasons:
1.Microcontrollers have limited on chip ROM.
2.The code space
for the 8052 is limited to 128KB.
How does the choice of programming language affect the
compiler programming size??
While assembly language programming produces a hex file
that is much smaller than C –programming ,on the other hand it is less time
consuming and much easier to write ,but the hex file size produced is much
larger than if used assembly language. The following are some of the major
reasons for writing programme in C instead of assembly:
1.It is easier and less time consuming to write in C than assembly.
2.It is easier to modify and update.
3.You can use code available in function libraries.
4.C-code is portable to other microcontrollers with
little or no modifications.
14.2 FLOWCHART
CHAPTER 1
INTRODUCTION
When
encountered something, someone or some place we use our five natural senses to
perceive information about it, that information helps us make decisions and
choose the right decisions to take. But arguably the most useful information
that can helps us to make the right decision is not naturally perceivable with
our five senses, namely the data, information and knowledge that mankind has
accumulated about everything and which is increasingly all available online.
Although the miniaturization of computing devices allows us to the digital
world, there is no link between our digital devices and our interactions with
the physical world. Information is confined traditionally on paper or digitally
on a screen. Sixthsense bridges this gap, bringing intangible, digital
information out into the tangible world and allowing us to interact with this
information via natural hand gestures. ‘Sixthsense’ frees information from its
confines by seamlessly integrating it with reality and thus making the entire
world your computer.
Sixth
sense is the interpretation between the real world and digital world. Things
that we do in the real time is interpreted by the system (computer) and
processing done according to the need.
CHAPTER 2
FUNDAMENTALS OF IMAGE
Image Processing is technique by which we can
process any image to extract the real information i.e. useful information from
the image. Sometimes we require some specific part of the image to process and
for it we have to select that portion only. This technique of selecting useful
portion is called cropping.
2.1 Pixel
In digital imaging, a pixel, or pel, (picture element) is a single point in
a raster image, or the smallest addressable screen element in a display device;
it is the smallest unit of picture that can be represented or controlled. Each
pixel has its own address. The address of a pixel corresponds to its
coordinates. Pixels are normally arranged in a two-dimensional grid, and are
often represented using dots or squares. Each pixel is a sample of an original
image; more samples typically provide more accurate representations of the
original. The intensity of each pixel is variable. In color image systems, a
color is typically represented by three or four component intensities such as red,
green, and blue, or cyan, magenta, yellow, and black.
In some contexts (such as descriptions of camera
sensors), the term pixel is
used to refer to a single scalar element of a multi-component representation
(more precisely called a photo site
in the camera sensor context, although the neologism sensel is also sometimes used to describe the elements of a
digital camera's sensor), while in others the term may refer to the entire set
of such component intensities for a spatial position. In color systems that use
chroma sub sampling, the multi-component concept of a pixel can become
difficult to apply, since the intensity measures for the different color
components correspond to different spatial areas.
Fig 2.1 Pixels of
an Image
.2.2 Image
processing toolbox
An image may be defined as a two dimensional
function f(x, y), where x and y are spatial coordinates and the amplitude of f
at any pair of coordinates (x, y) is called the intensity or gray level of the
image at that point. Image processing is type of signal processing in which we have image as an input and
we process it by applying some operations on the selected pixels to get some
useful information out of it. In image processing we can improve the image to
appear it better i.e. in context of our information extraction from given
image. Image processing is of many types like digital image processing, optical
image processing and analog signal processing. In image processing technique we
consider any image as multi dimensional matrices depending on the format of the
image. The task that can be performed by image processing is color correction,
compression decompression of the image, image recognition and image cropping.
Two broad categories in image processing includes the modification in quality
of picture like color, sharpness etc. and other is resizing like cropping.
In
first type of processing we need to modify the amplitude level and in the
second category type processing we select or reject some pixels value which are
not desired. Cropping an image means creating a new image from a part of an
original image. It is real important task as it may be needed to extract some
specific part of an image or to change aspect ratio of an image, as aspect
ratio is major concern in film making. It is generally used to remove the
unwanted or irrelevant detail from the photo.
2.3 Cropping shapes
We
generally use rectangular cropping due to ease of its implementation. But what
if we have to remove red eye and eye use to be circularly crop, and in another
example if we have to use face recognition and we have to scan only retina of
the eye which is also in circular form so circular crop is equally important as
well. So that the triangular and square cropping. Different shapes in which we
can crop the image is given as
2.3.1
Rectangular Crop:
It
is easiest to crop image in rectangular form because we have to just select two
coordinates on the image and using MATLAB we decide other two coordinates and
the image is cropped in rectangular format. Rectangular crop is as shown in
fig. 2.4.
2.3.2 Circular
crop:
In
this type of cropping we select center of the circular form in which we have to
crop the image, then we select other point on the image to decide the cropped
image radius. In implementation of circular crop we use locus of the circle to
crop the image in circular form. It is the most useful shape to crop any image
in this form. The locus use for cropping image in circular form is given by
(x
- a)2+ (y - b)2= R2
Where
h and k are the x- and y-coordinates of the center of the circle and r is the
radius. Circular crop is as shown in fig. 2.3.
2.3.3 Square
Crop:
To
crop any image in square form we have to define two points on the image for
corner points and then we define points by this coordinate such that x=y=d,
where d is some constant.
2.3.4 Triangular
Crop:
Because
triangular shape doesn’t regular locus point, we have to use some other
technique to crop image in triangular form. For cropping image in triangular
form we check pixels of the image, in which side of the lines of the triangle.
Triangular cropping is as shown in fig.2.5
Fig 2.2:
Original Image
Fig 2.3
Circular Crop
Fig 2.4 Rectangular Crop
Fig 2.5 Triangular Crop
CHAPTER 3
COLOR SPACE
A color model is
an abstract mathematical model describing the way colors can
be represented as tuples of numbers, typically as three or four values or color components (e.g. RGB and CMYK are color models). However, a color model with no
associated mapping function to an absolute color space is a more or less arbitrary color system with no
connection to any globally-understood system of color interpretation.
Adding a certain mapping function
between the color model and a certain reference color space results in a
definite "footprint" within the reference color space. This
"footprint" is known as a gamut, and, in combination
with the color model, defines a new color
space. For example, Adobe RGB and sRGB are two different absolute color spaces, both based on the RGB
model.
In the most generic sense of the
definition above, color spaces can be defined without the use of a color model.
These spaces, such as Pantone, are in effect a given set of names or
numbers which are defined by the existence of a corresponding set of physical
color swatches. This article focuses on the mathematical model concept.
3.1 RGB
COLOR MODEL
The RGB color model is an additive color model in which red, green,
and blue light are added together in various ways to
reproduce a broad array of colors. The name of the
model comes from the initials of the three additive primary colors, red, green, and blue.
The main purpose of the RGB color model
is for the sensing, representation, and display of images in electronic
systems, such as televisions and computers, though it has also been used in
conventional photography.
Before the electronic age, the RGB color model already had a solid theory
behind it, based in human perception of colors.
RGB is a device-dependent color model: different devices detect or reproduce a
given RGB value differently, since the color elements (such as phosphors or
dyes) and their response to the individual R, G, and B levels vary from
manufacturer to manufacturer, or even in the same device over time. Thus an RGB
value does not define the same color across
devices without some kind of color management.
Typical
RGB input devices are color TV and video cameras, image scanners, and digital cameras. Typical RGB output devices are TV
sets of various technologies (CRT, LCD, plasma, etc.), computer and mobile phone displays, video
projectors, multicolor LED displays, and large screens such as JumboTron,
etc. Color printers, on the other hand, are not RGB devices, but subtractive color devices (typically CMYK color model). RGB
color model is as shown in fig. 3.1
Fig 3.1 RGB Color Model
3.2 YCbCr
YCbCr or Y′CbCr,
sometimes written YCBCR or Y′CBCR, is a family of color spaces used as a part of the color image
pipeline in
video and digital photography systems. Y′ is the luma component
and CB and
CR are the blue-difference and red-difference chroma components. Y′ (with prime) is distinguished from Y
which is luminance, meaning that light intensity is
non-linearly encoded using gamma correction.
Y′CbCr is not an absolute
color space, it is a way of encoding RGB information. The actual color displayed depends on
the actual RGB colorants used
to display the signal. Therefore a value expressed as Y′CbCr is predictable
only if standard RGB colorants or an ICC profile are used.\
YCbCr and Y′CbCr
are a practical approximation to color processing and perceptual uniformity,
where the primary colors corresponding roughly
to red, green and blue are processed into perceptually meaningful information.
By doing this, subsequent image/video processing, transmission and storage can
do operations and introduce errors in perceptually meaningful ways. Y′CbCr is
used to separate out a luma signal (Y′) that can be stored with high resolution
or transmitted at high bandwidth, and two chroma components (CB and CR) that
can be bandwidth-reduced, sub sampled, compressed, or otherwise treated
separately for improved system efficiency. Fig 3.2 shows the CbCr plane.
Fig.3.2
The CbCr plane
CHAPTER 4
SYSTEM REQUIREMENTS
In
this section we will see the components required to implement the above system
is
as follows:
1.
Webcam
2.
PC (Laptops)
3.
Speakers
4.1
Webcam:
Web
camera which we are using has following features:
Ø Lens
high Quality 3P lens
Ø Interface:
USB 2.0 High-Speed (UVC)
Ø Online
Snapshot Button
Ø Built
In Microphone
Ø 6
white LED indication lights for night view
Ø Manual
Control Button for LCDs
Ø Suitable
for both laptop and desktop
Ø Zoom
function with four choices for the zoom (1x, 2x, 3x & 4x)
Ø With
16 sorts of photo frame & mosiases image effect with driver
Ø Focus
Rate: with VGA (640x480) format rate up to 30fps
Ø Automatic
exposure control, Auto White balance
Ø Color:
RGB 24 (true color 24 bit)
4.2
Personal computer (PC):
The PC should have following features to
install the MATLAB software. Below table 4.1 shows the requirement to install
MATLAB.
Ø 32 bit windows
Operating System
|
Processor
|
Disk Space
|
Ram
|
Windows
XP
(Service
Pack 1 or 2)
Windows2000
(Service
Pack 3 or 4)
Windows
Server 2003
(Service
Pack 1 or 2)
Windows
Vista
|
Intel
Pentium (Pentium IV and
above)Intel Celeron Intel Xeon
Intel
Core
AMD
Athlon
AMD Opteron
|
510
MB (MATLAB only)
|
512
MB
(1024
recommended)
|
Table 4.1 Operating
System Specification
Ø Graphics
16-, 24-, or 32-bit OpenGL capable graphics adapter DirectX
9.0c (August 2005) or later
Ø Additional
requirements
·
Microsoft Word 2000, 2002, 2003, or 2007
is required to run
·
MATLAB Notebook, Microsoft Excel 2000,
2002, 2003, or 2007 is required to run
·
MATLAB® Builder for Excel® and Excel®
Link.
4.3
Speakers:
Computer speakers, or multimedia speakers, are speakers external to a computer
that disable the lower fidelity built-in speaker. They often have a low-power
internal amplifier. The standard audio connection is a 3.5 mm
(approximately 1/8 inch) stereo jack plug often color-coded lime
green (following the PC 99 standard) for computer sound cards. A plug and socket for a
two-wire (signal and ground) coaxial cable that is widely used to connect analog audio and video
components.
Features vary by manufacturer, but may include the
following:
Ø An LED power indicator.
Ø A
3.5 mm headphone jack.
Ø Controls
for volume, and sometimes bass and treble
Ø A
remote volume control.
CHAPTER
5
INTRODUCTION OF MATLAB
MATLAB (matrix laboratory) is a numerical computing environment and fourth-generation
programming language. Developed by Math Works, MATLAB allows matrix manipulations,
plotting of functions and data,
implementation of algorithms, creation of user interfaces, and interfacing with programs
written in other languages, including C, C++, Java,
and Fortran.
Although
MATLAB is intended primarily for numerical computing, an optional toolbox uses
the MuPAD engine,
allowing access to symbolic computing capabilities.
An additional package, Simulink, adds graphical multi-domain simulation
and Model-Based Design for dynamic and embedded systems.
5.1 Syntax:
The MATLAB application is built around the MATLAB
language. The simplest way to execute MATLAB code is to type it in the Command
Window, which is one of the elements of the MATLAB Desktop. When code is
entered in the Command Window, MATLAB can be used as an interactive
mathematical shell. Sequences of commands can be saved
in a text file, typically using the MATLAB Editor, as a script or encapsulated into a function,
extending the commands available.
5.2 MATLAB built in function:
To
load an image into MATLAB, we can use the "import data" GUI (the same
way as you would for a text file or similar), or you can use the "imread"
function. To use "imread", we must have the directory where the image
is located in your list of directories. Then use the syntax:
>> myimage = imread('myimage.extension');
Use
of a semicolon is recommended especially here since images contain large
amounts of data.
If the image is a color image, MATLAB
will (for most data formats that are compatible with it) convert the image data
to the RGB color space by default. The separate channels are represented by
the third dimension of
the image. The following code separates the channels of the image and indicates
the color of each channel.
5.3
Visualization of images:
To visualize an image or a section of an
image, use the imshow function:
>> imshow(myimage);
This will show a figure (often scaled down) of the image.
5.4 Data Acquisition Toolbox
Just get to the Matlab Start menu
Type “imaqhwinfo” to
see the below block
Fig 5.3:Matlab Function For Hardware Discription
Notice
that the adaptor is ‘Winvideo’ Any webcam you connect is accessed through this adaptor.
Now the main parts are as follows:
5.4.1 Connecting webcam to the computer through USB
vid = videoinput(‘winvideo’, 1, ‘RGB24_320x240′);
Specify the
adaptor name and resolution
5.4.2 Open Preview window to view
video at runtime
preview(vid);
preview(vid);
This will open a window similar to yahoo
messenger Webcam interface. And you will be able to view the video demo the
webcam at runtime
5.4.3 Capture
data = getsnapshot(vid);
data = getsnapshot(vid);
This command will store the image of
that instant into the variable data in a matrix of 320X240. That’s it now that
you have the image of what your robot is looking at or probably the desired
object, you may carry on processing and provide proper control signals to your
Parallel Ports.
5.5 Contrast Enhancement techniques
The Image Processing Toolbox™ contains several image enhancement
routines. Three functions are particularly suitable for contrast
enhancement: imadjust, histeq, and adapthisteq. This demo
compares their use for enhancing grayscale and truecolor images.
5.5.1 Contents
Step 1:
Load Images
Read in two grayscale
images: pout.tif and tire.tif. Also read in an indexed RGB
image: shadow.tif.
pout = imread('pout.tif');
tire = imread('tire.tif');
[X map] = imread('shadow.tif');
shadow = ind2rgb(X,map);
% convert to truecolor
Step 2:
Resize Images
To
make the image comparison easier, resize the images to have the same width.
Preserve their aspect ratios by scaling their heights.
width = 210;
images = {pout, tire,
shadow};
for k = 1:3
dim = size(images{k});
images{k} =
imresize(images{k},[width*dim(1)/dim(2) width],'bicu
bic');
end
pout = images{1};
tire = images{2};
shadow = images{3};
Using the default
settings, compare the effectiveness of the following three techniques:
Ø Imadjust:
It increases the
contrast of the image by mapping the values of the input intensity image to new
values such that, by default, 1% of the data is saturated at low and high
intensities of the input data.
Ø Histeq:
It performs histogram
equalization. It enhances the contrast of images by transforming the values in
an intensity image so that the histogram of the output image approximately
matches a specified histogram (uniform distribution by default).
Ø Adapthisteq:
It performs
contrast-limited adaptive histogram equalization. Unlike histeq, it
operates on small data regions (tiles) rather than the entire image. Each
tile's contrast is enhanced so that the histogram of each output region
approximately matches the specified histogram (uniform distribution by
default). The contrast enhancement can be limited in order to avoid amplifying
the noise which might be present in the image.
pout_imadjust = imadjust(pout);
pout_histeq =
histeq(pout);
pout_adapthisteq =
adapthisteq(pout);
imshow(pout);
title('Original');
figure,
imshow(pout_imadjust);
title('Imadjust');
Fig 5.4 Original image
Fig 5.5 Adjusted image
CHAPTER
6
IMPLEMENTATION
OF 6S-GRS
6.1 System Overview:
The basic representation of
the system is shown below as a figure 7.1.
Fig 6.1 Basic
Representation of 6s-GRS System.
The basic working of each
system can be explained as follows:
6.1.1 Hand Gestures:
A sign language is used as a form of communication by the dumb people. All
the gestures are performed on white background in front of image capturing device
(Web camera).
6.1.2 Web Camera:
The
device is code (MATLAB) driven operated with specified frames per trigger.
6.1.3
Manipulating Device:
Each gesture has its own unique feature, so the system manipulates on the
captured image and recognizes the gesture made by the dumb people.
6.1.4 Speakers:
If
the gesture made by the dumb people is recognized then the corresponding audio
file is triggered else a beep sound is produced in the speaker.
6.2
Flowchart
|
Digital camera working at a rate of
S frames/trigger
|
|
Obtain
Sth frame
|
|
Cropped
images
|
|
Recognize Active areas
|
|
Recognize the
position of gesture
|
|
Hand gestures
|
|
Initiate gesture equivalent Audio
file
|
|
Produce Beep sound
|
|
YES
|
|
NO
|
Fig 6.2 Flow Chart of 6s-GRS System.
Each block can be briefed
as follows:
Ø Hand Gestures:
A sign language is used as a form of communication
by the dumb people. All the gestures are performed on white background in front
of image capturing device (Web camera).
Ø
Web Camera:
The device is code (MATLAB) driven operated with specified frames per
trigger.
Ø Obtain Sth
Frame:
From this block it is a software part. Here the 20th frame is
obtained from the set of frames captured.
Ø Cropping Image:
Each gesture has its own unique feature, so a certain portion of image is
cropped using the cropping areas .Then the cropped images are stored.
Ø Recognize active
areas:
We are using a red
color band wearing on our fingers (active areas). When our gestures are
captured by the camera only the active areas will be highlighted. Thus, as a
result our job is done with ease since the code written by us locates the
active areas in the cropped images.
Ø Decision making (gesture
recognized):
Based on the position and the unique
feature of the gesture, a decision is made whether it is the valid gesture or
not. If it is a valid gesture, then trigger the corresponding audio file or
else trigger a beep sound indicating an error.
Ø
Speech Produced:
If the cropped pixel areas have values within the threshold then the
corresponding audio file is triggered else a beep sound is produced.
6.3 Code Structure
Before explaining the code
structure it is required to understand the basic concept involved in color
images like RGB, YUY etc.
6.3.1 Basic
concept of RGB image:
A digital image is two dimensional arrays
consisting of basic elements called as pels or pixels and its location in the
image. A typical color image requires two matrices: a colormap, and an image
matrix. The colormap is an ordered set of values that represent the colors in
the image. For each image pixel, the image matrix contains a corresponding
index into the colormap. (The elements of the image matrix are floating-point
integers, or flints, which MATLAB stores as double-precision values). The size
of the colormap matrix is n-by-3 for an image containing n colors. Each row of
the colormap matrix is a 1-by-3 red, green, blue (RGB) color vector.
color = [R G B]
That specifies the
intensity of the red, green, and blue components of that color. R, G, and B are
real scalars that range from 0.0 (black) to 1.0 (full intensity). MATLAB
translates these values into display intensities when you display an image and
its colormap. When MATLAB displays an indexed image, it uses the values in the
image matrix to look up the desired color in the colormap. For instance, if the
image matrix contains the value 18 in matrix location (86,198), then the color
for pixel (86,198) is the color from row 18 of the colormap.
6.3.2 Code structure of image acquisition device:
The steps involved are:
Step 1: Install Your Image Acquisition Device
Follow the setup instructions that come with your
image acquisition device. Setup typically
involves:
Ø Installing the frame grabber board in your computer.
Ø Installing any software drivers required by the
device. These are supplied by the device vendor.
Ø Connecting a camera to a connector on the frame
grabber board. Verifying that the camera is working properly by running the
application software that came with the camera and viewing a live video stream.
Step 2: Retrieve Hardware Information
In this step, you get
several pieces of information that the toolbox needs to uniquely identify the
image acquisition device you want to access. You use this information when you
create an image acquisition object. For ex;
imaqhwinfo
ans =
InstalledAdaptors: {'dcam' 'winvideo'}
MATLABVersion: '7.4 (R2007a)'
ToolboxName: 'Image Acquisition
Toolbox'
ToolboxVersion: '2.1 (R2007a)'
Step 3: Create a Video Input Object
In this step you create the video
input object that the toolbox uses to represent the connection between MATLAB
and an image acquisition device. Using the properties of a video input object,
you can control many aspects of the image acquisition process. For ex: vid =
videoinput('dcam',1,'Y8_1024x768').
Step 4: Preview the Video Stream
Before you begin, you might want to see a preview of
the video stream to make sure that the image is satisfactory. For example,
preview(vid).
Step 5: Acquire Image Data
After you create the video
input object and configure its properties, you can acquire data.
Step 6: Clean Up
When you finish using your image
acquisition objects, you can remove them from memory and clear the MATLAB
workspace of the variables associated with these objects.
delete(vid)
clear
close(gcf)
6.3.3 Code structure of
manipulating system
For any gesture there is an unique features .the
features may be 1,2 or many. To recognize easily these features we have wrapped
a color band across each finger as shown in figures. As it is explained above
that red objects in the image has the red component higher value and blue has
lower value, hence the task required to perform is to recognize these pixel
values.
Fig 6.3: Cropped Image Fig 6.4: RGB Values For the Cropped Image
Now a matrix
is initialized where each element in the matrix determines the presence of each
unique features .hence the advantage of this structure is that we are not
storing any images but the variables to specify the presence or absence of unique
feature (false or true). It should be understood that all the images captured
with plain background of any color other than red, blue and green.
6.3.4 Code structure to initiate
the voice file
Once
all the unique features of gestures are represented in the form of a matrix, these
matrix elements can be used to initiate the “gesture equivalent voice”. Before
that the gesture equivalent voices has to be recorded for each gesture and
audio files are stored in the memory. A simple switch statement can be used to
initiate for a particular values of matrix elements an audio file (.wav format)
can be triggered. To trigger an audio file its sampling rate and number of bits
per sample has to be known before hand.
CHAPTER 7
TESTING AND
RESULTS
We performed different
tests and their results are as follows:
7.1 On stored images
Images on few gestures are stored in the
memory. These gestures are used as standards to compare the gesture made by
dumb people. Real time images are taken and are simply compared by the
instruction (base_im1==real_im1) written in MATLAB.
Where base_im1 is stored image of the
gesture and real_im1 is real time gesture image. The result was “false” for
many times even though gesture done was the same. It is shown as below:
Fig 7.1: Image of base_im1 Fig7.2: Image of real_im1
7.2 Comparison Using Edge Detection
The web camera was initiated to capture
10 frames per trigger. Out of these 10 frames, any two successive frames are
taken and then they are converted into grayscale images and applied edge
detection to find edges of the gesture in those two frames. The two images are
then subtracted .The resulted image is not zero because foreground object
(Gesture) is not stationary whereas, the background is stationary object.
A
set threshold is maintained to see whether the number of white pixels in the
image lies within that threshold. If it is “true” then the gesture was
identified properly. However for the same gesture threshold was use to be
changing all the time because the number of bright pixels in that image is a
function of amount of illumination of light. It is shown as below:
|
Fig 7.3: Frames Obtained
From Web Camera
|
Fig 7.4: 30th
Frame
Fig 7.5: 50th Frame
Fig 7.6: Subtracted
Image Fig 7.7: Edge Detected Image
7.3 Finding Highest Red Component and
Lowest Blue Component in
RGB Image
For any RGB image the red, green and
blue component value of can be clearly observed using MATLAB tool. For a red
object in an image has highest red component and lowest blue or green component
value. This principle was applied for the gestures.
A red colored band was wrapped around
the fingers, for different gestures the red band was placed at different
locations in the image. It was easy to find the gesture by simply locating the
positions of red band in an image. Here the problem was that the other portion
of hand also has the highest red component and lowest blue or green component
value. It occurs most of the time because the amount of light falling on the
gesture area varies constantly. It can be observed as below:
Fig
7.8: Image Showing Red Pixel Value of Gesture
7.4 YCbCr IMAGES
The gesture RGB image was converted into
YCbCr gesture image using available MATLAB function “RGB2YCbCr”.Now from YCbCr
image the chrominance of red (Cr) components can be obtained and hence red band
on the fingers are highlighted i.e. it has gray value of 255.These act as
active areas to identify the gesture performed. It can be observed from below:
Fig 7.9: Ycbcr Gesture Image Fig 7.10: Image Showing Only Cr Components
7.5
Enhanced YCbCr Images
From
the YCbCr images the Cr components can be made more highlighted by image
processing such as contrast adjustment available in image processing toolbox.
Fig 7.11: Normal Cr Components Fig7.12: Enhanced Cr Components
CHAPTER 8
DESIGN OF GUI
USING MATLAB®
After
implanting any algorithm, it is very important to design an attractive GUI.
MATLAB® provides many tools to design GUI.
8.1 Starting
GUIDE
There are many ways to start GUIDE. You can start
GUIDE from the:
Ø Command line by typing guide
Ø Start menu by selecting MATLAB > GUIDE (GUI
Builder)
Ø
|
|
Ø MATLAB toolbar by clicking the GUIDE button
Ø However you start GUIDE, it displays the GUIDE Quick
Start dialog box shown in the Figure7.1.
Fig
8.1 Starting GUIDE
The
GUIDE Quick Start dialog box contains two tabs:
Ø Create New GUI: Asks you to start creating your new GUI by choosing
a template for it. You can also specify the name by which the GUI is saved.
Ø Open Existing
GUI: Enables you to open an
existing GUI in GUIDE. You can choose a GUI from your current directory or
browse other directories.
8.2 Designing
GUI
On clicking ‘Blank GUI (default)’ and
then ‘Ok’ the following window will occur. This consists of many options for
adding Push buttons, Text, Check box, Toggle box etc. By using all these tools
we can create GUI as for our requirement.
Fig 8.2 Designing GUI
8.3 Saving GUI
After creating GUI, saving is must. On saving any
GUI, GUIDE creates a template M-file and opens it in our default editor. This
template contains all the call back functions. These functions specify the
action to be performed, when the respective option is selected.
Fig 8.3 Saving GUI
Fig 8.4 Final GUI
CHAPTER 9
APPLICATIONS
This 6S-grs device can be use by dumb people to
communicate with the society. Since
dumb people have various gestures of their own to communicate, this is very
difficult to understand by a common man. Thus sixth sense device will help them
to communicate with us in an easier way. Moreover if a dumb person would like
to address to a huge crowd our sixth sense device would be of great use.
It can also be used as a
language mediator while visiting other countries. For example if a
person goes to country like Japan, there people prefer speaking in Japanese
than English. Thus by using our sixth sense device a person could communicate
easily.
CHAPTER 10
FUTURE
ENHANCEMENT
For
future enhancement the equipments we need are:
1)
DSP processor
2)
Digital Camera
3)
LCD display
4)
Speakers
A digital camera is placed
on a location somewhere above the abdomen region. In this camera’s memory store
the images of all the possible gestures (standard) used by the dumb people.
Then a DSP processor chip has to be interfaced with the camera which has a code
burnt into it. Then whatever gestures are done by the person who has put on a
camera will be captured and compared with the gesture’s images stored in the
camera memory in real time.
Once this process is done,
then immediately the text corresponding to that particular gesture will be
displayed and voice will be told from the speaker using a text to speech
converter module.
CHAPTER 11
CONCLUSION
The goal of this project is to create a gesture
recognition system and help the dumb people to communicate with the society.
Based on the unique pattern and position of each gesture the audio file
corresponding to that particular gesture is triggered.
Test
was first performed on stored gestures and then the test proceeded on real time
gestures. The result is comparatively much better because in this case most of
the memory is saved. This is because as this project all about just identifying
the position and the pattern of each gesture based on the active areas (red
color bands) so there is no need to store the gesture images in the database.
Thus the output of the project is more accurate i.e. the audio file
corresponding to each gesture in real time is played after the comparison is
done.
Thus
the result of this project is satisfactory most of the occasions. Moreover it
also works even when the light intensity is low. This project sixth sense
device would be more effective and accurate in giving the result.
REFERENCES
Literature references:
Ø Tim Morris (2004). “Computer Vision and Image Processing”. Palgrave
Macmillan.
Ø Wilhelm Burger and Mark J. Burge (2007). ”Digital Image Processing: An
Algorithmic Approach Using Java.”
Ø Bernd Jähne (2002). “Digital Image Processing”
Ø Rafeal
C.Gonzalez and Richard E. Woods(2001) “Digital Image Processing”
Websites:
Ø Color spaces
Ø Sixth sense- a wearable gestural interface
Ø Pranav
Mistry: The thrilling potential of Sixth Sense technology
The next chapter 15 deals with Testing and results.
CHAPTER 15
TESTING AND RESULTS
15.1 PROBLEMS FACED DURING IMPLEMENTATION
1. SOLDERING- Soldering of MEMS chip WM7120 is a
challenging task for us as the size of the chip is in micron level and normal
tip of soldering machine is large compared to size of our chip.
2. DTMF-
Detection of voice from mobile phone is a vital part of our project as if there
is less strength of voice than it is difficult for DTMF to detect.
3. POWER SUPPLY-
As per the requirement the minimum voltage required by circuit is 5 voltage but
the voltage provided by phone is 3 voltage thus we have to rectify the cause
for this.
4.PARISITIC EFFECT-As
the circuit is small automatic resistance path can be developed in continuous
current path due to the size of the components .
15.2
SOLUTION FOR OUR PROBLEMS
1. SOLDERING
PROBLEM-We reached to the conclusion by going for tip soldering that is
known as machine soldering through experts ,as we have been guided by our
lecturers and our experts about the problem that can arise due to imperfect
soldering .
2. DTMF PROBLEM-
We reached to the conclusion by setting the keypad tone in maximum strength in
phone setting so that DTMF can easily interprets the voice and decode it .
3. POWER SUPPLY
PROBLEM-We reached to the conclusion by placing preamplifier circuit
between mobile and DTMF which fulfilled the given requirements of the circuits
.
4. PARISITIC EFFECT PROBLEM-We reached to
the conclusion by checking each and every node connection of our general
purpose board through multimeter which shows the default in the circuit if
there is any discontinuity of the circuit.
The next chapter 16 deals with conclusion of our project.
CHAPTER 16
CONCLUSION
As we control our car using
hardware and software requirements and proved that we can control our car
through our mobile phone and keep a track on it through video calling which is
possible through 3G.Our idea gives a easiest way of monitoring and controlling
the systems through WIRELESS COMMUNICATION AND MEMS .We can implement this idea
not only in cars but any other devices in which human labor is involved .Being
in a part of this techno world we adhere our self to improvise our techniques
of using the smallest and cheapest way by using MEMS chip.
The next chapter 17 deals with Scope for improvement of
our project.
CHAPTER 17
SCOPE FOR IMPROVEMENT
Fig
17.1-This figure shows enhanced version of our project.
EXPLANATION:
Our project can be modified as per the requirements by
incorporating the following modules:
1.IVS- Inter
Vehicle source is used to detect the obstacle by itself so it reduces the
function of monitoring continuously from other vehicles.
2. GPS –Global
position system module helps us to track the position of our car if our defined
range in infinite as per our limit.
3. RADAR-It
helps us to protect our system from the neighboring obstacles.
CHAPTER 18
COST DETAILS
LIST OF COMPONENTS
1.Soldering machine
2.General purpose board
3.Step Down Transformer
4.MEMS Microphone
(WM7120)
5.Microcontroller
(AT89C52)
6.DTMF
(CM8870)
7.Relay (12V)
8.Relay(6V)
9.3G activated phone
10.Preamplifier circuit
11.Darlington on sink driver
Circuit (ULN2003AP)
12.LED
13.Capacitors
(220uf,.3uf,.1uf)
14. Voltage regulator IC
(7805)
15. Silicon diodes
(IN 4007)
16.Toy car
17.Rechargable battery
|
QUANTITY
1
1
1
2
2
2
4
4
1
1
1
10
6
2
4
1
2
|
COST
Rs 200
Rs 50
Rs 100
Rs 800
Rs 70
Rs 140
Rs 100
Rs 80
Rs 4000
Rs 110
Rs 20
Rs 60
Rs 100
Rs 40
Rs 20
Rs 250
Rs 70
|
REFRENCES
LITERATURE OF REFRENCES
1. ”The
8051 Microcontroller and embedded systems” by Muhammad Ali Mazidi and Janice
Gillispie Mazidi,6th edition, Pearson Education.
2. “The
8051 Microcontroller Architecture , Programming
and applications “ by Kenneth J Ayala,2nd edition ,Pernam
International Publishing.
WEBSITES
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