1. BRIEF HISTORY OF OMEGA
Mr. Y. P. Agarwal, an eminent & qualified Electronic
professional, foundedOMEGA ELECTRONICS in the year 1962. Heading
the company as Chief Executive.He is continuing his expert guidance
and OMEGA is achieving new horizons ofsuccess under his
supervision. Attributing to his foresight, OMEGA iscurrently one of
the organizations in the country, which enjoys an all
Indiapatronage and coverage. An ISO certified Company 9001:2000,
situated inMalviya Nagar RICO Industrial Area, Jaipur,
(Rajasthan).
Product Range: ANTENNA Trainers,GPS Trainer,Radar Trainer,RFID
Trainer,Instrumentation Trainers, Communication Trainers,
Electricity Trainer, LAN Trainer,VLSI Trainers, Microprocessor,
Microcontroller & Interfaces Trainers,Consumer Electronics
Demonstration Trainers,Test and Measuring Instruments,Microwave
Test Benches,Educational Wall Charts,Robotics Kits,Decade Boxes
(R,L,C),Analog Electronics Lab,Digital Electronics Lab,Power
Electronics Lab,Breadboards, Power Project Board, Circuit Lab
Trainers,Physics Systems Training,Fibre Optics Trainers,Power
Supplies.
Omega Teaching Aids & Equipments bring technical theory to
life, teachingthe latest technology and helping trainees to develop
valuable troubleshooting skills.
Industrial tour at Omega Electronics:
There are 6 sections available with manufacturing unit Jaipur
.These are1.R & D Section:In this section basically the circuit
development board,and designing of new trainer kit board has been
done by respective R &D Engineers.They are trying to design the
new application based trainer set-up.
2.Painting Section:In this section basically circuit layouts are
developed which are approved by R&D section engineers .The
layout of the circuit have been made on printed ckt. Board.
3.Mechanical Section:In this section they use to make basically
transformers, and designing of their winding and inductors,sensors
relays etc. All the hardware related work have been done in this
section.The packaging of trainer kits is also done by this section
engineers.
4.Wiring Section:In this section after layouts of ckts have been
designed by painting section they are delivered to this section and
here soldering of all ckt. Component on that printed ckt. Board. By
section engineers.All the internal connections of the trainer board
has been done in this section and also testing of trainer board are
done here. Then they are again send to mchanical section for
packaging and then exported to marketing unit.
5.Quality and Testing Section:In this section all type of
testing on trainer board has been done both internal as well as
external by quality engineers and if they measure perfect reading
or desired output from that trainer board then they give their
permission to exporting that kit.
6.Store and Finishing good centre:In this section, after passing
all the trainer circuits board with quality-test sections are
stored.They are the trainer board which are completely ready to
send marketing division or for delivering.
Basic ElectronicsDiodes In simple terms, a diode is a device
that restricts the direction of flow of charge carriers.
Essentially, it allows an electric current to flow in one
direction, but blocks it in the opposite direction. There are a
variety of diodes; A few important ones are described below.
Switching diodesSwitching diodes, sometimes also called small
signal diodes, are single diodes in a discrete package. A switching
diode provides essentially the same function as a switch.
Zener diodesDiodes that can be made to conduct backwards. This
effect, called Zener breakdown, occurs at a precisely defined
voltage, allowing the diode to be used as a precision voltage
reference.
Schottky diodesSchottky diodes are constructed from a metal to
semiconductor contact. They have a lower forward voltage drop than
a standard diode.
Varicap or varactor diodesThese are used as voltage-controlled
capacitors. These are important in PLL (phase-locked loop) and FLL
(frequency-locked loop) circuits, allowing tuning circuits, such as
those in television receivers, to lock quickly, replacing older
designs that took a long time to warm up and lock.
Light-emitting diodes (LEDs)In a diode formed from a direct
band-gap semiconductor, such as gallium arsenide, carriers that
cross the junction emit photons when they recombine with the
majority carrier on the other side. Depending on the material,
wavelengths (or colors) from the infrared to the near ultraviolet
may be produced. The forward potential of these diodes depends on
the wavelength of the emitted photons: 1.2 V corresponds to red,
2.4 to violet.
Transistors A transistor is a three-terminal semiconductor
device that can perform two functions that are fundamental to the
design of electronic circuits: amplification and switching. Put
simply, amplification consists of magnifying a signal by
transferring energy to it from an external source, whereas a
transistor switch is a device for controlling a relatively large
current between or voltage across two terminals by means of a small
control current or voltage applied at a third terminal.There are
two main types of transistors: Field-Effect Transistorsand Bipolar
Junction Transistors. A BJT is formed by joining three sections of
semiconductor material, each with adifferent doping concentration.
The three sections can be either a thin n regionsandwiched between
p+ and p layers, or a p region between n and n+ layers, where the
superscript plus indicates more heavily doped material. The
resulting BJTs are called pnpand npn transistors.Electron flow is
dominant while pnp transistors rely mostly on the flow of
holes".
FIELD EFFECT TRANSISTORThe field-effect transistor (FET) is a
transistor that relies on an electricfield to control the shape and
hence the conductivity of a channel of onetype of charge carrier in
semiconductor material. FETs are sometimescalled unipolar
transistors to contrast their single-carrier-type operationwith the
dual-carrier-type operation of bipolar (junction) transistors(BJT).
The concept of the FET predates the BJT, though it was not
physicallyimplemented until after BJTs due to the limitations of
semiconductormaterials and the relative ease of manufacturing BJTs
compared to FETs atthe time.
3. SOLDERINGSoldering is a process in which two or more metal
items are joined togetherby melting and flowing a filler metal into
the joint, the filler metalhaving a lower melting point than the
work piece. Soldering differs fromwelding in that the work pieces
are not melted. There are three forms ofsoldering, each requiring
higher temperatures and each producing anincreasingly stronger
joint strength: soft soldering, which originally useda tin-lead
alloy as the filler metal, silver soldering, which uses an
alloycontaining silver, and brazing which uses a brass alloy for
the filler. Thealloy of the filler metal foreach type of soldering
can be adjusted tomodify the melting temperature of the filler.
Soldering appears to be a hotglue process, but it differs from
gluing significantly in that the fillermetals alloy with the work
piece at the junction to form a gas- andliquid-tight bond.
Fig.4 (a):-good joint (b):-bad joint
Soft soldering is characterized by having a melting point of the
fillermetal below approximately 400 C (752 F), whereas silver
soldering andbrazing use higher temperatures, typically requiring a
flame or carbon arctorch to achieve the melting of the filler. Soft
solder filler metals aretypically alloys (often containing lead)
that have liquids temperaturesbelow 350C.In the soldering process,
heat is applied to the parts to bejoined, causing the solder to
melt and to bond to the work pieces in analloying process called
wetting. In stranded wire, the solder is drawn upinto the wire by
capillary action in a process called wicking. Capillaryaction also
takes place when the work pieces are very close together
ortouching. The joint strength is dependent on the filler metal
used, wheresoft solder is the weakest and the brass alloy used for
brazing is thestrongest. Soldering, which uses metal to join metal
in a molecular bond haselectrical conductivity and is water- and
gas-tight. Applications of soldering:-Soldering was historically
used to make jewelry items, cooking ware andtools. Currently, the
two most common uses of soldering are in plumbing andin electronics
where it is used to connect electrical wiring and to
connectelectronic components to printed circuit boards (PCBs).
Types of soldering:-1. Soft soldering.2. Silver soldering3. Brazing
soldering
Required Items for soldering:- Soldering iron Filler metal
Flux
Solders:-Soldering filler materials are available in many
different alloys fordiffering applications. In electronics
assembly, the eutectic alloy of 63%tin and 37% lead (or 60/40,
which is almost identical in performance to theeutectic) has been
the alloy of choice. Other alloys are used for plumbing,mechanical
assembly, and other applications.Common solder alloys are mixtures
of tin and lead, respectively: 63/37: melts at 183 C (361 F)
(eutectic: the only mixture that melts ata point, instead of over a
range) 60/40: melts between 183190 C (361374 F) 50/50: melts
between 185215 C (365419 F)
Flux:-The purpose of flux is to facilitate the soldering
process. The obstacle toa successful solder joint is an impurity at
the site of the union, e.g.dirt, oils or oxidation. The impurities
can be removed by mechanicalcleaning or by chemical means, but the
elevated temperatures required tomelt the filler metal (the solder)
encourages the work piece (and thesolder) to re-oxidize. This
effect is accelerated as the solderingtemperatures increase and can
completely prevent the solder from joining tothe work piece. One of
the earliest forms of flux was charcoal, which actsas a reducing
agent and helps prevent oxidation during the solderingprocess. Some
fluxes go beyond the simple prevention of oxidation and alsoprovide
some form of chemical cleaning (corrosion)."Hard soldering" or
"silver soldering" (performed with high-temperaturesolder
containing up to 40% silver) is also often considered a form of
brazing, since it involves filler materials with melting points in
thevicinity of, or in excess of, 450 C. Although the term "silver
soldering"is used much more often than "silver brazing", it may be
technicallyincorrect depending on the exact melting point of the
filler in use. Insilver soldering ("hard soldering"), the goal is
generally to give abeautiful, structurally sound joint, especially
in the field of jewellery.Induction soldering is a process which is
similar to brazing. The source ofheat in induction soldering is
induction heating by high-frequency ACcurrent in a surrounding
copper coil. This induces currents in the partbeing soldered, heat
then being generated by resistive heating. The copperrings can be
made to fit the part needed to be soldered for precision in thework
piece. Induction soldering is a process in which a filler
metal(solder) is placed between the facing surfaces of (to be
joined) metals. Thefiller metal in this process is melted at a
fairly low temperature. Fluxesare commonly used in induction
soldering. This is a process which isparticularly suitable for
soldering continuously. The process is usuallydone with coils that
wrap around a cylinder/pipe that needs to be soldered.Some metals
are easier to solder than others. Copper, silver, and gold areeasy.
Iron, mild steel and nickel are found to be more difficult. Because
oftheir thin, strong oxide films, stainless steel andaluminium are
even more difficult. Titanium, magnesium, cast iron, some
high-carbon steels,ceramics, and graphite can be soldered but it
involves a process similar tojoining carbides.
4. SWITCHES:In electronics, a switch is an electrical component
that can break anelectrical circuit, interrupting the current or
diverting it from oneconductor to another.The most familiar form of
switch is a manually operated electromechanicaldevice with one or
more sets of electrical contacts. The mechanismactuating the
transition between these two states (open or closed) can beeither a
"toggle" (flip switch for continuous "on" or "off") or
"momentary"(push-for "on" or push-for "off") type.In electronics
engineering, an ideal switch describes a switch that: has no
current limit during its ON state has infinite resistance during
its OFF state has no voltage limit during its OFF state has zero
rise time and fall time during state changes switches only once
without "bouncing" betweenon and off positionsA switch that is
operated by another electrical circuit iscalled a relay. Large
switches may be remotely operated by a motor drivemechanism. Some
switches are used to isolate electric power from a system,providing
a visible point of isolation that can be pad-locked if necessaryto
prevent accidental operation of a machine during maintenance, or
toprevent electric shock.Types of switches:1. SPST (Single Pole
Single Through)2. SPDT (Single Pole Double Through)3. DPST (Double
Pole Single Through)4. DPDT (Double Pole Double Through)Standard
SwitchesA simple on-off switch: This type can be used to switch the
power supply toa circuit.When used with mains electricity this type
of switch must be in the livewire, but it is better to use a DPST
switch to isolate both live andneutral.
Push-to-make:A push-to-make switch returns to its normally open
(off) position when yourelease the button, this is shown by the
brackets around ON. This is thestandard doorbell switch.
Push-to-break :A push-to-break switch returns to its normally
closed (on) position when yourelease the button.
Single Pole, Double Throw = SPDT:This switch can be on in both
positions, switching on a separate device ineach case. It is often
called a changeover switch. For example, a SPDTswitch can be used
to switch on a red lamp in one position and a green lampin the
other position.A SPDT toggle switch may be used as a simple on-off
switch by connecting toCOM and one of the A or B terminals.
ON-OFF-ONSPDT Centre Off:A special version of the standard SPDT
switch. It has a third switchingposition in the centre which is
off. Momentary (ON)-OFF-(ON) version are also available where the
switch returns to the central off position whenreleased.1) SPDT
toggle switch2) SPDT slide switch3) SPDT rocker switchDouble Pole,
Single Throw = DPST:A pair of on-off switches which operate
together .A DPST switch is often used to switch mains electricity
because it canisolate both the live and neutral
connections.Example-DPST rocker switchDouble Pole, Double Throw =
DPDT:A pair of on-on switches which operate together. As shown in
omega demonstration board.
INTRODUCTION TO ROBOTICS AND AUTOMOTIONRobotics is the branch of
technology that deals with the design, construction, operation, and
application of robots, as well as computer systems for their
control, sensory feedback, and information processing. These
technologies deal with automated machines that can take the place
of humans in dangerous environments or manufacturing processes, or
resemble humans in appearance, behavior, and/or cognition.The
concept of creating machines that can operate autonomously dates
back to classical times, but research into the functionality and
potential uses of robots did not grow substantially until the 20th
century.Throughout history, robotics has been often seen to mimic
human behavior, and often manage tasks in a similar fashion. Today,
robotics is a rapidly growing field, as technological advances
continue, research, design, and building new robots serve various
practical purposes, whether domestically, commercially, or
militarily. ETYMOLOGYThe word robotics was derived from the word
robot, which was introduced to the public by Czech. The word robot
comes from the Slavic word robota, which means labor. The play
begins in a factory that makes artificial people called robots,
creatures who can be mistaken for humans similar to the modern
ideas of androids.AUTUNOMOUS ROBOTAutonomous robots are robots that
can perform desired tasks in unstructured environments without
continuous human guidance. Many kinds of robots have some degree of
autonomy. Different robots can be autonomous in different ways. A
high degree of autonomy is particularly desirable in fields such as
spaceexploration cleaning floors, mowing lawns, and waste water
treatment.Some modern factory robots are "autonomous" within the
strict confines of their direct environment. It may not be that
every degree of freedom exists in their surrounding environment,
but the factory robot's workplace is challenging and can often
contain chaotic, unpredicted variables. The exact orientation and
position of the next object of work and (in the more advanced
factories) even the type of object and the required task must be
determined. This can vary unpredictable (at least from the robot's
point of view).A fully autonomous robot has the ability to: Gain
information about the environment (Rule #1) Work for an extended
period without human intervention (Rule #2) Move either all or part
of itself throughout its operating environment without human
assistance (Rule #3) Avoid situations that are harmful to people,
property, or itself unless those are part of its design
specifications (Rule #4)An autonomous robot may also learn or gain
new capabilities like adjusting strategies for accomplishing its
task(s) or adapting to changing surroundings.Autonomous robots
still require regular maintenance, as do other machines.Autonomous
robotMOBILE ROBOTA mobile robot is an automatic machine that is
capable of movement in any given environment.
Spying mobile robot
A spying robot is an example of a mobile robot capable of
movement in a given environment.BASIC PARTS OF ROBOTICSConstruction
materialRegarding the material used in the actual frame of the
robot, several options are available, such as e.g. aluminium,
steel, various forms of plastic etc. The frame of a robot should,
of course, preferably be constructed using a material that is both
sturdy and light and, for that reason, aluminium is often chosen.
Steel is typically too heavy to be practical in a small robot,
whereas many forms of plastic easily break. The frame of the robot
used in this course (the Boe-bot) is made in aluminium. SensorsThe
purpose of robotic sensors is to measure either some physical
characteristic of the robot (for example, its acceleration) or some
aspect of its environment (for example, the detected intensity of a
light source). The raw data thus obtained must then, in most cases,
be processed further before being used in the brain of the robot.
For example, an infrared (IR) proximity sensor may provide a
voltage (depending on the distance to the detected object) as its
reading, which can then be converted to a distance, using the
characteristics of the sensor available from its data sheet.Sensors
allow robots to receive information about a certain measurement of
the environment, or internal components. This is essential for
robots to perform their tasks, and act upon any changes in the
environment to calculate the appropriate response. They are used
for various forms of measurements, to give the robots warnings
about safety or malfunctions, and to provide real time information
of the task it is performing.TouchCurrent robotic and prosthetic
hands receive far less tactile information than the human hand.
Recent research has developed a tactile sensor array that mimics
the mechanical properties and touch receptors of human fingertips.
The sensor array is constructed as a rigid core surrounded by
conductive fluid contained by an elastomeric skin. Electrodes are
mounted on the surface of the rigid core and are connected to an
impedance-measuring device within the core. When the artificial
skin touches an object the fluid path around the electrodes is
deformed, producing impedance changes that map the forces received
from the object. The researchers expect that an important function
of such artificial fingertips will be adjusting robotic grip on
held objects.VisionComputer vision is the science and technology of
machines that see. As a scientific discipline, computer vision is
concerned with the theory behind artificial systems that extract
information from images. The image data can take many forms, such
as video sequences and views from cameras.Computer vision systems
rely on image sensors which detect electromagnetic radiation which
is typically in the form of either visible light or infra-red
light. Infrared proximity sensors
An infrared proximity sensor (or IR sensor, for short), consists
of an emitter and a detector. The emitter, a light-emitting diode
(LED), sends out infrared light, which bounces off nearby objects,
and the reflected light is then measured by the detector (e.g. a
phototransistor). Some IR sensors can also be used for measuring
the ambient light level, i.e. the light observed by the detector
when the emitter is switched off.
Other sensorsOther common forms of sensing in robotics use
LIDAR, RADARSONAR, SOUND and LIGHT.
ActuatorsAn actuator is a device that allows a robot to take
action, i.e. to move or manipulate the surroundings in some
otherway. Motors, of course, are very common types of actuators.
Other kinds of actuation include, for example, the use of
microphones (for human-robot interaction).Movements can be
generated in various ways, using e.g. electrical motors,pneumatic
or hydraulic systems etc. In this course, we shall only consider
electrical, direct-curren(DC) motors and, in particular, servo
motors. Thus,when referring to actuation in this course, the use of
such motors is implied.Note that actuation normally requires the
use of motor controller in connection with the actual motor. This
is so, since the microcontroller (see below) responsible for
sending commands to the motor cannot, in general, provide
sufficient current to drive the motor.
Actuators are like the "muscles" of a robot, the parts which
convert stored energy into movement. By far the most popular
actuators are electric motors that spin a wheel or gear, and linear
actuators that control industrial robots in factories. But there
are some recent advances in alternative types of actuators, powered
by electricity, chemicals, or compressed air.
Electric motorsThe vast majority of robots use electric motors,
often brushed and brushless DC motors in portable robots or AC
motors in industrial robots and CNC machines. These motors are
often preferred in systems with lighter loads, and where the
predominant form of motion is rotational.
Linear actuatorsVarious types of linear actuators move in and
out instead of by spinning, and often have quicker direction
changes, particularly when very large forces are needed such as
with industrial robotics. They are typically powered by compressed
air (pneumatic actuator) or an oil (hydraulic actuator).Series
elastic actuatorsA spring can be designed as part of the motor
actuator, to allow improved force control. It has been used in
various robots, particularly walking humanoid robots.Power sourceAt
present mostly (lead-acid) batteries are used as a power source.
Many different types of batteries can be used as a power source for
robots. They range from lead acid batteries which are safe and have
relatively long shelf lives but are rather heavy to silver cadmium
batteries that are much smaller in volume and are currently much
more expensive. Designing a battery powered robot needs to take
into account factors such as safety, cycle lifetime and weight.
Generators, often some type of internal combustion engine, can also
be used. However, such designs are often mechanically complex and
need fuel, require heat dissipation and are relatively
heavy.ROBOTIC LOCOMOTIONDifferential driveA differential wheeled
robot is a mobile robot whose movement is based on two separately
driven wheels placed on either side of the robot body. It can thus
change its direction by varying the relative rate of rotation of
its wheels and hence does not require an additional steering
motion.To balance the robot, additional wheels or casters may be
added.
Path of wheels through a turn. The wheels are not connected,
despite how it appears.If both the wheels are driven in the same
direction and speed, the robot will go in a straight line. If both
wheels are turned with equal speed in opposite directions, as is
clear from the diagram shown, the robot will rotate about the
central point of the axis. Otherwise, depending on the speed of
rotation and its direction, the center of rotation may fall
anywhere on the line defined by the two contact points of the
tires. While the robot is traveling in a straight line, the center
of rotation is an infinite distance from the robot. Since the
direction of the robot is dependent on the rate and direction of
rotation of the two driven wheels, these quantities should be
sensed and controlled precisely.A differentially steered robot is
similar to the differential gears used in automobiles in that both
the wheels can have different rates of rotations, but unlike the
differential gearing system,a differentially steered system will
have both the wheels powered. Differential wheeled robots are used
extensively in robotics, since their motion is easy to program and
can be well controlled. Virtually all consumer robots on the market
today use differential steering primarily for its low cost and
simplicity.Car drive (Ackerman)The intention of Ackermann geometry
is to avoid the need for tires to slip sideways when following the
path around a curve. The geometrical solution to this is for all
wheels to have their axles arranged as radii of a circle with a
common center point. As the rear wheels are fixed, this center
point must be on a line extended from the rear axle. Intersecting
the axes of the front wheels on this line as well requires that the
inside front wheel is turned, when steering, through a greater
angle than the outside wheel.
Rather than the preceding "turntable" steering, where both front
wheels turned around a common pivot, each wheel gained its own
pivot, close to its own hub. While more complex, this arrangement
enhances controllability by avoiding large inputs from road surface
variations being applied to the end of a long lever arm, as well as
greatly reducing the fore-and-aft travel of the steered
wheels.Synchro driveThe synchro drive system is a two motor,
three/four wheeled drive configuration where one motor rotates all
wheels to produce motion and the other motor turns all wheels to
change direction: The left figure shows the wheels in the 0 degree
position--in this position the robot will move up. The right figure
shows the wheels turned -45 degrees. Note that all wheels have
turned an equal amount. Using separate motors for translation and
wheel rotation guarantees straight-line translation when the
rotation motor is not actuated. This mechanical guarantee of
straight-line motion is a big advantage over the differential drive
method where two motors must be dynamically controlled to produce
straight-line motion. Arbitrary motion paths can of course be done
by actuating both motors simultaneously. Wheel alignment is
critical in this drive system--if all wheels are not parallel, the
robot will not translate in a straight line.Skid-steter
driveSkid-steer locomotion is commonly used on tracked vehicles
such as tanks and bulldozers, but is also used on some four- and
six-wheeled vehicles. On these vehicles, the wheels (or tracks) on
each side can be driven at various speeds in forward and reverse
(all wheels on a side are driven at the same rate). There is no
explicit steering mechanism--as the name implies steering is
accomplished by actuating each side at a different rate or in a
different direction, causing the wheels or tracks to slip, or skid,
on the ground.In the above left figure, the wheels on the left side
are driven forward and the wheels on the right side are driven in
reverse at the same rate. The result is a clockwise zero
radius.turn about the center of the vehicle shown in the right
figureArticulated driveArticulated drive is similar to the car-type
drive except the turning mechanism is a deformation in the chassis
of the vehicle, not pivoting of wheels:
This design has the same disadvantages of the car-type drive: if
multiple wheels are driven and a differential is not used, wheel
slippage will occur. This design is commonly used in construction
equipment where wheel slippage is not an issue (speeds are slow and
the coefficient of friction with the ground is low).Pivot
drivePivot drive is a unique type of locomotion used by one of the
Robo-Rat groups during the previous course (pivot drive is my name
for the system). The pivot drive system is composed of a two parts:
1) a four-wheeled chassis with non-pivoting wheels and, 2) a
rotating platform which can be raised or lowered:
The wheels are the platform are driven by the same motor,
although the platform is geared to rotate slowly. When the platform
is raised, the wheels will translate the robot in a straight
line--the platform will spin but as it is not touching the ground
it has no effect. When a turn is required, the robot stops the
drive motor and activates the motor which lowers the platform. Once
the platform is in the down position, the drive motor is activated.
Now the drive motor spins the robot since the wheels are off the
ground. When the robot has rotated to the desired heading, the
drive motor is stopped and the platform is raised. Now the robot
can translate again using the drive motor.Dual differential drive
The ideal wheeled drive for a Robo-Rats robot mechanically
guarantees straight-line motion. This is important because it
simplifies odometry sensing and eliminates time-critical processing
on the Handyboard. The synchro drive does give a mechanical
guarantee of straight-line motion (assuming the wheels are properly
aligned) but it would be difficult to build using Lego parts.The
dual differential drive, given its name because it utilizes two
mechanical differentials, also guarantees straight-line motion and
it is relatively simple to construct in Lego. Unlike the use of the
differential in a car-type drive, where it distributes input force
to two output shafts, the dual differential drive, or DDD, uses its
differentials to combine the forces from two input shafts and uses
the resulting sum to drive a wheel (each drive wheel has its own
differential).
HANDY BOARDThe Handy Board is the "brains" of your Robo-Rat. It
is a hand-held, battery-powered microcontroller board that controls
all the sensors and motors of your robot. The microcontroller can
be programmed using an assembler or compiler, or with Interactive
C--an interpreted version of the C language. For this course we
will be using Interactive C because it provides an convenient
environment to explore/control your robot.VisionThe visual sensing
system can be based on anything from the traditional camera, sonar,
and laser to the new technology radio frequency identification
(RFID), which transmits radio signals to a tag on an object that
emits back an identification code. Visual sensors help robots to
identify the surrounding and take appropriate action.[3] Robots
analyze the image of the immediate environment imported from the
visual sensor. The result is compared to the ideal intermediate or
end image, so that appropriate movement can be determined to reach
the intermediate or final goal.TouchTouch sensory signals can be
generated by the robot's own movements. It is important to identify
only the external tactile signals for accurate operations. Previous
solutions employed the Wiener filter, which relies on the prior
knowledge of signal statistics that are assumed to be stationary.
Recent solution applies an adaptive filterto the robots logic. It
enables the robot to predict the resulting sensor signals of its
internal motions, screening these false signals out. The new method
improves contact detection and reduces false
interpretation.UsageTouch patterns enable robots to interpret human
emotions in interactive applications. Four measurable
featuresforce, contact time, repetition, and contact area changecan
effectively categorize touch patterns through the temporal decision
tree classifier to account for the time delay and associate them to
human emotions with up to 83% accuracy. The Consistency Index is
applied at the end to evaluate the level of confidence of the
system to prevent inconsistent reactions.Robots use touch signals
to map the profile of a surface in hostile environment such as a
water pipe. Currently, with the integration of touch sensors, the
robots first acquire a random data point; the algorithm of the
robot will then determine the ideal position of the next
measurement according to a set of predefined geometric primitives.
This improves the efficiency by 42%.Hearing (Signal
processing)Accurate audio sensor requires low internal noise
contribution. Traditionally, audio sensors combine acoustical
arrays and microphones to reduce internal noise level. Recent
solutions combine also piezoelectric devices. These passive devices
use the piezoelectric effect to transform force to voltage, so that
the vibration that is causing the internal noise could be
eliminated. On average, internal noise up to about 7dB can be
reduced. Robots may interpret strayed noise as speech instructions.
Current voice activity detection (VAD) system uses the complex
spectrum circle centroid (CSCC) method and a maximum
signal-to-noise ratio (SNR) beamformer. Because humans usually look
at their partners when conducting conversations, the VAD system
with two microphones enable the robot to locate the instructional
speech by comparing the signal strengths of the two microphones.
UsageRobots can perceive our emotion through the way we talk.
Acoustic and linguistic features are generally used to characterize
emotions. The combination of seven acoustic features and four
linguistic features improves the recognition performance when
compared to using only one set of features. MovementAutomated
robots require a guidance system to determine the ideal path to
perform its task. However, in the molecular scale, nano-robots lack
such guidance system because individual molecules cannot store
complex motions and programs. Therefore, the only way to achieve
motion in such environment is to replace sensors with chemical
reactions. Currently, a molecular spider that has one streptavidin
molecule as an inert body and three catalytic legs is able to
start, follow, turn and stop when came across different DNA
origami. The DNA-based nano-robots can move over 100nm with a speed
of 3nm/min. In a TSI operation, which is an effective way to
identify tumors and potentially cancer by measuring the distributed
pressure at the sensors contacting surface, excessive force may
inflict a damage and have the chance of destroying the tissue. The
application of robotic control to determine the ideal path of
operation can reduce the maximum forces by 35% and gain a 50%
increase in accuracy compared to human doctors.PerformanceEfficient
robotic exploration saves time and resources. The efficiency is
measured by optimality and competitiveness. Optimal boundary
exploration is possible only when a robot has square sensing area,
starts at the boundary, and uses the Manhattan metric. In
complicated geometries and settings, a square sensing area is more
efficient and can achieve better competitiveness regardless of the
metric and of the starting point.Robot Control Techniques:Open Loop
Control (Nonservo Control)No Feedback! Basic control suitable for
systems with simple loads, Tight speed control is not required, no
position or rate-of-change sensors, on each axis, there is a fixed
mechanical stop to set the endpoint of the robot, its called
stop-to-stop or pick-and-place systems.The desired change in a
parameter is calculated (joint angles), the actuator energy needed
to achieve that change is determined, and the amount of energy is
applied to the actuator. If the model is correct and there are no
disturbances, the desired change is achieved.
Feedback Control LoopDetermine rotor position and/or speed from
one or more sensors. Position of robot arm is monitored by a
position sensor, power to the actuator is altered so that the
movement of the arm conforms to the desired path in terms of
direction and/or velocity. Errors in positioning are
corrected.Feedforward ControlIt is a control, where a model is used
to predict how much action to take, or the amount of energy to use.
It is used to predict actuator settings for processes where
feedback signals are delayed and in processes where the dynamic
effects of disturbances must be reduced.Adaptive ControlThis
control uses feedback to update the model of the process based upon
the results of previous actions. The measurements of the results of
previous actions are used to adapt the process model to correct for
changes in the process and errors in the model. This type of
adaption corrects for errors in the model due to long-term
variations in the environment but it cannot correct for dynamic
changes caused by local disturbances.11. Power supply
OMEGA DEMONSTRATION OF DIFFERENT TRANSFORMER A power supply is a
device that supplies electrical energy to one or more electric
loads. The term is most commonly applied to devices that convert
one form of electrical energy to another, though it may also refer
to devices that convert another form of energy (e.g., mechanical,
chemical, solar) to electrical energy. A regulated power supply is
one that controls the output voltage or current to a specific
value; the controlled value is held nearly constant despite
variations in either load current or the voltage supplied by the
power supply's energy source. Every power supply must obtain the
energy it supplies to its load, as well as any energy it consumes
while performing that task, from an energy source.Depending on its
design, a power supply may obtain energy from: Electrical energy
transmission systems. Common examples of this includepower supplies
that convert AC line voltage to DC voltage. Energy storage devices
such as batteries and fuel cells. Electromechanical systems such as
generators and alternators. Solar power.A power supply may be
implemented as a discrete, stand-alone device or as an integral
device that is hardwired to its load. In the latter case,
forexample, low voltage DC power supplies are commonly integrated
with their loads in devices such as computers and household
electronics.
Commonly specified power supply attributes include: The amount
of voltage and current it can supply to its load. How stable its
output voltage or current is under varying line and load
conditions. How long it can supply energy without refueling or
recharging (applies to power supplies that employ portable energy
sources)
Power supplies types:Power supplies for electronic devices can
be broadly divided into line-frequency (or "conventional") and
switching power supplies. The line-frequency supply is usually a
relatively simple design, but it becomes increasingly bulky and
heavy for high-current equipment due to the need for large
mains-frequency transformers and heat-sinked electronic regulation
circuitry.Conventional line-frequency power supplies are sometimes
called "linear," but that is a misnomer because the conversion from
AC voltage to DC is inherently non-linear when the rectifiers feed
into capacitive reservoirs. Linear voltage regulators produce
regulated output voltage by means of an active voltage divider that
consumes energy, thus making efficiency low. A switched-mode supply
of the same rating as a line-frequency supply will be smaller, is
usually more efficient, but will be more complex.DC power
supply:
An AC powered unregulated power supply usually uses a
transformer to convert the voltage from the wall outlet (mains) to
a different, nowadays usually lower, voltage. If it is used to
produce DC, a rectifier is used toconvert alternating voltage to a
pulsating direct voltage, followed by a filter, comprising one or
more capacitors, resistors, and sometimes inductors, to filter out
(smooth) most of the pulsation. A small remaining unwanted
alternating voltage component at mains or twice mains power
frequency (depending upon whether half- or full-wave rectification
is used)rippleis unavoidably superimposed on the direct output
voltage.For purposes such as charging batteries the ripple is not a
problem, and the simplest unregulated mains-powered DC power supply
circuit consists of a transformer driving a single diode in series
with a resistor.
Before the introduction of solid-state electronics, equipment
used valves (vacuum tubes) which required high voltages; power
supplies used step-up transformers, rectifiers, and filters to
generate one or more direct voltages of some hundreds of volts, and
a low alternating voltage for filaments. Only the most advanced
equipment used expensive and bulky regulated power supplies.
12. PHYSICAL INTERFACING DEVICES
An electrical connector is an electro-mechanical device for
joining electrical circuits as an interface using a mechanical
assembly. The connection may be temporary, as for portable
equipment, require a tool for assembly and removal, or serve as a
permanent electrical joint between two wires or devices. There are
hundreds of types of electrical connectors. Connectors may join two
lengths of flexible copper wire or cable, or connect a wire or
cable or optical interface to an electrical terminal. In computing,
an electrical connector can also be known as a physicalinterface
(compare Physical Layer in OSI model of networking). Cable
glands,known as cable connectors in the U.S., connect wires to
devices mechanically rather than electrically and are distinct from
quick-disconnectsperforming the latter.
Properties of electrical connectors:An ideal electrical
connector would have a low contact resistance and high insulation
value. It would be resistant to vibration, water or other
contaminants, and pressure. It would be easily mated/unmated,
unambiguously preserve the orientation of connected circuits,
reliable, carry one or multiple circuits. Desirable properties for
a connector also include easy identification, compact size, rugged
construction, durability (capable of many connect/disconnect
cycles), rapid assembly, simple tooling, and low cost. No single
connector has all the ideal properties. The proliferation of types
is a reflection of the differing importance placed on the design
factors.Some of the interfacing devices are:1. USB Connector
(Universal Serial Bus)2. CAT5 (Category 5)3. VGA Connector (Video
Graphics Array)4. BNC Connector (Bayonet NeillConcelman)5. HDMI
(High Definition Multimedia Interface)6. DVI (Digital Visual
Interface)
USB Connector (Universal Serial Bus):USB (Universal Serial Bus)
is an industry standard developed in themid-1990s that defines the
cables, connectors and protocols used forconnection, communication
and power supply between computers and electronic devices.USB was
designed to standardise the connection of computer peripherals,
such as keyboards, pointing devices, digital cameras, printers,
portable media players, disk drives and network adapters to
personal computers, both to communicate and to supply electric
power. It has become commonplace on other devices, such as
smartphones, PDAs and video game consoles. USB has effectively
replaced a variety of earlier interfaces, such as serial and
parallel ports, as well as separate power chargers for portable
devices.CAT 5 (CATEGORY 5):Category 5 cables (Cat 5) is a twisted
pair cable for carrying signals. This type of cable is used in
structured cabling for computer networks such as Ethernet. It is
also used to carry other signals such as telephony and video. The
cable is commonly connected using punch down blocks and modular
connectors. Most Category 5 cables are unshielded, relying on the
twisted pair design and differential signaling for noise
rejection.
Fig 24: Category 5 patch cable in T568B wiring
VGA Connector (Video Graphics Array):A Video Graphics Array
(VGA) connector is a three-row 15-pin DE-15connector. The 15-pin
VGA connector is found on many video cards, computer monitors, and
some high definition television sets. On laptop computers or other
small devices, a mini-VGA port is sometimes used in place of the
full-sized VGA connector.
Fig 25: A VGA Cable
BNC Connector (Bayonet NeillConcelman):The BNC connector
(Bayonet NeillConcelman) is a common type of RF connector used for
coaxial cable. It is used with radio, television, and
otherradio-frequency electronic equipment, test intstruments, video
signals, andwas once a popular computer network connector. BNC
connectors are made to match the characteristic impedance of cable
at either 50 ohms or 75 ohms. It is usually applied for frequencies
below 3 GHz and voltages below 500 Volts.
Fig 26: Male 50 ohm BNC connector
HDMI (High Definition Multimedia Interface):High-Definition
Multimedia Interface (HDMI) is a compact audio/video interface for
transmitting uncompressed digital data. It is a digital alternative
to consumer analog standards, such as radio frequency (RF) coaxial
cable, composite video, S-Video, SCART, component video,
D-Terminal,or VGA. HDMI connects digital audio/video sources (such
as set-top boxes, DVD players, HD DVD players, Blu-ray Disc
players, AVCHD camcorders, personal computers (PCs), video game
consoles such as the PlayStation 3 and Xbox 360, and AV receivers)
to compatible digital audio devices, computer monitors, video
projectors, tablet computers, and digital televisions.
Practical Work in OMEGA :EXPERIMENT FIRSTINTRODUCTION:Traffic
signals are used to control the flow of vehicles.Inthe recent
years, the need of transportation has gain immenseimportance for
logistics as well as for common human. This hasgiven rise to the
number of vehicles on the road. Due to thisreason, traffic jams and
road accidents are a common sight inany busy city. Traffic Signals
provide an easy, cheap, automaticand justified solution to the road
points where the vehicles mayturn to other directions e.g.
roundabouts, culverts, busy walkthroughs etc. BASIC IDEA The
project we have chosen is an 8-lanetraffic controller. The basic
idea behind the design is to avoidthe collision of vehicles by
providing appropriate signals todifferent directions for a limited
time slot, after which the nextwaiting drivers will be given same
treatment. In This way acycle will be established which will
control the traffic. CONTROL SIGNALS The control signals are
3-lights.Top light is Red(Stop), Middle light is Yellow(Wait)Bottom
light is Green(Go). STATES OF TRAFFIC FLOWThere are 8-lanes and at
most two ways can be safely open.
WORKING PRINCIPLEIC2, which is heart of the circuit, is adecade
counter. In this counter for every pulse fed to pin-14,potential
keeps shifting from D1 to D9 in cyclic order. IC1 isused as a pulse
generator and generates pulses in regularconfigurable intervals.
These intervals can be changed byvarying VR1. The circuit is
designed in such a way that out ofnine pulses, relay RL1 remains
triggered for 4 pulses, relay RL2for 1 pulse and relay RL3 for
remaining 4 pulses. Since D1-D4provide current to T1, T1 is on
whenever there is potential onany diode D1 to D4, which keeps relay
RL1 triggered. Similarlyother diodes are responsible for RL2 and
RL3 triggering. Red,Yellow and Green lamps can be connected to the
relays RL1,RL2 and RL3 respectively to complete your mini traffic
lightcontroller.
PCB DESIGN OF ELECTRONIC STOPWATCH
On day four and five we perform and analysis the circuit of
electronic stop watch and understand the design of this
circuit.Electronics has its impact on almost every field today. The
'Digital Stop Watch ' described here finds application in sports
and different fun games where even a fraction of second matters a
lot. Through this project we can count even the 1/10th of a second.
The counter immediately stops counting once the Stop switch is
pressed and when the Reset switch is pressed we again have 000
display in the 7-segment display.The project mainly employs two
Timer IC555 (IC1 & IC2), three Decade counter IC4033 (IC3, IC4
& IC5) and 7-segment displays in common cathode
configuration.
About the Circuit: In the circuit diagram, IC1 is used in
bistable mode and IC2 is used in astable mode. When the START
switch is pushed on, IC1 is triggered, its output at pin3 goes high
which in turn is applied to reset pin4 of IC2. Hence IC2 is
operating in the astable mode and it will generate pulses of
frequency 10Hz. The frequency is determined by the RC time constant
of the circuit. The output at pin3 of IC2 is applied to CLOCKIN
(pin1) terminal of first 4033 IC i.e. IC3. This IC being a decade
counter starts counting from 0 to 9. The corresponding 7-segment
display thus shows 0.1 seconds of measurement. After counting from
0 to 9 this IC will generate pulse at CLOCKOUT (pin5) terminal,
which is connected to the CLOCKIN terminal of second IC4033 (IC4).
Thus IC4 starts counting from 0 to 9. The corresponding 7-segment
display connected to IC4 display each second. The third 4033 IC
(IC5) also receives pulse at CLOCKIN terminal in similar manner and
counting starts. As long as the STOP switch is not pressed the
Stopwatch keeps on counting. The watch can count maximum up to 99.9
seconds. The circuit being a decade-up counter, after counting 99.9
seconds all three displays shows 000 and the process of counting
repeats.If the STOP switch is pressed at any instant between the
counting,output of IC1 goes low and correspondingly the RESET pin
of IC2 receives a negative going pulse and output goes low. So all
three counters stops counting.The reset pins of all the three 4033
IC's are connected together, so when RESET switch is pressed all
three counters gets reset.Here LED D1 connected at output pin3 of
IC2 indicates that the output pulses/clock pulses are generated and
circuit is operating properly.This is a mini digital stopwatch can
be used in sports or different fun games where even a fraction of
second matters a lot. The circuit counts minimum 0.1seconds and
maximum 99.9 seconds when START switch is pressed. You can stop
counting by pressing STOP switch. RESET switch is used to reset the
counting. The display is shown on three 7-segment displays.The
circuit uses total five ICs and three 7-segment display.
PCB Design of electronic stopwatch
Circuit diagram of electronic stopwatch
Project on Robotics:
Name of robot :Turning frog
Circuit Diagram:
Working:This circuit has four major parts: Sound sensor Wave
shaping circuit Oscillatory circuit Locomotion circuitSound
sensor:We used a microphone as sound sensor , it converts sound
signals in to electrical signals which will have a magnitude of
around 100 mv are less than that and might have frequency of 1000
2000 kHz. These signals are feed to the wave stabilizing part using
capacitor to block dc part.
Wave shaping circuit :In this part we have a first stage as
IC1/A and R3 is used as negative feedback ,due to the negative
feedback the noise tends to reduce due to the stabilizing effect of
the negative feedbackThe second stage is also negative feedback
stage with IC1/B and R5&C2 are parallel , this gives not gate
and integrator circuit as feed so if there are any sharp variation
in the inputs this provides a short circuit path for that and
provide a smooth wave at the output.Capacitor C3 is used to block
dc as wave is passed to the two inverters there may be a shift in
dc .Then we used a half wave rectifier stage to remove the negative
part of the wave then we pass the wave through the combination of
two inverters having VR as the feedback. So the two inverters has
360 phase shift it will form positive feedback.So the wave at the
input makes the low to high oscillations in the outputs.by varying
the VR resistance we can vary frequency of oscillation.
Locomotion stage :This oscillating input is feed to the iC2
/4017 at the clock inverse pin as clock pin (14) is given to the
vcc the ic makes a transition we negative edge pulse.IC2/4017 is a
decade counter it has outputs from O0 to O9 each output is raised
high at the negative pulse starting from O0 to 09 one after the
other .Pin 1-O5 and pin 2 O3 and pin 7 is O5.Pin 5 that is O6 is
shorted with pin 15 with is reset .so the reset will happen after
every 6 clock Pulse.When there is a high at pin-1 Q1&Q2 are on
and ML motor rotates and other motor doesnt rotate so bot will take
a turn.When there is a high at pin-2 Q1&Q2 are on & Q3 and
Q4 are also on, both the ML& MR motor rotates and so RObot will
go straight.When there is a high at pin-7 Q1&Q2 are off& Q3
and Q4 are also on, the ML motor rotates and so bot will go and
make turn.Rest other states bot doesnt move.
Industrial Work With Omega :Wiring Section:I also worked in
wiring section with omega engineers on trainer kits like
ETB-48,ETB-96,ETB-48,ETB-201,ES-215,ETB-52.Some of are given as
below:1.OEGA TYPE ETB-201:ETB-201 experimental training board has
been designed specially for the study & Verification of network
theorems in DC Circuits. The board here which we design in the lab
is absolutely self contained.The trainer board has mainly 7
sections like:1.DPM(20mAmp) :It is known as Digital Pulse Meter
,used for measuring current& voltage in Ac as well as Dc
both.but in our trainer board it is used as DC ammeter
(0-20mAmp).
2.DPM(0-20V):It is used for measuring voltage (DC) up to 20
V.this is only one in this trainer board.3.Resistances:Resistance
are used to prove following theorems like Thevenins ,Superposition
and Reciprocity .4.IC Regulated power supply:It is the dc power
supply and variable in nature range can be 0-12V & 9V at 20 mA
with a preset or potentiometer 4K7.5.On/off SwitchIt is a simple
on/off switch which is directly connected with transformer (step
down).
2.OMEGA TYPE ES-215:Experimental set up has been designed
specifically to study series & parallel resonance in an LCR
circuit (air core inductors,Two decade Condensers &resistance)
and damping effect by C and varying frequencies.
THEORY:for resonance condition in a circuit XL=XCthen
f=>F0(resonant frequency ) F0 = 1/(2LC)
Introduction:Radio communication involves the transmission &
reception of signals of selectable frequency. Such selection is
possible because every combination of L&C responds better to
voltages of one frequency than to voltages of other frequencies.The
signal frequency at which the circuit responds best is called the
resonant frequency of the circuit.There are 2 types of resonant
circuit :1.Series resonant circuit (R-L-C in series)2.Parallel
resonant(Tank Circuit),L-R-C in parallel.
3.OMEGA TYPE ETB-48:Experimental training board has been
designed specifically for the study of the characteristics of
vacuum DIODE.
Design panel description:The ON-OFF Switch, mains fuse and Main
ON indicator are located at the left hand lower side DPM regulator
0-20V/0-100V full scale dual range voltmeter, selected by a switch
& 0-20/200m Amp full scale mili-ammeter is fitted at the top of
panel.At the lower middle part of the panel,9-pin value base is
provided. At theleft side of valve base,variable H.T. voltage
(0-300V at 100mAmp) is provided.
Application:1.By use of this trainer kit ETB-48 are can be use
of diode as RECTIFIER. 2.Study of characteristic curves of
Thermionic vacuum Diode b/w Plate Current(Ib) and Plate
Voltage(eb).
WORKING AND PRINCIPLE OF KIT:Soon after the filament or heater
is supplied with heating power ,high thermionic emission takes
place from the cathode and if a small positive voltage is applied
to the plate with respect to the cathode ,these electrons are
attracted by the plate, thus constituting an electric current.In
the external circuit the electrons flow from plate to cathode. The
conventional current however flow in the reverse direction i.e.
from plate to cathode inside the electron tube and from cathode to
plate in the external circuit is Ib.
13. CONCLUSION
Spending my four weeks of training in OMEGA ELECTRONICS,
Jaipur,I conclude that it is very excellent industry of its own
type. They have achieved milestone in the field of, manufacturing
trainer board kits and Antenna kits.They conduct a PLC(programme
learning course) for summer training in their organization which is
a basic and fundamental course for learning industrial automation
and manufacturing. They also include Robotics course in the
curriculum with both aspects Electronics and Mechanically.They also
provide a good Lab practical environment with their Engineers.
I had earned a heap of knowledge about internal architecture of
lab trainer kits like ETB48,96 etc. from their specialist. Beyond
this they also taught and familiar us with new technology like
Interfacing devices, Sensors, Drives and gears which is useful to
build knowledge about Robotics. This industrial training will
definitely fill the gap between theoretical and practical
working.
14. REFRENCE
1.http://www.omegaelectronics.net/profile.asp2.http://electronics.howstuffworks.com/robot.htm3.http://engineering-ed.org/Robotics/documents.4.http://html.alldatasheet.com/html5.http://en.wikipedia.org/
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