ROBOTICERA

ROBOTIC-ERA INDEX

2008-11-13T09:45:00.009+05:30

Roboticera provides you the wide information over the circumference of the unbounded circle of technology

Some of the topics are as follows.... Select your topic of interest and get what you want..
Your valuable views and suggestions are welcomed...
Follow the blog for some more updated posts..

Enjoy !!!!!!!

VISIT MY PHOTOGRAPHY ADVENTURES AND PORTFOLIO ON " www.machinevision.co.nr "

ROBOTICS

MICROPROCESSORS-1

MICROPROCESSORS-2

MICROPROCESSORS-3

MICROPROCESSORS-4

NIGHT VISION

SENSORS

DRIVING TIPS

PARALLEL PORT ROBOTICS

ROBOT SENSORS

MOTORS

TATA NANO

GEARS

GEAR BOXES

NANO TECHNOLOGY

METAL DETECTORS

LIGHT SENSORS

VLF TECHNOLOGY

CAPACITORS

RADAR

TALON-MILITARY ROBOT

SOLID PROPELLENT ROCKETS

BIKE MAINTENANCE

TATA NANO

2008-08-30T20:17:00.005+05:30

The invention of the century.. The TATA NANO !!!

This car created a history in the automobile secotr in India. It has changed the outlook for the middle class families.. what makes it so special. ?? lets have a look

Why Nano?
The name 'Nano' was chosen as it denotes high technology and small size.
Most eagerly waited car
People world over were keen to see what Tata Motors' People's Car looked like, and know more about it. The Tata Motors website saw nearly 7.9 million hits on January 10 (the day the Nano was unveiled), while the Tata Nano website saw 4 million hits in 30 hours, making these sites among the busiest in the world.

The Nano website (www.tatanano.com) was developed within a short timeframe of 1.5 months and with limited resources.The entire portal has been built on open source technologies, involving minimum investment, following the essence of the Nano - low cost, but high technology.

Stylish, comfortable

Designed with a family in mind, the Nano has a roomy passenger compartment with generous leg space and head room.
Can comfortably seat four persons. Four doors with high seating position make ingress and egress easy.
With a length of 3.1 metres, width of 1.5 metres and height of 1.6 metres, with adequate ground clearance, it can effortlessly manoeuvre on busy roads in cities as well as in rural areas.
Its mono-volume design, with wheels at the corners and the powertrain at the rear, enables it to uniquely combine both space and manoeuvrability, which will set a new benchmark among small cars.

Fuel-efficient engine

The Nano has a rear-wheel drive, all-aluminium, two-cylinder, 623 cc, 33 PS, multi point fuel injection petrol engine. This is the first time that a two-cylinder gasoline engine is being used in a car with single balancer shaft.
The lean design strategy has helped minimise weight, which helps maximise performance per unit of energy consumed and delivers high fuel efficiency.
Performance is controlled by a specially designed electronic engine management system.

Meets all safety requirements

The Nano's safety performance exceeds current regulatory requirements. With an all sheet-metal body, it has a strong passenger compartment, with safety features such as crumple zones, intrusion
Resistant doors, seat belts, strong seats and anchorages, and the rear tailgate glass bonded to the body.
Tubeless tyres further enhance safety.

Environment-friendly

The Nano's tailpipe emission performance exceeds regulatory requirements. In terms of overall pollutants, it has a lower pollution level than two-wheelers being manufactured in India today.

The high fuel efficiency also ensures that the car has low carbon dioxide emissions, thereby providing the twin benefits of an affordable transportation solution with a low carbon footprint.

NANO TECHNOLOGY

2007-11-26T11:23:00.000+05:30

Hello Friends,
We have seen a couple of workings of very commom gadgets in previous posts..so I decided to take a new lane towards technology…
This post is on Nano technology…well, a very promising field at present..so read on to know more

· In 1965, engineer Gordon Moore predicted that the number of transistors on an integrated circuit -- a precursor to the microprocessor -- would double approximately every two years. Today, we call this prediction Moore's Law, though it's not really a scientific law at all.
· To fit more transistors on a chip, engineers have to design smaller transistors. The first chip had about 2,200 transistors on it. Today, hundreds of millions of transistors can fit on a single microprocessor chip. Even so, companies are determined to create increasingly tiny transistors, cramming more into smaller chips. There are already computer chips that have nanoscale transistors (the nanoscale is between 1 and 100 nanometers -- a nanometer is one billionth of a meter). Future transistors will have to be even smaller.
· A nanowire structure has an amazing length to width ratio..Nano wires can be very very thin…It is possible to create a nanowire with a diameter of just one nanaometer.
Human hair is usually between 60 and 120 micrometers wide. Let's assume you have found an exceptionally fine hair with a width of 60 micrometers. A micrometer is 1,000 nanometers, so you would have to cut that hair at least 60,000 times lengthwise to make a strand one nanometer thick.

PROPERTIES OF NANOWIRES:
· Depending on what it's made from, a nanowire can have the properties of an insulator, a semiconductor or a metal.semiconduxtors fall between Metals and Insulators,carrying the charge in right conditions.
· By arranging semiconductor wires in the proper configuration, engineers can create transistors, which either acts as a switch or an amplifier.
· Another interesting property is that some nanowires are ballistic conductors. In ballistic conductors, the electrons can travel through the conductor without collisions. Nanowires could conduct electricity efficiently without the byproduct of intense heat.
· At the nanoscale, elements can display very different properties than what we've come to expect. For example, in bulk, gold has a melting point of more than 1,000 degrees Celsius. By reducing bulk gold to the size of nanoparticles, you decrease its melting point, because when you reduce any particle to the nanoscale, there's a significant increase in the surface-to-volume ratio. Also, at the nanoscale, gold behaves like a semiconductor, but in bulk form it's a conductor. intersting isn’t it?? J
· Another similar example is …In bulk, aluminum isn't magnetic, but very small clusters of aluminum atoms are magnetic.
· Some elements, like silicon, don't change much at the nanoscale level. This makes them ideal for transistors and other applications. Others are still mysterious, and may display properties that we can't predict right now.

HOW NANOWIRES ARE MADE???

· Chemical vapor deposition (CVD) is an example of a bottom-up approach. In general, CVD refers to a group of processes where solids form out of a gaseous phase. Scientists deposit catalysts (such as gold nanoparticles) on a base, called a substrate.
· The catalysts act as an attraction site for nanowire formation. Scientists put the substrate in a chamber with a gas containing the appropriate element, such as silicon, and the atoms in the gas do all the work.
· First, atoms in the gas attach to atoms in the catalysts, then additional gas atoms attach to those atoms, and so on, creating a chain or wire. In other words, the nanowires assemble themselves.
· A new way to build nanowires is to print them directly to the appropriate substrate. A team of researchers in Zurich. First, carved a silicon wafer so that the raised portions on the wafer coincided with the way they wanted the nanowires arranged.
· They used the wafer like a stamp, pressing it against a synthetic rubber called PDMS. They then drew a liquid filled with gold nanoparticles, called a colloidal suspension, across the PDMS.
· The gold particles settled into the channels created by the silicon wafer stamp. Now the PDMS became a mold capable of transferring a "print" of gold nanowires onto another surface. PDMS molds can be used repeatedly and may play a role in the mass production of nanowire circuitry in the future

APPLICATIONS OF NANOWIRE:

· ELECTRONICS: Some nanowires are very good conductors or semiconductors, and their miniscule size means that manufacturers could fit millions more transistors on a single microprocessor. As a result, computer speed would increase dramatically.
· QUANTUM COMPUTERS: A team of researchers in the Netherlands created nanowires out of indium arsenide and attached them to aluminum electrodes. At temperatures near absolute zero, aluminum becomes a supercomputer, meaning it can conduct electricity without any resistance. The nanowires also became superconductors due to the proximity effect. The researchers could control the superconductivity of the nanowires by running various voltages through the substrate under the wires
· NANO ROBOTS: . Doctors could use the nanorobots to treat diseases like cancer. Some nanorobot designs have onboard power systems, which would require structures like nanowires to generate and conduct power.
· GENERATE ELECTRICITY: Using piezoelectric material, nanoscientists could create nanowires that generate electricity from kinetic energy. The piezoelectric effect is a phenomenon certain materials exhibit -- when you apply physical force to a piezoelectric material, it emits an electric charge. If you apply an electric charge to this same material, it vibrates. Piezoelectric nanowires might provide power to nano-size systems in the future, though at present there are no practical applications.

WORKING OF RADAR

2007-10-05T20:33:00.001+05:30

RADAR:

Radar is something that is in use all around us, although it is normally invisible. Air traffic control uses radar to track planes both on the ground and in the air, and also to guide planes in for smooth landings. Police use radar to detect the speed of passing motorists. NASA uses radar to map the Earth and other planets, to track satellites and space debris and to help with things like docking and maneuvering. The military uses it to detect the enemy and to guide weapons.

Meteorologists use radar to track storms, hurricanes and tornadoes. You even see a form of radar at many grocery stores when the doors open automatically! Obviously, radar is an extremely useful technology.

When people use radar, they are usually trying to accomplish one of three things:

Detect the presence of an object at a distance - Usually the "something" is moving, like an airplane, but radar can also be used to detect stationary objects buried underground. In some cases, radar can identify an object as well; for example, it can identify the type of aircraft it has detected.

Detect the speed of an object - This is the reason why police use radar.
Map something - The space shuttle and orbiting satellites use something called Synthetic Aperture Radar to create detailed topographic maps of the surface of planets and moons.

All three of these activities can be accomplished using two things you may be familiar with from everyday life: echo and Doppler shift. These two concepts are easy to understand in the realm of sound because your ears hear echo and Doppler shift every day. Radar makes use of the same techniques using radio waves.
In this article, we'll uncover radar's secrets. Let's look at the sound version first, since you are already familiar with this concept.

Echo and Doppler Shift :

When you shout into a well, the sound of your shout travels down the well and is reflected (echoes) off the surface of the water at the bottom of the well. If you measure the time it takes for the echo to return and if you know the speed of sound, you can calculate the depth of the well fairly accurately.Echo is something you experience all the time. If you shout into a well or a canyon, the echo comes back a moment later. The echo occurs because some of the sound waves in your shout reflect off of a surface (either the water at the bottom of the well or the canyon wall on the far side) and travel back to your ears. The length of time between the moment you shout and the moment that you hear the echo is determined by the distance between you and the surface that creates the echo.

Doppler shift is also common. You probably experience it daily (often without realizing it). Doppler shift occurs when sound is generated by, or reflected off of, a moving object. Doppler shift in the extreme creates sonic booms (see below). Here's how to understand Doppler shift (you may also want to try this experiment in an empty parking lot). Let's say there is a car coming toward you at 60 miles per hour (mph) and its horn is blaring. You will hear the horn playing one "note" as the car approaches, but when the car passes you the sound of the horn will suddenly shift to a lower note. It's the same horn making the same sound the whole time. The change you hear is caused by Doppler shift.

Here's what happens. The speed of sound through the air in the parking lot is fixed. For simplicity of calculation, let's say it's 600 mph (the exact speed is determined by the air's pressure, temperature and humidity). Imagine that the car is standing still, it is exactly 1 mile away from you and it toots its horn for exactly one minute. The sound waves from the horn will propagate from the car toward you at a rate of 600 mph. What you will hear is a six-second delay (while the sound travels 1 mile at 600 mph) followed by exactly one minute's worth of sound.

Doppler shift: The person behind the car hears a lower tone than the driver because the car is moving away. The person in front of the car hears a higher tone than the driver because the car is approaching.

Now let's say that the car is moving toward you at 60 mph. It starts from a mile away and toots it's horn for exactly one minute. You will still hear the six-second delay. However, the sound will only play for 54 seconds. That's because the car will be right next to you after one minute, and the sound at the end of the minute gets to you instantaneously.

The car (from the driver's perspective) is still blaring its horn for one minute. Because the car is moving, however, the minute's worth of sound gets packed into 54 seconds from your perspective. The same number of sound waves are packed into a smaller amount of time. Therefore, their frequency is increased, and the horn's tone sounds higher to you. As the car passes you and moves away, the process is reversed and the sound expands to fill more time. Therefore, the tone is lower.

You can combine echo and doppler shift in the following way. Say you send out a loud sound toward a car moving toward you. Some of the sound waves will bounce off the car (an echo). Because the car is moving toward you, however, the sound waves will be compressed. Therefore, the sound of the echo will have a higher pitch than the original sound you sent. If you measure the pitch of the echo, you can determine how fast the car is going.

FUNCTIONING OF RADAR:

We have seen that the echo of a sound can be used to determine how far away something is, and we have also seen that we can use the Doppler shift of the echo to determine how fast something is going. It is therefore possible to create a "sound radar," and that is exactly what sonar is. Submarines and boats use sonar all the time. You could use the same principles with sound in the air, but sound in the air has a couple of problems:
Sound doesn't travel very far -- maybe a mile at the most.
Almost everyone can hear sounds, so a "sound radar" would definitely disturb the neighbors (you can eliminate most of this problem by using ultrasound instead of audible sound).
Because the echo of the sound would be very faint, it is likely that it would be hard to detect. Radar therefore uses radio waves instead of sound. Radio waves travel far, are invisible to humans and are easy to detect even when they are faint.
Let's take a typical radar set designed to detect airplanes in flight. The radar set turns on its transmitter and shoots out a short, high-intensity burst of high-frequency radio waves. The burst might last a microsecond. The radar set then turns off its transmitter, turns on its receiver and listens for an echo.
The radar set measures the time it takes for the echo to arrive, as well as the Doppler shift of the echo. Radio waves travel at the speed of light, roughly 1,000 feet per microsecond; so if the radar set has a good high-speed clock, it can measure the distance of the airplane very accurately.
Using special signal processing equipment, the radar set can also measure the Doppler shift very accurately and determine the speed of the airplane.

Guys, so that was the Radar...Be in touch for more interesting topics

Reference of this topis .. - howstuffworks.com

NIGHT VISION

2007-09-06T18:10:00.000+05:30

The first thing you probably think of when you see the words night vision is a spy or action movie you've seen, in which someone straps on a pair of night-vision goggles to find someone else in a dark building on a moonless night. And you may have wondered "Do those things really work? Can you actually see in the dark?"

The answer is most definitely yes. With the proper night-vision equipment, you can see a person standing over 200 yards (183 m) away on a moonless, cloudy night! Night vision can work in two very different ways, depending on the technology used.

Image enhancement - This works by collecting the tiny amounts of light, including the lower portion of the infrared light spectrum, that are present but may be imperceptible to our eyes, and amplifying it to the point that we can easily observe the image.

Thermal imaging - This technology operates by capturing the upper portion of the infrared light spectrum, which is emitted as heat by objects instead of simply reflected as light. Hotter objects, such as warm bodies, emit more of this light than cooler objects like trees or buildings.
In this article, you will learn about the two major night-vision technologies. We'll also discuss the various types of night-vision equipment and applications. But first, let's talk about infrared light.

INFRARED LIGHT

In order to understand night vision, it is important to understand something about light. The amount of energy in a light wave is related to its wavelength: Shorter wavelengths have higher energy. Of visible light, violet has the most energy, and red has the least. Just next to the visible light spectrum is the infrared spectrum.

Infrared light is a small part of the light spectrum.

Infrared light can be split into three categories:

Near-infrared (near-IR) - Closest to visible light, near-IR has wavelengths that range from 0.7 to 1.3 microns, or 700 billionths to 1,300 billionths of a meter.

Mid-infrared (mid-IR) - Mid-IR has wavelengths ranging from 1.3 to 3 microns. Both near-IR and mid-IR are used by a variety of electronic devices, including remote controls.

Thermal-infrared (thermal-IR) - Occupying the largest part of the infrared spectrum, thermal-IR has wavelengths ranging from 3 microns to over 30 microns.

The key difference between thermal-IR and the other two is that thermal-IR is emitted by an object instead of reflected off it. Infrared light is emitted by an object because of what is happening at the atomic level.

THERMAL IMAGING

Here's how thermal imaging works:

1. A special lens focuses the infrared light emitted by all of the objects in view.

2. The focused light is scanned by a phased array of infrared-detector elements. The detector elements create a very detailed temperature pattern called a thermogram. It only takes about one-thirtieth of a second for the detector array to obtain the temperature information to make the thermogram. This information is obtained from several thousand points in the field of view of the detector array.

3. The thermogram created by the detector elements is translated into electric impulses.

4. The impulses are sent to a signal-processing unit, a circuit board with a dedicated chip that translates the information from the elements into data for the display.

5. The signal-processing unit sends the information to the display, where it appears as various colors depending on the intensity of the infrared emission. The combination of all the impulses from all of the elements creates the image.

Types of Thermal Imaging Devices :

Most thermal-imaging devices scan at a rate of 30 times per second. They can sense temperatures ranging from -4 degrees Fahrenheit (-20 degrees Celsius) to 3,600 F (2,000 C), and can normally detect changes in temperature of about 0.4 F (0.2 C).

There are two common types of thermal-imaging devices:

Un-cooled - This is the most common type of thermal-imaging device. The infrared-detector elements are contained in a unit that operates at room temperature. This type of system is completely quiet, activates immediately and has the battery built right in.

Cryogenically cooled - More expensive and more susceptible to damage from rugged use, these systems have the elements sealed inside a container that cools them to below 32 F (zero C). The advantage of such a system is the incredible resolution and sensitivity that result from cooling the elements. Cryogenically-cooled systems can "see" a difference as small as 0.2 F (0.1 C) from more than 1,000 ft (300 m) away, which is enough to tell if a person is holding a gun at that distance!

While thermal imaging is great for detecting people or working in near-absolute darkness, most night-vision equipment uses image-enhancement technology.

Working of MOTORS

2007-08-19T10:24:00.000+05:30

Let's start by looking at the overall plan of a simple two-pole DC electric motor. A simple motor has six parts, as shown in the diagram below:
· Armature or rotor
· Commutator
· Brushes
· Axle
· Field magnet
· DC power supply of some sort

An electric motor is all about magnets and magnetism: A motor uses magnets to create motion.

If you have ever played with magnets you know about the fundamental law of all magnets: Opposites attract and likes repel. So if you have two bar magnets with their ends marked "north" and "south," then the north end of one magnet will attract the south end of the other. On the other hand, the north end of one magnet will repel the north end of the other (and similarly, south will repel south).

Inside an electric motor, these attracting and repelling forces create rotational motion.

In the above diagram, you can see two magnets in the motor: The armature (or rotor) is an electromagnet, while the field magnet is a permanent magnet (the field magnet could be an electromagnet as well, but in most small motors it isn't in order to save power).

Electromagnets and Motors:

An electromagnet is the basis of an electric motor. You can understand how things work in the motor by imagining the following scenario. Say that you created a simple electromagnet by wrapping 100 loops of wire around a nail and connecting it to a battery. The nail would become a magnet and have a north and south pole while the battery is connected.

Now say that you take your nail electromagnet, run an axle through the middle of it and suspend it in the middle of a horseshoe magnet as shown in the figure below.

If you were to attach a battery to the electromagnet so that the north end of the nail appeared as shown, the basic law of magnetism tells you what would happen: The north end of the electromagnet would be repelled from the north end of the horseshoe magnet and attracted to the south end of the horseshoe magnet.

The south end of the electromagnet would be repelled in a similar way. The nail would move about half a turn and then stop in the position shown.

You can see that this half-turn of motion is simply due to the way magnets naturally attract and repel one another.

The key to an electric motor is to then go one step further so that, at the moment that this half-turn of motion completes, the field of the electromagnet flips.

The flip causes the electromagnet to complete another half-turn of motion.

You flip the magnetic field just by changing the direction of the electrons flowing in the wire (you do that by flipping the battery over).

If the field of the electromagnet were flipped at precisely the right moment at the end of each half-turn of motion, the electric motor would spin freely.

MAKING DIRECT CURRENT ELECTRICITY-Lesson-2

2007-07-22T20:21:00.000+05:30

A current flowing through the conductor establishes a magnetic field around the conductor. This effect works both way so that the conductor will flow in a conductor which is moved through a magnetic field.

You ca easily demonstrate electromagnetic current generation with a coil of wire and a small magnet.

Connects the leads of the coil to a meter designed to sense microamperes.

Insert a steel nail through the coil and stroke the magnet back and forth across the coil. The meter will indicate a few microamperes each stroke.

The polarity of the current will reverse on the back strokes.

Want a readymade generator????

Just rotate the shaft of a small DC motor. Most such motors produce a potential difference of up to several volts….You can add a propeller to make a wind powered generator…

MAKING DIRECT CURRENT ELECTRICITY-Lesson-1

2007-07-12T13:23:00.000+05:30

A surprising number of ways exist for producing direct current....

here is the first one....

CHEMICAL GENERATORS- Electrolytes are chemical solutions that contain many ions..

for eg.. dissolve table salt in water and the salt will break down into positive sodium ions and negative chlorine ions..

If two dissimilar metal plates are immersed in the salt solution, the positive ions will migrate toward one plate and the negative ions will migrate towards the other..

(LED is placed on a silver coin)

if the two plates are connected togather by a conductor, a current will flow through the solution ( as ions) and through the conductor (as electrons).

This kind of generator is called a wet cell.Cells in which the electrolyte is absorbed by paper or formed into a paste are called dry cells.

Some chemical generators are shown in pictures above...

Connect two or more cells in series to form a battery with total voltage equal to sum of cell voltages..

hope u guys liked it..more lessons to come in future...

Parallel Port- Robotics

2007-06-26T13:53:00.001+05:30

Parallel Port :

What is Parallel Port ? Why is it needed ?

Parallel port is used for short distance communication since no. of wires are required and many no.of bits are send at a time.

(Just turn ur C.P.U.and u will see a 25 pin female port. This is the parallel port.)We use parallel port(printer port) because other than monitor we don’t have any output devices.

That’s why we remove the printer and moreover the pins in this port generates pulses which help in the functioning of stepper motor and we have to use them for short range communication.

How to access parallel port pins in the software.

Parallel port is assigned a unique I/O address which is generally among the following:

i) 378h (mostly the case)

ii) 278h (normally found when there are more than one parallel ports)

iii)3BCh (Rare case)

The original IBM-PC's Parallel Printer Port had a total of 12 digital outputs and 5 digital inputs accessed via 3 consecutive 8-bit ports in the processor's I/O space.

See fig. on top

S- Status pins,
C- Control pins,
D- Data pins

I/O Port Access in Turbo C, Borland C/C++

Turbo C and Borland C/C++ provide access to the I/O ports on the 80x86 CPU via the predefined functions inportb / inport and outportb / outport.

int inportb(int portid); /* returns a byte read from the I/O port portid */

int inport(int portid); /* returns a word read from the I/O port portid */

void outportb(int portid, unsigned char value); /* writes the byte value to the I/O port portid */

void outport(int portid, int value); /* writes the word value to the I/O port portid */

How do Microprocessors work??Lesson-4

2007-06-11T17:23:00.000+05:30

Step 4: Push Key =

(A)When you press the "=" key, the Prefetch Unit once again checks the Instruction Cache for an instruction for the new data, which it doesn't find.

(B)The instruction for "=" comes into the microprocessor from the computer's main memory through the Bus Unit and gets stored in an Instruction Cache address as the code "Print Z."

(C)The Prefetch Unit then asks the Instruction Cache for a copy of the code "Print Z" and sends it to the Decode Unit for further processing.

(D)In the Decode Unit, the instruction "Print Z" is translated or decoded into a string of binary code that is sent off to the Control Unit to tell it what to do with the instruction.

(E)Now that the value of Z has been computed, and is residing in register file entry #5, the print command has only to retrieve register 5's contents and display them to a screen so you can finally see the sum of 2+3. The microprocessor has completed its task for you.

How do Microprocessors work??? Lesson-3

2007-06-09T22:24:00.000+05:30

Step 3: Push Key +

(A)When you press the "+" key the Prefetch Unit asks the computer's main memory and Instruction Cache for instructions on the new data, which must be fetched from main memory.

(B)Because this is a new instruction, the "+" comes into the microprocessor from the computer's main memory and gets stored at an address in the Instruction Cache as a code "X+Y=Z," showing that the act of adding is going to take place.

(C)The Prefetch Unit then asks the Instruction Cache for a copy of the code "X+Y=Z" and sends it to the Decode Unit for further processing.

(D)In the Decode Unit, "X+Y=Z" is translated or decoded and sent off to the Control Unit and the Data Cache to tell them what to do with the instruction-also the ALU is given a message that an ADD function will be performed.

(E)In the Control Unit, the code is broken down and the ADD command is sent to the ALU where "X" and "Y" are added together after they have been sent up from the Data Cache. The ALU then talks to its buddy, the Registers, and sends the "5" over to be stored in one of the address locations there.

How do Microprocessors work??? Lesson-2

2007-06-07T18:54:00.000+05:30

Step 2:
Push Key 3

(A)When you press the 3 key, the Prefetch Unit asks the computer's main memory and the Instruction Cache for specific instructions on this new data. No matching instruction is found in the Instruction Cache so the instruction will come from the main memory.

(B)Similar to "2=X," the new data instructions come into the microprocessor from the computer's main memory and get stored in an Instruction Cache address where it is assigned the code "3=Y."

(C)The Prefetch Unit then pulls a copy of the code "3=Y" from the Instruction Cache and sends it to the Decode Unit for further processing.

(D)In the Decode Unit the instruction "3=Y" is translated or decoded into a string of binary code that is sent off to the Control Unit and the Data Cache to tell them what to do with the instruction.

(E)Because the Decode Unit figured out that the number 3 was to be stored for the future in the Data Cache, the Control Unit now performs the instruction for "3=Y." This causes the number 3 to be sent to an address in the Data Cache called "Y," where it waits like the "2" for further orders.

How do Microprocessors work?? Lesson 1

2007-06-05T21:11:00.000+05:30

INTRODUCTION:

Today's microprocessors are the brains of your personal computer. Here on this tiny silicon chip are millions of switches and pathways that help your computer make important decisions and perform helpful tasks. And microprocessors don't just think for computers-you might find a processor in many other everyday items like your telephone or car. To help you understand how the microprocessor does its job, you will go step by step through a simple task on the chip. For the purpose of this demonstration, you will add two numbers together while watching the microprocessor do its magic. You will complete this task in four easy steps and you may review each step as many times as you want. Remember, each part of the processor has a special task.

Step 1:

Push Key 2

(A)Pressing the 2 key alerts the microprocessor and signals the Prefetch Unit to ask the computer's main memory for a specific instruction on the new data since there is nothing about it in the Instruction Cache.

(B)The new data instruction comes into the microprocessor through the Bus Unit from the computer's main memory and gets stored in the Instruction Cache, where it is assigned a code "2=X".

(C)The Prefetch Unit then asks the Instruction Cache for a copy of the code "2=X" and sends it to the Decode Unit for further processing.

(D)In the Decode Unit the instruction "2=X" is translated or decoded into a string of binary code that is sent off to the Control Unit and the Data Cache to tell them what to do with the instruction.

(E)Because the Decode Unit figured out that the number 2 was to be stored for the future in the Data Cache, the Control Unit now performs the instruction for "2=X." This causes the number 2 to be sent to an address in the Data Cache called "X," where you see it waiting for further orders.

3 more lessons to come in future posts ..bew in touch guys................

2007-06-02T20:07:00.000+05:30

VLF TECHNOLOGY

Very low frequency (VLF), also known as induction balance, is probably the most popular detector technology in use today. In a VLF metal detector, there are two distinct coils:

· Transmitter coil - This is the outer coil loop. Within it is a coil of wire. Electricity is sent along this wire, first in one direction and then in the other, thousands of times each second. The number of times that the current's direction switches each second establishes the frequency of the unit.

· Receiver coil - This inner coil loop contains another coil of wire. This wire acts as an antenna to pick up and amplify frequencies coming from target objects in the ground.
The current moving through the transmitter coil creates an electromagnetic field, which is like what happens in an electric motor. The polarity of the magnetic field is perpendicular to the coil of wire. Each time the current changes direction, the polarity of the magnetic field changes. This means that if the coil of wire is parallel to the ground, the magnetic field is constantly pushing down into the ground and then pulling back out of it.

As the magnetic field pulses back and forth into the ground, it interacts with any conductive objects it encounters, causing them to generate weak magnetic fields of their own. The polarity of the object's magnetic field is directly opposite the transmitter coil's magnetic field. If the transmitter coil's field is pulsing downward, the object's field is pulsing upward.

The receiver coil is completely shielded from the magnetic field generated by the transmitter coil. However, it is not shielded from magnetic fields coming from objects in the ground. Therefore, when the receiver coil passes over an object giving off a magnetic field, a small electric current travels through the coil. This current oscillates at the same frequency as the object's magnetic field. The coil amplifies the frequency and sends it to the control box of the metal detector, where sensors analyze the signal.

The metal detector can determine approximately how deep the object is buried based on the strength of the magnetic field it generates. The closer to the surface an object is, the stronger the magnetic field picked up by the receiver coil and the stronger the electric current generated. The farther below the surface, the weaker the field. Beyond a certain depth, the object's field is so weak at the surface that it is undetectable by the receiver coil.

How does a VLF metal detector distinguish between different metals? It relies on a phenomenon known as phase shifting. Phase shift is the difference in timing between the transmitter coil's frequency and the frequency of the target object. This discrepancy can result from a couple of things:

· Inductance - An object that conducts electricity easily (is inductive) is slow to react to changes in the current. You can think of inductance as a deep river: Change the amount of water flowing into the river and it takes some time before you see a difference. Resistance - An object that does not conduct electricity easily (is resistive) is quick to react to changes in the current. Using our water analogy, resistance

· Resistance - An object that does not conduct electricity easily (is resistive) is quick to react to changes in the current. Using our water analogy, resistance would be a small, shallow stream: Change the amount of water flowing into the stream and you notice a drop in the water level very quickly.

Basically, this means that an object with high inductance is going to have a larger phase shift, because it takes longer to alter its magnetic field. An object with high resistance is going to have a smaller phase shift.

Phase shift provides VLF-based metal detectors with a capability called discrimination. Since most metals vary in both inductance and resistance, a VLF metal detector examines the amount of phase shift, using a pair of electronic circuits called phase demodulators, and compares it with the average for a particular type of metal. The detector then notifies you with an audible tone or visual indicator as to what range of metals the object is likely to be in.

Many metal detectors even allow you to filter out (discriminate) objects above a certain phase-shift level. Usually, you can set the level of phase shift that is filtered, generally by adjusting a knob that increases or decreases the threshold. Another discrimination feature of VLF detectors is called notching. Essentially, a notch is a discrimination filter for a particular segment of phase shift. The detector will not only alert you to objects above this segment, as normal discrimination would, but also to objects below it.

Advanced detectors even allow you to program multiple notches. For example, you could set the detector to disregard objects that have a phase shift comparable to a soda-can tab or a small nail. The disadvantage of discrimination and notching is that many valuable items might be filtered out because their phase shift is similar to that of "junk." But, if you know that you are looking for a specific type of object, these features can be extremely useful.

METAL DETECTORS

2007-05-31T20:19:00.000+05:30

Introduction:

Metal-detector technology is a huge part of our lives, with a range of uses that spans from leisure to work to safety. The metal detectors in airports, office buildings, schools, government agencies and prisons help ensure that no one is bringing a weapon onto the premises. Consumer-oriented metal detectors provide millions of people around the world with an opportunity to discover hidden treasures

Details:

A typical metal detector is light-weight and consists of just a few parts:

· Stabilizer (optional) - used to keep the unit steady as you sweep it back and forth
· Control box - contains the circuitry, controls, speaker, batteries and the microprocessor
· Shaft - connects the control box and the coil; often adjustable so you can set it at a comfortable level for your height
· Search coil - the part that actually senses the metal; also known as the "search head," "loop" or "antenna"

Most systems also have a jack for connecting headphones, and some have the control box below the shaft and a small display unit above.

Operating a metal detector is simple. Once you turn the unit on, you move slowly over the area you wish to search. In most cases, you sweep the coil (search head) back and forth over the ground in front of you. When you pass it over a target object, an audible signal occurs. More advanced metal detectors provide displays that pinpoint the type of metal it has detected and how deep in the ground the target object is located.

Metal detectors use one of three technologies:
· Very low frequency (VLF)
· Pulse induction (PI)
· Beat-frequency oscillation (BFO)

In my future blogs i will be posting all these technologies in detail...

so be in touch....

SOLID PROPELLENT ROCKETS

2007-05-18T19:46:00.000+05:30

INTRODUCTION

ROCKET, general term for a jet propulsion device propelled by the expulsion of gases generated in a combustion chamber. Since the combustible propellants contain both fuel and an oxidizer, a rocket develops thrust independent of its surroundings, unlike other types of jet engines that utilize oxygen from the atmosphere to burn fuel carried aboard. A rocket engine, therefore, is self-contained and is the only type of device suitable for flight propulsion into outer space.

Thrust to propel a rocket is based on Isaac Newton's third law of motion (see Mechanics), which states that for every action, there is an equal and opposite reaction.
The amount of thrust developed by a rocket motor depends mainly on two factors, the velocity with which the burning gases leave the combustion chamber, and the mass of the burning gases.

The term rocket has frequently been used to describe both the thrust-producing device and the whole rocket-powered vehicle. To avoid confusion, especially in the case of large vehicles such as missiles and space-launch vehicles, we also call the propulsion device as a rocket engine.

SOLID PROPELLENT ROCKET:

Early solid-propellant rockets were powered by the combustion of a mixture containing the same ingredients as black gunpowder, but in different proportions.
Gunpowder - 75 % saltpetre,
12 % sulphur,
13 % charcoal by weight.
Rocket charges consisted of - 60 % saltpetre,
15 % sulphur,
25 % charcoal.
Because of this different composition, the rocket charge burned more slowly than gunpowder.

The principal parts of the solid-propellant rocket are
(i) payload(consisting of the warhead or scientific instruments)
(ii) combustion chamber, or motor( containing the fuel charge and nozzles to expel the combustion gases) Fins may be added to stabilize its flight.

Solid-propellant rockets today are divided into two categories,
(i)those with unrestricted burning charges
(ii) with restricted burning charges, known also as wall-fitting charges.

An unrestricted burning charge also may be shaped in the form of a thick-walled hollow tube, which burns at both its inside and outside surfaces. No matter what its size or shape, the charge is called a grain and the devices that hold it in place are known as traps. Unrestricted burning charges have burning times of less than one sec.

For longer burning times a wall-fitting charge is used. This type of charge either burns across its cross section, or it may be hollowed out at the centre so that it burns from the inside towards the rocket wall. The latter method permits a reduction in the thickness of the wall of the outer metal tube of the rocket, because for virtually all of the burning time, the metal tube is reinforced by what is left of the charge.

Modern solid-propellant charges are of very large size. For example, the take-off weight of the solid-propellant submarine-launched Trident-II D5 missile is about 59,000 kg . The two solid rocket boosters (SRBs) on the space shuttle weigh more than half a million kg each. Made of 11 steel segments, the SRB is the largest solid-propellant rocket ever built in the United States. As a result of the Challenger space shuttle disaster, the seals between the segments were redesigned to prevent a recurrence of the problem that caused the destruction of the spacecraft.

LIGHT PENS

2007-05-10T20:58:00.000+05:30

Hey guys, after a lot of theory lets hop on to some technical advancements...

U can see a light pen in the above pic. wanna know about light pen????

given below are the details of this pen!!!

Light Pen, a pointing device in which the user holds a wand, which is attached to the computer, up to the screen and selects items or chooses commands on the screen either by pressing a clip on the side of the light pen or by pressing the light pen against the surface of the screen.

The wand contains light sensors and sends a signal to the computer whenever it records a light, as during close contact with the screen when the non-black pixels beneath the wand's tip are refreshed by the display's electron beam.

The computer's screen is not all lit at once—the electron beam that lights pixels on the screen traces across the screen row by row, all in the space of 1/50 of a second.its hard to imagine.. right???

By noting exactly when the light pen detected the electron beam passing its tip, the computer can determine the light pen's location on the screen.

The light pen doesn't require a special screen or screen coating, as does a touch screen, but its disadvantage is that holding the pen up for an extended length of time is tiring to the user.

Light pens are often used in computer-aided design and computer-aided manufacture (CAD and CAM) technology because of the flexibility they provide.

what a wonderful invention.. isn't it??????

CAPACITOR

2007-04-26T18:08:00.000+05:30

Hi guys,it has been a long time since my last topic. Well I was busy with my submissions and prelims in college.. Now today as I got time I am back with a new topic. Hope u get a good picture of capacitor by this post.. so here it is……….

CAPACITOR:

In a way, a capacitor is a little like a battery. Although they work in completely different ways, capacitors and batteries both store electrical energy.

A battery has two terminals. Inside the battery, chemical reactions produce electrons on one terminal and absorb electrons at the other terminal.

A capacitor is a much simpler device, and it cannot produce new electrons -- it only stores them.

Like a battery, a capacitor has two terminals. Inside the capacitor, the terminals connect to two metal plates separated by a dielectric. The dielectric can be air, paper, plastic or anything else that does not conduct electricity and keeps the plates from touching each other. You can easily make a capacitor from two pieces of aluminum foil and a piece of paper. It won't be a particularly good capacitor in terms of its storage capacity, but it will work.

When you connect a capacitor to a battery, here’s what happens:
The plate on the capacitor that attaches to the negative terminal of the battery accepts electrons that the battery is producing.
The plate on the capacitor that attaches to the positive terminal of the battery loses electrons to the battery.

Once it's charged, the capacitor has the same voltage as the battery (1.5 volts on the battery means 1.5 volts on the capacitor). For a small capacitor, the capacity is small. But large capacitors can hold quite a bit of charge. You can find capacitors as big as soda cans, for example, that hold enough charge to light a flashlight bulb for a minute or more. When you see lightning in the sky, what you are seeing is a huge capacitor where one plate is the cloud and the other plate is the ground, and the lightning is the charge releasing between these two "plates." Obviously, in a capacitor that large, you can hold a huge amount of charge!

Here you have a battery, a light bulb and a capacitor. If the capacitor is pretty big, what you would notice is that, when you connected the battery, the light bulb would light up as current flows from the battery to the capacitor to charge it up. The bulb would get progressively dimmer and finally go out once the capacitor reached its capacity. Then you could remove the battery and replace it with a wire. Current would flow from one plate of the capacitor to the other. The light bulb would light and then get dimmer and dimmer, finally going out once the capacitor had completely discharged (the same number of electrons on both plates).

The difference between a capacitor and a battery is that a capacitor can dump its entire charge in a tiny fraction of a second, where a battery would take minutes to completely discharge itself. That's why the electronic flash on a camera uses a capacitor -- the battery charges up the flash's capacitor over several seconds, and then the capacitor dumps the full charge into the flash tube almost instantly. This can make a large, charged capacitor extremely dangerous -- flash units and TVs have warnings about opening them up for this reason. They contain big capacitors that can, potentially, kill you with the charge they contain.

FARADS:

the unit of capacitance is a farad. A 1-farad capacitor can store one coulomb (coo-lomb) of charge at 1 volt. A coulomb is 6.25e18 (6.25 * 10^18, or 6.25 billion billion) electrons. One amp represents a rate of electron flow of 1 coulomb of electrons per second, so a 1-farad capacitor can hold 1 amp-second of electrons at 1 volt.

A 1-farad capacitor would typically be pretty big. It might be as big as a can of tuna or a 1-liter soda bottle, depending on the voltage it can handle. So you typically see capacitors measured in microfarads (millionths of a farad).

To get some perspective on how big a farad is, think about this:

A typical alkaline AA battery holds about 2.8 amp-hours.

That means that a AA battery can produce 2.8 amps for an hour at 1.5 volts (about 4.2 watt-hours -- a AA battery can light a 4-watt bulb for a little more than an hour).

Let's call it 1 volt to make the math easier. To store one AA battery's energy in a capacitor, you would need 3,600 * 2.8 = 10,080 farads to hold it, because an amp-hour is 3,600 amp-seconds.

If it takes something the size of a can of tuna to hold a farad, then 10,080 farads is going to take up a LOT more space than a single AA battery! Obviously, it is impractical to use capacitors to store any significant amount of power unless you do it at a high voltage.
Capacitors are used in several different ways in electronic circuits:

Sometimes, capacitors are used to store charge for high-speed use. That's what a flash does. Big lasers use this technique as well to get very bright, instantaneous flashes.

Capacitors can also eliminate ripples. If a line carrying DC voltage has ripples or spikes in it, a big capacitor can even out the voltage by absorbing the peaks and filling in the valleys.

TALON- The Military Robot

2007-03-22T15:11:00.001+05:30

TALON Robots: Speed, Simplicity, Standoff

TALON robots are powerful, durable, lightweight tracked vehicles that are widely used for explosive ordnance disposal (EOD), reconnaissance, communications, hazmat, security, defense and rescue. They have all-weather, day/night and amphibious capabilities and can navigate virtually any terrain.

How are they different from other robots on the market?

1. Man-portable -- At less than 100 lb (45 kg), TALON can be easily transported and is instantly ready for operation.

2. Rugged -- TALON robots can take a punch and stay in the fight. One was blown off the roof of a Humvee in Iraq recently while the Humvee was crossing a bridge over a river. TALON flew off the bridge and plunged into the river below. Soldiers later used its operator control unit to drive the robot back out of the river and up onto the bank so they could retrieve it.

3. Fast -- TALON is the fastest robot on the market today with seven speed settings.

4. High payload capacity -- Long-term system versatility optimizes investment. TALON has the highest payload capacity and payload-to-weight ratio, allowing for the incorporation of a broad array of sensor packages.

5. Mobile -- Climbs stairs, negotiates rock piles, overcomes concertina wire, plows through snow and surf.

6.Intuitive -- Easiest robot to operate; joystick controls.
Withstand repeated decontamination -- Demonstrated at Ground Zero after 2001 World Trade Center attack in New York City. Electronics withstood 45 straight days of being decontaminated twice a day without failing.

7.Long battery life -- TALON robots have the longest battery life of all man-portable robots.

ORG's 2nd workshop,,,,

2007-02-20T16:29:00.000+05:30

hi friends,
After the success of the workshop held on 4th feb07, OM Robotics Group is organising its second workshop on 25th feb07, ie Sunday.

We will be providing u with all the materials required to build an efficient robot.There will be theory lectures on robotics and presentation...
.the topics covered will be..gears,dc motors, repairing of motors,forward and rearwheel drives, different designs and how to club all designs in a single design,problems arising in level 1 and there solutions,etc etc

the charges are too low...they r
650/- Rs per head for 2 members in a team.
550/-Rs per head for 3 members in a team.
450/-Rs per head for 4 members in a team.
400/- RS per head for 5 members in a team.
u can check out our authors blog www.roboticera.blogspot.com and
check out the pics of our last workshop on www.omrobotics.blogspot.com

for furtherdetails call
Mohit -9869723502
Kshitiz-9969130874
Saurabh-9820318680

U just have to hop in empty handed and will go back with a robot(level1)

ROBOTICS LEVEL-1 WORKSHOP

2007-01-28T15:01:00.000+05:30

Hi friends,

Good news for u guys!!!!!!
I am organising a workshop on Robotics level-1 on 4th Feb, Sunday in Nerul, Navi Mumbai
Here are the details...

The topics that will be covered are

About motors and repairing of motors.
• Mechanics of a robot
• How to locate a C.G of a robot.
• Theory and practical of gears and uses.
• Latest trends and how can we make robots of daily uses.
• How to make a remote control robot.{ practical involved}
• Slides on robotics.

• Designing of any kind of robot.………………… and many more.
In this workshop many topics will be covered and this is open for all.
All the material required to make a robot will be provided by the organizers.
This is going to be a 4 hr. workshop.
You just have to hop in empty handed and u will go back with a remote control robot.
Notes on how to make a remote control robot will also be provided.

The charges .
1 member in a team – Rs. 1000/-
2 members in a team --- Rs. 1200/-
3 members In a team-- Rs. 1500/-
4 members in a team-- Rs. 1600/-
The last day for registration is decided to be 30th Jan.
so u guys get 3 more days to register.So register as soon as possible.
Since it has to be clear how many teams are there exactly, so that we can arrange for that much material.
Lets make it a success…..

ROBOT SENSORS

2007-01-14T11:28:00.001+05:30

{ii} {iii} {iv}

{i}

Bumper Switches :{fig i}

Switchs are probably the simplest sensor to use on a robot. They can detect collisions, limit travel, even detect dropoffs. Their use is almost a requirement to backup other sensors that may fail. Putting them together just involves bolting them down and providing enough of a lever to actuate them easily. Builders have added length to the lever already there or even placed a balanced ring around several for a circular bumper around the robot. Drop detectors would have feelers beneath the robot sliding across the floor. Very simple operation which allows for reliable detection, what every robot needs.

CdS Cells :{fig.ii}

Another simple sensor for robots uses the light sensitivity of Cadium Sulfide or CdS cells. These change resistance based on the intensity of light shining on them. In the dark, they can be in the 100s or more of kohms. In light, they can be less than 1k. Their use would be in a resistive divider between 5 volts and ground, either as the top or bottom with the output between the CdS cell and the current limiting resistor. This would provide a highly variable analog signal to a controller, which could cause irregular switching. If the controller supports it, an analog input could be used to read these, or if not, an analog to digital converter (ADC) or a comparator could make the input more usable. These work well for finding light and dark areas or in line detection in line following robots.

Infra Red Sensors :{fig.iii}

InfraRed sensor circuits have many varieties. The simplest uses an IR LED to deliver the light and an IR sensitive phototransistor to see it. The phototransistor turns on when IR light hits it, whether from the LED or ambient sources or reflected. The circuit shown should deliver an output if any IR light shines on it. Typical values for the resistor going to the phototransistor collector would be around 10K ohms or so. LEDs are usually driven through 200 to 1K ohm resistors. When no IR light is can be seen by the detector, you should see a good high (5 volt) from the output connected to the collector. When IR light is present, the phototransistor should conduct and you should see a good low, probably around 0.7 volts. One simple use might involve line detection, with sensors on either side and on a line to be followed by the robot.
More sophisticated IR usage involves pulsing IR light at a known frequency, and using a detector that is attuned to that frequency. The circuitry within the Sharp GP1U58Y series tunes the detector to a specific frequency. Each is sensitive to IR that has been pulsed at that given frequency in short bursts. This encoding of the IR helps to mask out external sources that might have been in the way of information we really want, specifically how close something is or the recieving of coded data. What is needed for proximity detection is an IR source that outputs light at the specified frequency and on time for that freqency to match the detectors reception charecteristics. Various circuits work, from 555 timers that drive the IR LEDs to simply hooking them to lines from your controller and programming in the appropriate driving sequence. My use has been with Dennis Clarks IR proximity detector, based on the DPRG IR proximity detector by Jeff Koenig. This circuit uses a PIC to generate the appropriate frequency and pulsing for left and right IRs, counts the number of detections for each side and finally outputs a good dectection for either the left or right side. Doing this all on a seperate processor frees up the controller for other tasks in driving a robot. It can use the Sharp detector, a Radio Shack LiteOn detector, or a Panasonic PNA4601M series. I've used both the Sharp and the Panasonic PNA4602M. The board provides excellent right and left detections, and is only confused in rooms with high flourescent lighting. In these I plan to try the little trick of using a small strip of exposed film or perhaps some of the red plastic for remotes in front of the detector to hopefully shield some of the flourescent "noise" that overloads it.

More advanced infrared sensors come in "all in one" packages, such as the Sharps GP2Dxx series. These sensors can provide range information, in either analog or digital form, or simply be a trigger point when something is within an adjustable range. The GP2D02 gives an 8 bit digital reading when triggered. GP2D05s give an high or low signal when a specific preset range is reached. GP2D12s output an analog voltage corresponding to range continuously. GP2D15s output a high or low when crossing a 9.5" distance. All typically have detection capabilities from 4" to 31" and cost anywhere from $13 to $25, depending on capabilities.
IRLED phototransistor pairs can be used for encoders. Either a reflective pair which can count strips on a wheel or a slotted type to count slits in a wheel are possible. Several different types exist, usually in the form of quadrature encoders. Quadrature encoders use 2 pairs of sensors which are placed out of sequence with each other to allow knowing the direction a motor is turning, as well as how far or fast it is going. Some people have even hacked these from inside computer mice. One further advanced use of IR is in it's basic use in remote control. Again appropriate sequencing is needed, but information can be transmitted and received, just as you turn on and off your TV. Dennis Clark has again put this to use in an encoder/decoder pair of PICs for transmitting and receiving information. Other web pages discuss the coding sequences on regular TV remotes and provide some information as to the sequences involved. I haven't used this yet, but can see it as a great way to start your robot remotely or drive it or possibly have a data link between the robot and a computer.

Sonar :{fig.iv}

Sonar provides another method of telling your robot where things are. The Polaroid Sonar rangers have been good at providing the distance to an object through pinging a transducer and waiting for a return echo. Your controller times the period between the initial pulse and the return echo. And through a quick calculation you've got the distance to whatever the sound bounced from, based on sound traveling about 1 inch in 74 microseconds. The Polaroid modules can range from about 6 inches to 35 feet. Some folks have used modules taken from cameras and hacked for providing a signal. This allows a cheaper solution than buying a full Polaroid development kit for $40 to $70. Some sonar cameras can be had for as little as $5 through thrift stores and only require a few additional cheap parts to work. One new alternative is the sonar module put together by Devantech. The Devantech modules range is about 1 inch to 10 feet and the price is about $25. The interface is relatively simple for most controllers.

PROGRAMME ON LINE FOLLOWER ROBOT

2006-12-20T21:55:00.000+05:30

Hey guys, earlier i had posted a programm on parallel port.

here is a programme on line follower robot. check it out!!

int motl=0, motr=1;
int s=25;
int l=4, m=3, r=2;
float dt=0.0;

int l_notape,m_notape,r_notape;
int l_tape,m_tape,r_tape;
int l_tol,m_tol,r_tol,d;

void main(){
calibrate();
init();
d=3;
while(1){
if (d==3) {
while((analog(l)<=l_tol)&&(analog(m)<=m_tol)&&(analog(r)<=r_tol)){ motor(motl,s); motor(motr,-s); printf("%d %d %d\n",analog(l),analog(m),analog(r)); if (analog(l)>l_tol)
d=1;
if (analog(m)>m_tol)
d=2;
if (analog(r)>r_tol)
d=3;
}
}
while((analog(l)>l_tol)(analog(m)>m_tol)(analog(r)>r_tol)){
motor(motl,2*s);
motor(motr,2*s);
printf("%d %d %d\n",analog(l),analog(m),analog(r));
if (analog(l)>l_tol)
d=1;
if (analog(m)>m_tol)
d=2;
if (analog(r)>r_tol)
d=3;
}
printf("%d %d %d\n",analog(l),analog(m),analog(r));
if (d==1) {
while((analog(l)<=l_tol)&&(analog(m)<=m_tol)&&(analog(r)<=r_tol)){ motor(motl,-s); motor(motr,s); printf("%d %d %d\n",analog(l),analog(m),analog(r)); if (analog(l)>l_tol)
d=1;
if (analog(m)>m_tol)
d=2;
if (analog(r)>r_tol)
d=3;
}
}
}
}

/ Subroutines/

void calibrate(){
int temp;
while(!stop_button()){
l_notape=analog(l);
m_notape=analog(m);
r_notape=analog(r);
printf("No Tape: %d %d %d\n",l_notape,m_notape,r_notape);
sleep(.1);
}
tone(800.,1.);
while(!stop_button()){
l_tape=analog(l);
m_tape=analog(m);
r_tape=analog(r);
printf("Tape: %d %d %d\n",l_tape,m_tape,r_tape);
sleep(.1);
}
temp=(l_tape-l_notape)/2;
l_tol=l_notape+temp;
temp=(m_tape-m_notape)/2;
m_tol=m_notape+temp;
temp=(r_tape-r_notape)/2;
r_tol=r_notape+temp;
printf("Tol: %d %d %d\n",l_tol,m_tol,r_tol);
tone(800.,1.);
}
void init(){
printf("Press Start to Go!\n");
while(!start_button()){}
tone(800.,1.);
}
void test(){
while((analog(l)<=l_notape)&(analog(m)>=m_tape)&(analog(r)<=r_notape)){ motor(motl,s); motor(motr,s); printf("%d %d %d\n",analog(l),analog(m),analog(r)); } ao(); while (analog(l)>=l_tape){
motor(motl,-s);
motor(motr,s);
printf("%d %d %d\n",analog(l),analog(m),analog(r));
}
while (analog(r)>=r_tape){
motor(motl,s);
motor(motr,-s);
printf("%d %d %d\n",analog(l),analog(m),analog(r));
}
}

REMOTE CONTROLLED FAN REGULATOR

2006-12-15T10:15:00.000+05:30

Hi friends,here is the remote control fan regulator. Though the circuit seems to be scary, it iis not so.just go through the bulleted points and u find it damn easy.

Well... the circuit image is too small to understand. but this was the maximum size i could post. u can get a clear image by clicking on it.
Using this circuit, u can change the speed of the fan from ur bed.

Infrared receiver module TSOP1738 is used to recieve the infrared signal transmitted by remote control.
The circuit is powered by regulated 9V. The AC mains is stepped down by transformer X1 to deliever a secondary output of 12V-0-12V.
The transformer output is rectified by full wave rectifier comprising diodes D1 and D2, filtered by capacitor C9 and regulated by 7809 regulator to provide 9V regulated output.
Any button on the remote can be used for controlling the speed of the fan.Pulses from the IR reciever module are appllied as a trigger signal to timer NE555{IC1} via LED1 and resistor R4.
IC1 is wired as a monostable multivibrator to delay the clock given to decade counter-cum-driver IC CD4017{IC2}.
Out of the ten outputs of the decade counter IC2{Q0 through Q9}, only five{Q0 through Q4} are used to control the fan. Q5 output is not used, while Q6 output is used to reset the counter.
Another NE555 timer{IC3} is also wired as a monostable multivibrator.Combination of one of the resistors R5 through R9 and capacitor C5 controls the pulse width.
The output from IC CD4017{IC2} is applied to resistors R5 through R9.If Q0 si high capacitor C5 is charged through resistor R5, if Q1 is high capacitor C5 is charged through resistor R6, and so on.
Optocoupler MCT2E{IC5} is wired as a zero-crossing detector that supplies trigger pulses to monostable multivibrator IC3 during crossing.
Opto-isolator MOC3021{IC4} drives triac BT136.
REsistor R13{47 ohms} and capacitor C7{0.01microfarad} combination is used as snubber network for triac 1 {BT136}.
As the width of the pulse decreases,firing angle of the triac increases and speed of fan also
increases. Thus the speed of fan increses when we press any button on the remote control.
u can assemble the circuit on a general purpose PCB and put it in a small case such that the infrared sensor can easily recieve the signal from remote transmitter.

SENSORS

2006-12-08T10:24:00.001+05:30

What are Sensors?

Sensors are devices that provide an interface between electronic equipment and the physical world. They Help electronics to "see," "hear," "smell," "taste," and "touch" the physical world by converting input objective physical or chemical signals into electrical signals.

How are sensors classified?

There are many sorts of categorization methods available. The most popular way is based upon the kinds of the targeted signals to be sensed. Roughly, there are six signal domains and related sensors.
The thermal signal domain: the most common signals are temperature, heat flux, or heat flow. Related sensors are called thermal signal sensors.
The mechanical signal domain: the most common signals are force, pressure, velocity, acceleration, and position. Related sensors are called mechanical signal sensors.
The chemical signal domain: the signals are the internal quantities of the matter such as concentration of a certain material, composition, or reaction rate. Related sensors are called chemical signal sensors.
The magnetic signal domain: the most common signals are magnetic field intensity, flux density, and magnetization. Related sensors are called magnetic signal sensors.
The radiant signal domain: the signals are quantities of the electromagnetic waves such as intensity, wavelength, polarization, and phase. Related sensors are called radiant signal sensors.
The electrical signal domain: the most signals are voltage, current, and charge. Related sensors are called electrical signal sensors.

How to Parameterize a Sensor

Absolute sensitivity - the ratio of the change of output signal to the change of the measured (physical or chemical quantity)
Relative sensitivity - the ratio of a change of the output signal to a change in the measurand normalized by the value of the output signal when the measurand is zero.
Cross sensitivity - the change of the output signal caused by more than one measurand.
Direction dependent sensitivity - a dependence of sensitivity on the angle between the measurand and the sensor.
Resolution - the smallest detectable change in the measurand that can cause a change of the output signal.
Accuracy - the ratio of maximum error of the output signal to the full-scale output signal expressed in a percentage.
Linearity error - the maximum deviation of the calibration curve of the output signal from the best-fitted straight line that describes the output signal.
Hysteresis - a lack of the sensor’s capability to show the same output signal at a given value of measurand regardless of the direction of the change in the measurand.
Offset - the output signal of the sensor when measurand is zero.
Noise - the random output signal not related to the measurand.
Cutoff frequency - the frequency at which the output signal of the sensor drops to 70.7% of its maximum.
Dynamic range - the span between the two values of the measurand (maximum and minimum) that can be measured by sensor.
Operating temperature range - the range of temperature over which the output signal of the sensor remains within the specified error.

The Broad Applications of Sensors:

Factory Automation-Computer, Automobile, Environmental Monitoring, Industry Monitoring, Telecommunication, Transportation, Health Care, Space Exploration, and Military Uses indicate that sensors can be used in almost every aspect of our life.

As more and more advanced technology brings numerous opportunities for human beings to pursue better quality of life and explore new living space, the importance of accurate, reliable, fast and economic approaches to better existing technology solutions are based upon more precise control of machines and devices. Signal technology is becoming more and more crucial for all these attempts. This is the basis of a rapid boost in the sensor industry. New sensor technology brings new dimensions to emerging products in the form of convenience, energy savings, and safety. Sensors are the machinerized eyes, ears, noses, and nerves we use to touch the world around us. They are applied to a tremendous variety of fields and are influencing our life in previously unimagined ways.

How Does a Sensing System Work?

Primary Sensor System

look at the block diagram above.

the second diag is not clear it goes like this

-> input transducer ---> Signal processing--->output transducer-->

BEGINNER TO ROBOTICS-III (CIRCUIT)

2006-12-01T11:14:00.000+05:30

Hi Guys,

I hope the funda of C.G location, drives, gears,etc is clear from the past two chapters.
Now lets begin with the 3rd chapter ie. The circuitry of a normal robotic car.
This circuitry will enable the robo to move forward, backward, left and right.

Now starting with circuitry we need 2 two way switches. These switches conduct in both directions hence the name two way switches.

Firstly we sort the terminals

1 and 6 { first switch}

2 and 5 { “ }

1’ and 6’ { second switch}

2’ and 5’ { “ }

Then we choose the terminals of first switch ie. 5 as positive or 6 as positive . either way one wants to, can do so.
But one thing has to be kept in mind that if 5 is positive in 1st switch then 5’ should be the + ve terminal of 2nd switch.
The same convention for negative terminal.

POWER SUPPLY

Terminals 3,4 from 1st switch and terminals 3’, 4’ from 2nd switch are the power supply terminals.
In this too we have to use the same convention like the +ve and –ve terminals of either switches.
If we take 3 as +ve than we have to take 3’ as +ve and give this combined combination to the powe supply as +ve.
The same case for negative ie. Combination of 4 and 4’ for negative.
Or the reverse can also be done.

The terminals 3 and3’ are sorted with the help of wires and similarly we sort the terminals 4 and 4’.
The output single wire from 3 and 3’ combination will be given to + ve of the power supply and the output single wire from the combination of 4 and 4’ will be given to the – ve of the power supply.

Power supply can be an adaptor or an eliminator of 12 volts.

This is the connection we make in switch. Now how to proceed with combining this connection with motors.

MOTOR CONNECTION

We will call the top and bottom motors on left hand side the left pair and
The top an bottom motors on right side the right pair
The above picture shows the left pair . similarly we have to connect the right pair.

LEFT PAIR MOTORS

We will bring together the positive of both the top and bottom motor on left hand side and sort them . similarly we will sort the negative of both the motors of the left pair.
RIGHT PAIR MOTORS
Now as we did in the left pair we will sort the +ve wire of both motors together and sort the –ve of the motors .

So in all we get 4 output wires from the motor connection .
2 from left pair and 2 from right pair.

COMBINING THE SWITCH AND MOTOR CIRCUIT

Now to connect the switch to motors we have to choose four output from the switch connection as we have four output from the motor connection.

We will consider the terminal 5 and 6 from the first switch and 5’ and 6’ from second switch.
Considering the terminal 5 from first switch positive terminal 5’ will be positive from second switch. Similarly 6 and 6’ are considered as negative.

Now the connection goes this way

positive wire combination from left pair motors will be connected to point 5
negative wire combination from left pair motors will be connected to point 6
positive wire combination from right pair will be connected to point 5’
negative wire combination from right pair will be connected to point 6’

these connections are made with the help of intermediate wires called the rainbow wires. I suppose…..
these are a bunch of thin wires used for internal circuitry.

If suppose u connect positive wire from left hand pair from motors to red wire then the other end of red wire will be connected to point 5.
Similarly for all connections.

The length of the intermediate wire depends on the user. Normally we take 8 to 9 meters. That will be the range of your robo.

Worlds Largest Diamond Mine

2006-11-30T19:34:00.000+05:30

Hi Guys,

check out the worlds largest DIAMOND mine.

The red spot which u see in the third pic is actually a jumbo truck.

This diamond mine in eastern Siberia is so deep that the surrounding air zone is closed for helicopters as there were some cases of helicopters getting sucked in by downward airflow...

Regarding the third lesson of robotics it will be coming in another 2 to 3 days. actually i could not arrange for the circuit diagrams.

never mind it will be coming soon.

BEGINNER TO ROBOTICS- II

2006-11-19T17:32:00.000+05:30

Hi guys ,

here is the second chapter regarding the drive of your robo car.

i made a mistake last post..not a mistake actually i could not put it clearly that all DC motors are not geared motors . the one which involves reduction in speed due to gears is a geared motor. whereas the one which u see in black colour is a normal dc motor that does not involve gears.

Now beginning with second chapter

You can use any material for the body of your robo. It can be either wood, M.S plate. Aluminium, etc. depending upon the weight requirements

Generally the cars on our roads are rear wheel drive. But for the competitions this won’t serve the purpose.Let us see the disadvantages
In the fig the one with dark rear wheel is rear wheel drive while the other is four wheel drive.{ ie. All the four wheels powered by motors }
How do the robo car overcome an obstacle ?
When a car is moving the wheel rotates in clockwise direction while moving forward. and hence the friction force acts in anticlockwise direction. This makes the car move forward.
Similarly it overcomes an obstacle.

Now if the car is climbing an inclined plane. Then in case of rear wheel drive there will be no friction force on the front wheels because they r not powered and hence unable to generate a reaction.
Due to this the car will topple upside down.

Same is the case while clearing an obstacle in rear wheel drive and it won’t be able to clear it.

But in four wheel drive each wheel generates a reaction . and there acts a friction force. Hence it is able to clear all the obstacles as well as climb the inclination with higher degree than that of rear wheel drive car.

The very fact that Centre of gravity plays an important role .

The C.G ON A FOR WHEEL DRIVE ACTS ON THE CENTRE OF THE BODY.

ON REAR WHEEL DRIVE IT ACTS BETWEEN THE TWO MOTORS.

by adding some dead weight on the front side and shifting the C.G somewhere in between can serve the purpose in rear wheel drive.

The very common example can be a normal four wheeler and a HUMMER.
Hummer is a four wheel drive vehicle hence can even climb uneven terrains..
we can also use a belt as used in tanks on wheels as it can be seen in the pic. above. but again this har advantage on the sand. what is observed during robotics competitions is that the belt comes off while overcoming an obstacle or by excessive jerks. hence it is advisable to avoid such method.
For normal competitions in robotics we need to clear a track in minimum possible time or win a knockout race. So we need speed as well as enough torque to overcome all obstacles. As I wrote on my last post a 300 r.p.m motor would serve both purpose and also it should be a four wheel drive.

BEGINNER TO ROBOTICS- I

2006-11-16T12:06:00.000+05:30

Hi Guys,

This particular post is for the beginners in robotics as few of my friends asked me to do so.

here we go with the first lesson on DC Motors.

DC motors are geared motors. These contain a Gear box at the top and the silver coloured part in the picture is the main motor that drives the axle.
as u can see in the first fig. to the extreme left . there are various gears in it. these are step gears which reduce the high r.p.m to the desired r.p.m
The main motor gives around 2000 r.p.m whereas the gear box reduces it to the desired r.p.m { 15 r.p.m in this case }

Now, one thing to keep in mind that the Torque is inversly proportional to the speed.

TORQUE = k/ SPEED

where k is a constant.

In a laymans language Torque is the power given by the motor to overcome the obstacle.
If you want high speed then u have to compromise with the Torque and if u want high torque than compromise with the speed.

Generally for normal robotics competition {level 1} one should go for 300 r.p.m motors as they provide you the combination of torque as well as speed.

I hope you guys got the concept of torque and speed by now..
chapter 2 will be coming soon......

GEAR BOXES

2006-11-14T20:06:00.000+05:30

Hi Friends

last time i posted about gears. now lets understand what are gear boxes.

Lets take an example { fig 3 the lower fig. }

The torque produced by the car's engine is not applied to the road directly; first, it is passed through a set of gears in order to optimise the engine speed for the road speed. The effect of the gearing is to change the number of times the engine rotates for each rotation of the road wheel. In addition to the gearbox itself, the differential (or `final drive') may alter the gear ratio as well as dividing the torque between the two front wheels.

Now there gear boxes can be of various types according to their need at a particular place.

1. RIGHT ANGLE WORM GEAR BOX {FIG 1}

{ extreme left fig on top}

The AGNEE Worm Gear Boxes have Cast Iron Gear Case of streamlined design completely air tight, dust proof and capable of being installed in open without any cover. The Worm Shaft is made of Alloy Steel, duly hardened and tempered. The Worm Wheel is made of Chill Cast Phosphorous Bronze and teeth accurately Generated on Gear Hobbing Machines. They are supported on Extra Heavy Duty Taper Roller anti friction Bearings of ample margin of safety to allow adequate journals as well as thrust loads. Lubrication is effected by splash of oil from the sump. Thus, no special care is required except for occasional oil topping to the required level. Air cooling is effected by means of standard polypropylene or metal fans.

2.HELICAL GEAR BOX {FIG .3}
{extreme right fig. on top}

Helical gear boxes are spiral gear boxes used in applications involving high shock loads. Helical gear boxes may require a larger initial investment, but maintain high efficiency.

LIGHT SENSOR

2006-11-13T13:42:00.000+05:30

hi guys,

just check out this light sensor circuit.

· Relay closes when no light falls on it.

For reversed action, exchange LDR1 and R1.

Sensitivity can be adjusted with P1.

D1 prevents sparking of relay coil.

TYPES OF GEARS

2006-11-12T14:56:00.000+05:30

RACK AND PINION [1st fig.]

A rack and pinion is a pair of gears which convert rotational motion into linear motion. The circular pinion engages teeth on a flat bar - the rack. Rotational motion applied to the pinion will cause the rack to move to the side, up to the limit of its travel.

BEVEL GEARS [2 nd fig.]

Bevel gears can be used to change the direction of drive in a gear system by 90 degrees. A good example is seen as the main mechanism for a hand drill. As the handle of the drill is turned in a vertical direction, the bevel gears change the rotation of the chuck to a horizontal rotation.

SPUR GEARS [ 3 rd fig.]

Spur gears are wheels with teeth that mesh together. Spur gears are used to change the speed and force of a rotating axle.

WORM GEAR [ 4th fig. ]

A worm gear, or worm wheel, is a type of gear that engages with a worm to greatly reduce rotational speed, or to allow higher torque to be transmitted. The image shows a section of a gear box with a bronze worm gear being driven by a worm. A worm gear is an example of a screw.

NEW PARALLEL PORT PROGRAMM

2006-11-11T13:59:00.000+05:30

#include
#include
#include
void main()
{
clrscr();
int i=50;
a:int k=getch();
switch (k)
{ //with out CAPSLOCK ON /////////

case 0:
goto a;
case 72:// up arrow
cout<<"\n up arrow";
outportb(0x378,0x06);
//front direction
goto a;
case 80:// down arrow
cout<<"\n down arrow";
outportb(0x378,0x09);
//back goto a;
case 75://
left arrow cout<<"\n left arrow"; outportb(0x378,0x0a);
//left goto a;
case 77:
// right arrow cout<<"\n right arrow";
outportb(0x378,0x05);//right
goto a;
case 32:// space bar cout<<"\n space bar";
outportb(0x378,0xff);//stop
goto a;
case 114:// r key for rise cout<<"\n r key for rise";
outportb(0x378,0x2f);//rise direction
goto a;
case 102:// f key for fall cout<<"\n f key for fall";
outportb(0x378,0x1f);//fall direction
goto a; //with CAPSLOCK ON for pulse motion//
case 82:// pulse for lifting cout<<"\n R key for pulse rise";
outportb(0x378,0x2f);//rise direction delay(i);
outportb(0x378,0xff);//stop direction
goto a;
case 70:// pulse for fall cout<<"\n F key for pulse fall";
outportb(0x378,0x1f);//fall direction
delay(i);
outportb(0x378,0xff);//stop direction
goto a;
case 71:// home key cout<<"\n home key for pulse up direction";
outportb(0x378,0x06);//front direction
delay(i); outportb(0x378,0xff);//stop direction
goto a;

case 79:
//end key cout<<"\n end key for pulse down direction";
outportb(0x378,0x09);//back
delay(i);
outportb(0x378,0xff);//stop direction
goto a;
case 83://del key cout<<"\n del key for pulse left direction";
outportb(0x378,0x0a);//left
delay(i);
outportb(0x378,0xff);//stop
goto a;
case 81:// page down cout<<"\n Pg down key for pulse right direction";
outportb(0x378,0x05);//right
delay(i);
outportb(0x378,0xff);//stop
goto a;
case 115:
// s key for stop cout<<"\n S key for stop";
outportb(0x378,0xff);
goto a;
case 27:
// ESC key cout<<"\n ESC"; break;default:
outportb(0x378,0xff);//stop direction
goto a;
};
//end of switch casecout<<"\n end of program";
outportb(0x378,0x00);
getch();
}//end of void mian

BLACK BIRD

2006-11-10T17:38:00.000+05:30

hi guys,check this out

this is the former US military plane named BLACK BIRD

THIS is a supersonic aircraft but now its history. The use of this marvellous aircraft was stopped since its missions were too expensive.

Can u believe this was targeted by various missiles ( around 2500 times) but this aircraft used to fly at such speeds that it would leave missile far behind.
interesting,isn't it ?

The camera that it used for spying was so sharp that it could also read number plates of the cars.

THis plane used to leave enemy airspace before the enemy cold realise that someone was on a recon. mission.
wow what a plane!!!!!!!!!!

SOLAR AIRCRAFT

2006-11-09T18:22:00.000+05:30

Hey guys check this out

NASA's Solar powered Aeroplane.
Isn't it cool

MINI PC's

2006-11-07T17:51:00.000+05:30

Hey look at this wonderful thing

seems like a pen .... right ?

yaaaaa u guessed it right this is a mini PC

have a look

hi guys

2006-11-06T20:48:00.000+05:30

my first posting at this blog.

thanks to bhargav
please let me know if it needs any upgradation at any point of time.