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How do Bar code Scanners work? To understand how a barcode scanner works, we have to explore the different parts of the device. Basically, there are 3 functional parts to the bar code scanner itself, the illumination system, the sensor / converter, and the decoder. The simple explanation... Barcode scanners begin by illuminating the code with red light. The sensor of the barcode scanner detects the reflected light from the illumination system and generates an analog signal with varying voltage that represent the intensity (or lack of intensity) of the reflection. Theconverter changes the analog signal to a digital signal which is fed to the decoder. Thedecoder interprets the digital signal, does that math required to confirm and validate that the barcode is decipherable, converts it into ASCII text, formats the text and sends it to the computer the scanner is attached to. Let's look at each functional part of a barcode scanner in more detail: Illumination Systems - The illumination system is the method by which the bars and spaces on the barcode are illuminated. There are a variety of illumination systems commonly used in barcode scanners:
Pen Type Readers and Laser ScannersPen type readers consist of a light source and a photo diode that are placed next to each other in the tip of a pen or wand. To read a bar code, you drag the tip of the pen across all the bars in a steady even motion. The photo diode measures the intensity of the light reflected back from the light source and generates a waveform that is used to measure the widths of the bars and spaces in the bar code. Dark bars in the bar code absorb light and white spaces reflect light so that the voltage waveform generated by the photo diode is an exact duplicate of the bar and space pattern in the bar code. This waveform is decoded by the scanner in a manner similar to the way Morse code dots and dashes are decoded. Pen type readers and laser scanners can be purchased with different resolutions to enable them to read bar codes of different sizes. The scanner resolution is measured by the size of the dot of light emitted by the reader. The dot of light should be equal to or slightly smaller than the narrowest element width ("X" dimension). If the dot is wider than the width of the narrowest bar or space, then the dot will overlap two or more bars at a time thereby causing the scanner to not be able to distinguish clear transitions between bars and spaces. If the dot is too small, then any spots or voids in the bars can be misinterpreted as light areas also making a bar code unreadable. The most commonly used X dimension is 13 mils (roughly 4 printer dots on a 300 DPI printer). Because this X dimension is so small, it is extremely important that the bar code is created with a program that creates high resolution graphics (like B-Coder).  Laser scanners work the same way as pen type readers except that they use a laser beam as the light source and typically employ either a reciprocating mirror or a rotating prism to scan the laser beam back and forth across the bar code. Just the same as with the pen type reader, a photo diode is used to measure the intensity of the light reflected back from the bar code. In both pen readers and laser scanners, the light emitted by the reader is tuned to a specific frequency and the photo diode is designed to detect only this same frequency light. |
Showing posts with label Miscellaneous. Show all posts
Showing posts with label Miscellaneous. Show all posts
How Touch Screen Technology Works
This is for every person who ever wondered how in the world the iPhones touch screen works!! Ill add more to how the GUI works and about the iPhone for all the noobs like me who had no idea how it works. until now...
The basic idea is pretty simple -- when you place your finger or a stylus on the screen, it changes the state that the device is monitoring. In screens that rely on sound or light waves, your finger physically blocks or reflects some of the waves. Capacitive touch-screens use a layer of capacitive material to hold an electrical charge; touching the screen changes the amount of charge at a specific point of contact. In resistive screens, the pressure from your finger causes conductive and resistive layers of circuitry to touch each other, changing the circuits' resistance.
Most of the time, these systems are good at detecting the location of exactly one touch. If you try to touch the screen in several places at once, the results can be erratic. Some screens simply disregard all touches after the first one. Others can detect simultaneous touches, but their software can't calculate the location of each one accurately. There are several reasons for this, including:
Many systems detect changes along an axis or in a specific direction instead of at each point on the screen.
Some screens rely on system-wide averages to determine touch locations.
Some systems take measurements by first establishing a baseline. When you touch the screen, you create a new baseline. Adding another touch causes the system to take a measurement using the wrong baseline as a starting point.
Multi-touch Systems
To allow people to use touch commands that require multiple fingers, the iPhone uses a new arrangement of existing technology. Its touch-sensitive screen includes a layer of capacitive material, just like many other touch-screens. However, the iPhone's capacitors are arranged according to a coordinate system. Its circuitry can sense changes at each point along the grid. In other words, every point on the grid generates its own signal when touched and relays that signal to the iPhone's processor. This allows the phone to determine the location and movement of simultaneous touches in multiple locations. Because of its reliance on this capacitive material, the iPhone works only if you touch it with your fingertip -- it won't work if you use a stylus or wear non-conductive gloves.
Interpreting Touch-location Data
The iPhone's processor and software are central to correctly interpreting input from the touch-screen. The capacitive material sends raw touch-location data to the iPhone's processor. The processor uses software located in the iPhone's memory to interpret the raw data as commands and gestures. Here's what happens:
Signals travel from the touch screen to the processor as electrical impulses.
The processor uses software to analyze the data and determine the features of each touch. This includes size, shape and location of the affected area on the screen. If necessary, the processor arranges touches with similar features into groups. If you move your finger, the processor calculates the difference between the starting point and ending point of your touch.
The processor uses its gesture-interpretation software to determine which gesture you made. It combines your physical movement with information about which application you were using and what the application was doing when you touched the screen.
The processor relays your instructions to the program in use. If necessary, it also sends commands to the iPhone's screen and other hardware. If the raw data doesn't match any applicable gestures or commands, the iPhone disregards it as an extraneous touch.
All these steps happen in an instant -- you see changes in the screen based on your input almost instantly. This process allows you to access and use all of the iPhone's applications with your fingers. We'll look at these programs and the iPhone's other features in more detail in the next section, as well as how the iPhone's cost measures up to its abilities.
The Davy Safety Lamp
 | When metal gauze is inserted between a flame and a combustible gas, the heat of the flame is absorbed and driven away, preventing the gas from exploding. This controlled burn is the basic principle of Cornish chemist Sir Humphry Davy's safety lamp, replacing miner's candle stubs worn on their rosin-hardened, felt helmets. |
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World's first prosthetic limb
World's first prosthetic limb found on 3,000-year-old Egyptian mummy
The false toe worn by a 3,000-year-old mummy has always been regarded as a simple ornament, added after death as part of burial rites.
But British scientists who have studied it believe the reality is that it is the world's first working artificial body part, centuries older than anything previously found.
A false toe made of out of wood and leather was found on a 3,000-year-old mummified body of an Egyptian noblewoman
Now they are looking for volunteers who are missing the big toe on their right foot to wear a replica and try out their theory.
The original prosthetic, made out of wood and leather, is strapped to the foot of the mummified body of an Egyptian noblewoman currently on display at a museum in Cairo.
A similar false toe is worn by another mummy at the British Museum, but it has always been thought they were fitted after death as part of burial rites, perhaps to help them get about in the afterlife.
But a British Egyptologist who has examined both believes they were actually expertly fashioned to help their wearers get about and overcome their missing digit while they were still alive.
Both show what she believes are signs of wear and tear, and the Cairo toe is also jointed in the same way as a real one.
The appendage can bend in three places - just like a real toe - and scientists are now certain that it is a prosthetic
Now the team from Manchester University are to produce replicas which will be worn by volunteers to help them establish whether their theory is correct.
If true, the Cairo toe will be the world's oldest artificial body part, beating a leg forged from bronze by the Romans in around 300BC.
"We will use state-of-the-art technology to test whether the replicas of the artificial toes benefit the wearer and could therefore be deemed functional," said researcher Jacky Finch.
"The toes date from between 600 and 1,000BC, so if we can prove that one or both were functional then we will have pushed back prosthetic medicine by as much as 700 years."
The Cairo toe is articulated, just like the real thing, and is attached by a leather strap to the right foot of the woman, aged between 50 and 60. Her big toe had been amputated, and examination of her mummified body shows the site to have healed well.
The team has also examined a second false big toe found in an Egyptian sarcophagus and now held at the British Museum.
Known as the Greville Chester Great Toe, it is made from a papier mache-like substance and also shows signs of wear-and-tear, but it does not bend and is thought to have been a cosmetic replacement.
Now the researchers plan to recreate the articulated false toe and are looking for volunteers whose right foot is missing a big toe to trial it.
They will be examined under laboratory conditions to establish whether the device works well enough to have served as an artificial toe aiding walking and balance as much as 3,000 years ago.
The oldest known functional prosthesis was the Roman Capua Leg, made out of bronze and dating from about 300BC.
It was held at the Royal College of Surgeons in London but was destroyed by Luftwaffe bombs during the Second World War.
World's First electric car
The world's first electric car... built by a British inventor in 1884
The world's first electric car may have been built by a Victorian inventor.
Newly unearthed photos show what appears to be an electric vehicle built in the year 1884.
To the modern eye the machine looks like a horseless carriage, but sitting aboard at the wheel is the 19th century inventor Thomas Parker.
Could this be the world's first electric car? Thomas Parker (C) was a Victorian inventor who claimed to have invented the vehicle
Mr Parker electrified the London Underground and created overhead tramways in Liverpool and Birmingham, and the smokeless fuel coalite.
He claimed he had invented the electric car and he also had a hand in refining car batteries for petrol-powered models. He died in December 1915.
Nuclear fusion
 | Nuclear fusion is the energy source of the future. It is what provides the sun and the stars with the energy to shine continuously for billions of years. Fusion has been used here on earth to produce nuclear bombs, but has not yet been controlled so that we can obtain useful energy. We will try to show how fusion works, and describe current efforts to tame this limitless energy source. |
The nuclei used by the sun, and in experiments on earth, that undergo fusion, are two isotopes of hydrogen called deuterium and tritium.
The first generation fusion reactors will use deuterium and tritium for fuel because they will fuse at a lower temperature. Deuterium can be easily extracted from seawater, where 1 in 6500 hydrogen atoms is deuterium. Tritium can be bred from lithium, which is abundant in the earth's crust. In the fusion reaction a deuterium and tritium atom combine together, or fuse, to form an atom of helium and an energetic neutron.
It only takes a small amount of these isotopes to produce a lot of energy! The deuterium-tritium fusion reaction results in an energy gain of about 450:1!! No other energy source we can tap releases so much energy for the amount that is input.
It only takes a small amount of these isotopes to produce a lot of energy! The deuterium-tritium fusion reaction results in an energy gain of about 450:1!! No other energy source we can tap releases so much energy for the amount that is input.
But there's a catch! In the sun, the energy to force nuclei together comes from the sun's immense internal temperatures, approaching 40,000,000 or more degrees at the center! In order to cause nuclei to fuse here on earth (and release their stored energy), they must either be heated to that temperature, or caused to move fast enough to simulate a correspondingly high temperature.
That has been done already, more than 50 years ago. The energy to set off the fusion reaction was supplied by an atomic bomb, and the fusion reaction that resulted was called a 'hydrogen bomb'! But the energy release was all at once, and uncontrollable. While scientists were easily able to control atomic explosions, to create reasonably safe nuclear energy in atomic power plants, no such controlled reaction has yet been achieved for fusion.
The reason lies in where the energy comes from.
Nuclear fission of a plutonium nucleus already happens naturally ... we just help it along by allowing the reaction to proceed faster.
Nuclear fusion, on the other hand, requires that the fuel nuclei be moving very fast, or be heated to very high temperatures. Scientists for the last 50 years have been trying to figure out how to do this, but so far the technology at our disposal is not equal to the task!
Here are two different ways that we might achieve 'controlled' fusion, that are currently being explored in laboratories around the world.
In November 1997, researchers exploiting the magnetic confinement approach created a fusion reaction that produced 65 percent as much energy as was fed into it to initiate the reaction. This milestone was achieved in England at the Joint European Torus, a tokamak facility--a doughnut-shaped vessel in which the plasma is magnetically confined. A commercial fusion reactor would have to produce far more energy than went into it to start or maintain the reaction.
A 'Tokamak' reactor. Powerful magnets keep the
charged nuclei moving in a circle, at high speeds.
'Tokamak' is a Russian acronym for 'toroidal magnetic chamber. This device was first developed by Russian scientists. A tokamak is a toroidal plasma confinement device, resembling a doughnut in shape. The plasma is confined not by the material walls but by magnetic fields. The reason for using magnetic confinement is twofold. First, no known material can withstand the hundred-million degree temperatures required for fusion. Second, keeping the plasma in a magnetic bottle insulates it well, making it easier to heat up.
(Such reactors are inherently safe. If the plasma escapes, it immediately cools down, and the reaction stops!)
Escaping neutrons and energy would heat a body of water; a steam turbine and generator would produce electricity.
This magnetic confinement method for producing fusion is regarded by some scientists as the most promising one for future commercial energy sites. This stems from the way Magnetic Confinement fusion works, which allows for a sustained reaction and thus continuous energy production. Many 'tokamaks' are in operation currently, around the world, and more are planned for the future. But so far, none have been able to sustain the reaction for more than a few seconds ... the plasma leaks out. Improved magnet design and higher input power will perhaps allow these reactors in the future to maintain a fusion reaction indefinitely, producing copious amounts of power ... from seawater!
Lasers can do this. After many years of research, scientists have plans to build a very powerful laser that will produce at least as much energy from fusion as the laser delivers to the pellet, ... but that will still not come close to producing the several 100-fold greater energy required to power the laser itself. That goal requires a fusion energy output much greater than the energy put into the laser. Present laser technology is too expensive to go further, for now.
A laser bombardment device.
Here's how it's supposed to work. Many pulsed laser beams hit the fuel pellet simultaneously, causing the surface of the pellet to become a very hot plasma.
This plasma expands inward, compressing the remaining deuterium and tritium so much that its temperature rises to the required 100,000,000 degrees. For about one tenth of a billionth of a second, there are the same conditions inside the pellet as those inside a star, ... and fusion takes place.
To generate 1000 MW of electricity using such a reactor would require microexplosions of about six pellets in one second. This takes into consideration the inefficiency of the conversion from heat to electrical energy.
In order to achieve these microexplosions, a chamber created to carry away the heat generated by the fusion would be built. A pellet would be shot into the center of the chamber and then the laser or particle accelerator would fire onto it, causing implosion and fusion. This would need to be repeated about six times a second.
This method would probably work, but because it is not self-sustaining, (you have to keep feeding in the pellets), it is not very efficient. Most researchers now believe that magnetic containment devices will be the first ones to actually sustain a fusion reaction.
Who are Best Frnnzzz!!
A best friend is always there,
whether you need advice,
or a pep talk,
or even a shoulder to cry on.
A best friend listens with heart
and is always honest with you,
even though the truth
may not be
what you want to hear.
A best friend
knows all your secrets,
understands your fears
shares your dreams.
A best friend never stops believing in you
even if you give upon yourself.
you are that kind of friendto me.
And no matter what happens,
you always will be.
You are my best friend....my forever friend.
whether you need advice,
or a pep talk,
or even a shoulder to cry on.
A best friend listens with heart
and is always honest with you,
even though the truth
may not be
what you want to hear.
A best friend
knows all your secrets,
understands your fears
shares your dreams.
A best friend never stops believing in you
even if you give upon yourself.
you are that kind of friendto me.
And no matter what happens,
you always will be.
You are my best friend....my forever friend.
Jokes
Classic Jokes
- A man walks into a hamburger shop and orders a regular meal. Later, the waitress brings his meal to him. He takes a bite out of it, and notices there's a small hair in the hamburger. He begins yelling frantically at the waitress, "Waitress, there's a hair in my hamburger! I demand to see what is going on!"
- So, the waitress takes him back where the cook is and to his demise, he sees the cook take the meat patty and flatten it under his arm pit. He says, "That's disgusting!"
- Then the waitress says, "You think that's disgusting you should see him make donuts."
- One day an Indian boy asked his father why they have such long names? The dad answers, "Well son whenever a Indian baby is born the father would go outside and name the baby after the first thing he sees... Why do you ask Two Dogs Fucking."
- There were these three guys. They had been walking for 3 days and were very tired. They found a hotel, rented a room and went to sleep. Then, this old guy comes in out of nowhere, and says there is a magic pool just outside their hotel room. He tells them "Ok, you must jump off the diving board, and yell out what you wanna land in."
- So the three guys go over to the pool. The first guy, a vegetarian, yells out "Bananas!" and lands in a pool of bananas. The second guy was money hungry and yelled out "Money!" and lands in a pile of money. The third guy jumps, when a bird shits on his head, and he yells "Oh Shit!"
- A young blind boy is being tucked into bed by his mother. The mom says "Now Billy, pray really hard tonight and tomorrow, your wish will come true!". Billy says, "Ok mommy." and goes to sleep. The next morning, Billy wakes up and screams "MOMMY! I'm still blind, my wish didn't come true!", the mom answered, "I know - April Fools!"
- A woman was standing in a crowded lift of the hotel she was staying in. When a man got in and accidentally elbowed her in the breast. The man said, "I'm sorry! But if your heart is as soft as your tit, you'll forgive me." so the woman replies, "If you dick is as hard as your elbow then I am staying in room 113."
- A few days after Christmas, A mother was working in the kitchen listening to her son playing with his new electric train set in the living room. She heard the train stop and her son yell "All you sons of bitches who want to get off, get the hell off now, because this is the last stop! All of you sons of bitches that are getting on, get your asses in the train cause were leaving". The mother went in and told her son, "we don't use that kind of language in this house." Now I want you to go into your room for two hours. When you come out, you can play with your train, but I don't want to hear any bad language.
- Two hours later, the son comes out of his room and continues playing with his train. Soon the train stopped and the mother heard the son say, "All passengers who are disembarking the train, please remember to take all of your belongings with you. We thank you for riding with us today and hope your ride was a pleasant one. We hope you will ride with us again soon. For those of you who are just boarding the train, we ask that you stow all of your hand luggage under the seat, remember there is no smoking except on the club car. We hope you have a pleasant and relaxing journey with us today".
- "For those of you who are pissed off with the two hour delay , please see the bitch in the kitchen."
- A young couple gets married, and the groom asks his bride if he can have a dresser drawer of his own that she will never open. The bride agrees. After 30 years of marriage, she notices that his drawer has been left open. She peeks inside and sees 3 golf balls and $1,000.
- She confronts her husband and asks for an explanation. He explains "Every time I was unfaithful to you, I put a golf ball in the drawer." She figures 3 times in 30 years isn't bad and asks "But what about the $1,000?" He replied "Whenever I got a dozen golf balls, I sold them"
- A mother found her son scooping ice cream in the kitchen and was mad.
- Mom : "Dinner is going to be ready in an hour, put that ice cream away and go play."
- Son : "But mom, there's no one to play with."
- Mom : "I'll play with you, what do you wanna play?"
- Son : "Lets play mommy and daddy, you go upstairs and lay down on the bed."
- The mom said ok and went upstairs. The son put on his dad's fishing hat and lit up one of his dad's cigarettes. He went upstairs and opened the door.
- Mom : "Now what do I do?"
- Son : "Get your ass out of bed, you whore, and fix that kid some fucking ice cream."
- An 80 year old couple were having problems remembering things, so they decided to go to their doctor to get checked out to make sure nothing was wrong with them.
- When they arrived at the doctors, they explained to the doctor about the problems they were having with their memory. After checking the couple out, the doctor told them that they were physically okay but might want to start writing things down and make notes to help them remember things.
- The couple thanked the doctor and left. Later that night while watching TV, the man got up from his chair and his wife asked, "Where are you going?" He replied, "To the kitchen." She asked, "Will you get me a bowl of ice cream?" He replied, "Sure." She then asked him, "Don't you think you should write it down so you can remember it?" He said, "No, I can remember that."
- She then said, "Well I would also like some strawberries on top. You had better write that down because I know you'll forget that." He said, "I can remember that, you want a bowl of ice cream with strawberries." She replied, "Well I also would like whipped cream on top. I know you will forget that so you better write it down."
- With irritation in his voice, he said, "I don't need to write that down! I can remember that." He then fumes into the kitchen. After about 20 minutes he returned from the kitchen and handed her a plate of bacon and eggs. She stared at the plate for a moment and said angrily: "I TOLD you to write it down! You forgot my toast!"
- One day a girl brings home her boyfriend and tells her father she wants to marry him. After talking to him for while, he tells his daughter she can't do it because he's her half brother. The same problem happens again four more times! The girl starts to get pissed off. She goes to her mom and says, "Mom... What have you been doing all your life? Dad's been going around laying every maiden in the town and now I can't marry any of the five guys I like because they have turned out to be my half brothers!!!"
- Her mom replies, "Don't worry darling, you can marry any one of them you want, he isn't really your dad."
- The patient says, "Give me the bad news first!"
- Doctor replies, "You've got AIDS."
"Oh, no! What could be worse than that?" asks the patient.
"You've also got Alzheimer's Disease."
Looking relieved the patient says, "Oh...Well, that's not so bad. At least I don't have AIDS."
- Mr.Johnson and his secretary are on a train to Paris. They are just about to go to sleep when the secretary, who has the hots for her boss says in a seductive voice, I'm a little cold, could I borrow your blanket? The man says how would you like to be Mrs. Johnson for awhile? The secretary jumps at the chance and begins to get out of bed. Then he replies, good, then you can get your own damn blanket.
- A burglar breaks into a house. He sees a CD player that he wants so he takes it. Then he hears a voice "JESUS is watching you". He looks around with his flashlight wandering "What The HELL Was That?". He spots some $ on a table and takes it......Once again he hears a voice " JESUS is watching you". He hides in a corner trying to find where the voice came from. He spots a birdcage with a parrot in it! He goes over and asks " Was that your voice?". It said "YES". He then says "What's your name?". It says "MOSES". The burglar says " What kind of person names his bird moses??" The parrot replys "THE SAME PERSON THAT NAMES HIS ROTWEILER "JESUS".
- During their silver anniversary, a wife reminded her husband: Do you remember when you proposed to me, I was so overwhelmed that I didn't talk for an hour?" The hubby replied: "Yes, honey, that was the happiest hour of my life."
- A soldier was given the job of hunting for buffalo. To help him, he hired an Indian Scout. The two of them set off on their journey to find buffalo. After riding awhile, the Indian gets off his horse, puts his ear to the ground and says "Humm, buffalo come". The soldier scans the area with his binoculars, but sees nothing. He is confused and says to the Indian, "I do not see anything, how do you know buffalo come"? and the Indian replies, "ear sticky".
- A guy walks past a mental hospital and hears a moaning voice "13.......13.......13.........13" the man looked over to the hospital and saw a hole in the wall, he looked through the hole and gets poked in the eye. The moaning voice then groaned '14.........14.........14.......14.'
Celebrity Jokes
- Q. How can you tell if Michael Jackson has company?
- Q. What's the difference between Neil Armstrong and Michael Jackson?
- Q. How does Michael Jackson pick his nose?
- Q. Why did Michael Jackson place a phone call to Boyz-2-Men?
- Q. What has 18 balls and 3 pubic hairs?
- Q. Why does Hillary want to have sex with Bill Clinton first thing in the morning?
- Q. What's Bill Clinton's idea of safe sex?
- Q. Did you hear that Monica Lewinsky turned Republican?
- Q. How come Mike Tyson�s eye's water during sex?
- Q. What does Ellen DeGeneris cook for dinner every night?
- Q. Why can't the government put Magic Johnson on a stamp?
- Q. What's the difference between Christopher Reeves and OJ Simpson?
- Q. What's white and sticky and found on the bathroom wall?
- Q. What do you call a man with a blackhead on his dick?
- Q. What's the difference between George Michael and a microwave oven?
- Q. How does Michael Jackson know its time for bed?
A. When the big hand is on the little hand.
- Q. What's the difference between Michael Jackson and a plastic bag?
A. One is white, plastic and dangerous to young children, the other is a plastic bag.
- Q. How did Helen Keller's mother punish her?
- Q. What did Helen Keller do when she fell down the well?
- Q. Why does Helen Keller masturbate with one hand?
- Q. Why was Helen Keller's leg yellow?
- Q. What did Helen Keller's parents do to punish her for swearing?
- Q. Why did Bill Clinton stop playing the saxophone?
- Q. Do you know why Monica got a stain on her dress?
- Q. What does Wal-Mart, Zellers and Michael Jackson have in common?
- Q. 100 Women Surveyed, "Would you have sex with Bill Clinton?"
- Q. What's green and smells like Monica Lewinsky?
- Q. What does McDonald's and Michael Jackson have in common?
- Q. What does Bill Clinton and a country folk dancer have in common?
- Q. Why did Bill Clinton name his new dog Buddy?
********************* COMING SOON************************
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