Start and Stop Symbologies
Barcode symbols have 'start' and 'stop' characters at the beginning and ending.These characters enable barcode scanners read bidirectionally, decoding the data in the correct order. Bar codes sometimes have 'check digit' at the end which is determined according to an algorithm based on the preceding characters.
Quiet Zones
1/4" wide area next to the start and stop characters having no markings is called quiet zones. If the area is too short, the bar code symbol will not be read by scanner.
Interpretation Line
This is a line of human-readable characters which is located beneath the bar code.
Bar/Space Patterns
These are wide and narrow black bars and whites spaces present in the bar code.
Inter-Character Gap
In some bar codes,each character is printed independently of other characters and is not part of the encoded character.Therefore it is separated by an inter-character gap.
Code Density
Code density is number of data/message characters which can be represented per unit length of space. Four variables affect code density and are as follows:-
All bar codes have different structures. Some are able to encode more information per inch than others
Ratio is important in deciding the type of scanning device to read the code. Changing the code density of a particular bar code is done by varying the ratio.
The width of the narrowest bar or space is referred to as the X dimension, usually given in mils. The X dimension dictates the width of all other bars and spaces, and ultimately the length of the bar code..
A laser, a spinning mirror (spins very fast), a receiver (for reflected laser light from the barcode), and a microprocessor (to send the number to a computer).
Americium is not used in bar code scanners.
The use of bar code scanners exploded in the 70s as the technology quickly spread to retail outlets.
"Bar Code scanners are available to the public. In fact, a bar code scanner application is standard fare on smart phones or phones with a camera and internet connection, and often come pre-installed."
invented in 1952
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Bar code scanners can definitely be bought online. Some websites specialize in selling these scanners. They cost anywhere from 40 dollars to over 600 dollars.
You can try DKData, they have Barcoding Equipment, Handheld Scanners, even RFIDs
There are handheld bar code scanners, so a handheld bar code scanner is a bar code scanner, but a bar code scanner is not necessarily a handheld scanner. There are bar code scanners in store checkout stands that are fixed, and there may or may not be an associated handheld scanner there for the clerk to use to scan, say, a large bag of dog food that the customer doesn't want to hoist up onto the counter.
Different bar code readers can be installed using Google's Play Store. The store offers a wide range of bar code scanners such as "Bar code Scanner from ZXing Team or Google's own implementation of a qr/bar code reader : Google Goggles.
Most bar codes you will see on consumer products have the numbers below. A Bar code is a way of making information readable to a machine. It does this, similar to morse code, by encoding normal letters and numbers as patterns of thick and thin black lines. The purpose of the bar code is to tightly control the comparison between the thick and thin lines, and the space in between, so that the pattern has a high chance of being read correctly. Every letter in the alphabet has a corresponding bar code character, when the bar code reader scans the bar code its electronics translate the bar code into the letters, and send these letters in machine code to the computer. Some bar code readers use what is called a "wedge" - they are plugged in between the keyboard and the computer, and send signals into the keyboard port of the computer exactly as if the operator had typed in the numbers on the bar code.
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Most bar code scanners will give you the price of an item , but if you are shopping and find one that does not , the price will come up at the checkout when you plug the scanner in .