How do bar codes work?

Answer 1

bar codes work by when the scanner scans the bar code, its looks through the numbers and recognises the item and the price. this is because when the product is made its bar code is made to recognise the item and it is put a price on. they use computer technology to do all of this.

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Basically its till scanners or laser readers consist of a light source and a photo diode that are placed next to each other in the scanner housing (or hand held scanner). To read a bar code, you pass the item across the scanner in a steady even motion. The photo diode measures the intensity of the light reflected back from the light source (the bar-code white and black lines) 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. It then interprets the wave form in to a numeric code.

i.e.

The last digit of the UPC code is called a check digit. This digit lets the scanner determine if it scanned the number correctly or not. Here is how the check digit is calculated for the other 11 digits, using the code 63938200039 from "The Answers.com world of wonder " (made up name )

Add together the value of all of the digits in odd positions (digits 1, 3, 5, 7, 9 and 11).

6 + 9 + 8 + 0 + 0 + 9 = 32

Multiply that number by 3.

32 * 3 = 96

Add together the value of all of the digits in even positions (digits 2, 4, 6, 8 and 10).

3 + 3 + 2 + 0 + 3 = 11

Add this sum to the value in step 2.

96 + 11 = 107

Take the number in Step 4. To create the check digit, determine the number that, when added to the number in step 4, is a multiple of 10.

107 + 3 = 110

The check digit is therefore 3.

Once the computer (the till or the computer the scanner is attached to) is satisfied that the check digit is right it searches for the code, 63938200039 in its database and when found returns the price, description etc . The same system is used for most products that carry a bar-code from retailers to warehousing to manufacturing to UPS sending parcels world wide.

In the case of a retailer the code, in this case 63938200039 starts life being punched in to the computer which drives the tills. The code is added and a description, price etc is attached to that number. In a retail outlet the company use their own internal code to start the process i.e. 1234 = 750ml bottle of pepsi (or any-other drink) attached to that internal code is the bar-code given to the retailer by the supplier. This is because a product carrying a bar-code can have different information attached by the manufacturer. as an example pepsi in our case on the shelf as a special offer attached to the label. The customer saves 5 labels and sends to the company and gets a free pepsi glass the bar code of a normal (no offer bottle ) may have 63938200039 as its code. The offer bottle will have to have a different bar code because technically there has been a change in some way to the "normal" product so the new code could be 63938200044. The manufacturer tells the retailer of the new code and in the till system now has item;

1234 - Pepsi 750ml bottle - 63938200039

1234 - Pepsi 750ml bottle - 63938200044

The database will now recognise either bar-code as Pepsi 750ml Bottle. This is why on occasion when you arrive at a till in a store they scan the barcode and the till cannot recognise it. The till operator calls for someone to check this - Then it is frequently found that a batch of products has not had its barcode number ntered to teh system.

Answer 2

A barcode reader works by directing a laser across the bar code and measuring the amount of light that is reflected back to its photosensors.

A scanner, imager or reader will act just like any other input device for your computer. When the cursor is in the field on any application or form that you will be using and an item is scanned, the data will enter the field exactly as if someone was typing the data into the field. There is no additional software that is needed to load for this to work. The only set up may be required would be to initialize the scanner by scanning the corresponding barcodes that are in the user manual.

In a store each barcode represents a certain item that is for sale. The scanner knows which barcode is which, so it can read the item for the price or other features of the item.

Answer 3

Bar codes were created to help grocery stores speed up the checkout process. UPC bar codes,which stand for 'Universal Product Code' were first used in grocery stores. Every store item needs a different code so that it can be scanned correctly. The last digit of a UPC bar code is called the check digit and is calculated by the other 11 digits. For example, if you were to find the check digit for the UPC code 63938200039...: 1.) Add together all the digits in odd positions (1,3,5,7,9,11) 6 + 9 + 8 + 0 + 0 + 9 = 32 2.) Multiply the number by 3 32 x 3 = 96 3.) Add together all the digits in even positions (2,4,6,8,10) 3 + 3 + 2 + 0 + 3 = 11 4.) Add the sum to the value in Step 2 96 + 11 = 107 5.) Take the answer 107. To create the check digit, determine the number that, when added to the number 107, is a multiple of 107 107 + 3 = 110 So, the check digit is 3. A Barcode is an optical machine-readable representation of data.

Answer 4

A barcode scanner works as a keyboard input device. Where ever your cursor is on your computer screen, the data that you are scanning will appear.