Working of barcode reader Ppt - Unitedworld School of Business
Working of Barcode Reader
What is Barcode?? Barcodes are simply a set of symbols used to representalpha-numeric information instead of seeing a number“1”, or letter “A”, you would see a series of black andwhite bars in various combinations and in different widths. These are used to encode data. The data encoded in suchbars can be decoded again to represent it in human readableform.
What is Barcode Reader?? A barcode reader (or barcode scanner) is an electronicdevice for reading printed barcodes. Like a flatbed scanner, it consists of a light source, a lensand a light sensor translating optical impulses into electricalones. Additionally, nearly all barcode readers contain decodercircuitry analyzing the barcodes image data provided bythe sensor and sending the barcodes content to thescanners output port.
Brief History As far back as the 1960s, barcodes were used in industrialwork environments. Some of the early implementations ofbarcodes included the ability identify rail road cars. In the early 1970s, common barcodes started appearing ongrocery shelves. To automate the process of identifyinggrocery items, UPC barcodes were placed on products. Today, barcodes are just about everywhere and are used foridentification in almost all types of business.
Working: A bar code consists of a series of parallel, adjacent barsand spaces. Symbologies are used to encode small stringsof character data into a printed symbol. A bar code reader decodes a bar code by scanning a lightsource across the bar code and measuring the intensity oflight reflected back by the white spaces. The pattern ofreflected light is detected with a photodiode whichproduces an electronic signal that exactly matches theprinted bar code pattern. This signal is then decoded backto the original data by electronic circuit.
Pen type readers and Laser Scanners Pen type readers consist of a light source and a photo diode thatare 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 barsin a steady even motion. The photo diode measures the intensityof the light reflected back from the light source and generates awaveform that is used to measure the widths of the bars andspaces in the bar code. Dark bars in the bar code absorb light and white spaces reflectlight so that the voltage waveform generated by the photo diodeis an exact duplicate of the bar and space pattern in the bar code.This waveform is decoded by the scanner in a manner similar tothe way Morse code dots and dashes are decoded.
CCD Readers CCD (Charge Coupled Device) readers use an array ofhundreds of tiny light sensors lined up in a row in the headof the reader. Each sensor can be thought of as a singlephoto diode that measures the intensity of the lightimmediately in front of it. Each individual light sensor in the CCD reader is extremelysmall and because there are hundreds of sensors lined up ina row, a voltage pattern identical to the pattern in a bar codeis generated in the reader by sequentially measuring thevoltages across each sensor in the row.
Camera based Readers The newest type of bar code reader currently available arecamera-based readers that use a small video camera tocapture an image of a bar code. The reader then usessophisticated digital image processing techniques to decodethe bar code. Video cameras use the same CCD technology as in a CCDbar code reader except that instead of having a single rowof sensors, a video camera has hundreds of rows of sensorsarranged in a two dimensional array so that they cangenerate an image.
Interfacing Bar code readers are available with two types of output -either "keyboard wedge" output or RS232 output.The bar code readers with keyboard wedge output plugdirectly into the keyboard port on your PC .The other option is RS232.With this type of bar code readerwe can connect available serial port on the back of PC.
Why use Barcodes?? When barcodes are used in the businessprocess, procedures are automated to increase productivityand reduce human error. Whenever there is a need to accurately identify or tracksomething, bar-coding should be used. For example, in adata entry work environment, workers may be required toenter an enormous amount of data into a customer databasesystem. Instead of manually typing a customer identificationnumber into a database, if the information is contained in abarcode, a data entry operator may scan it in. This wouldincrease automation and reduce human error.
Barcode types and use:The type of barcode to use for a particular situationdepends upon: The use. The data encoded in the barcode. How the barcode will be printed.There are several different types of barcode standardsfor different purposes - these are called symbologies.Each type of symbology (or barcode type) is astandard that defines the printed symbol and how adevice, such as a barcode scanner, reads and decodesthe printed symbol.
Contd.. When multiple parties or companies are involved in the IDprocess, industry standards are usually established. Notethat the standard is not necessarily the same as the barcodesymbology. If an industry standard has been established forthe customers use of bar-coding, then most likely there willnot be a choice in selecting the barcode symbology. Barcode standards define how to use the barcodesymbology in a particular situation. For example, ISBN is astandard for labeling books and periodicals that uses theEAN-13 symbology.
Two types of Barcodes(examples):Linear Barcodes 2D BarcodesCode 128 Data MatrixUPC Pdf 417
Some Established Barcode IndustryStandards:Established standard Common use SymbologyAIAG Automotive itemidentificationData MatrixUPCA, EAN13 Items for saleworldwideUPC/EANMIL-STD-130L US Department ofdefenseData MatrixSSCC-18 Shipping cartons Code 128
Benefits of Barcoding: ACCURACY OF DATA INPUT (ERROR FREE) AID EFFECTIVE MANAGEMENT OF RESOURCES AND INVENTORIES LABOUR SAVINGS BY AVOIDING MANUAL SYSTEM COST EFFICIENT REAL TIME DATA COLLECTION MEASUREMENT OF WORK IN PROGRESS THROUGHOUT THEFACTORY RAPID ACCESS TO TOTAL PRODUCTION COSTS MORE ACCURATE DISPATCH
Applications: RETAIL APPLICATIONS Super markets Counter-mounted Bar Code scanners Universal Product Code (UPC) Price and description information WARE HOUSING HEALTH CARE APPLICATIONS Drugs, devices, instruments Identification of expiry date Blood banking• Blood group• Expiry date• Donor traceability