Light pen

Barcode reader

by Paakhi, Prarthna, Neha, Kannagi, Juveria – IX D

A barcode reader (or barcode scanner) is an electronic device for reading printed barcodes.

Like a flatbed scanner, it consists of a light source, a lens and a light sensor translating optical impulses into electrical ones.

Additionally, nearly all barcode readers contain decoder circuitry analyzing the barcode's image data provided by the sensor and sending the barcode's content to the scanner's output port.

What is a Barcode?A barcode is a pattern ofprinted bars on various types ofproducts.

How does the Barcode Reader work?A light-sensitive detector in thebarcode reader that identifiesthe bar code image byrecognizing special bars at theboth ends of the image.

Barcode readers can be differentiated by technologies as follows:________________________________________________________________

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Pen type readersLaser scannersCCD readersCamera based readersOmni-directional barcode

scannersPen scannersPDA scanners

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A light pen is a computer input device in theform of a light-sensitive wand used inconjunction with a computer’s CRT display.

It allows the user to point to displayedobjects or draw on the screen in a similar wayto a touch screen but with a greater positionalaccuracy . It was long though that a light pencan work with any

It was long though that a light pen can workwith any CRT-based display , but not withLCDs and other display technologies .However, in 2011 fairlight instrumentsreleased its fairlight CMI-30A , which uses17’’ LCD monitor with light pen control .

What is a light-pen?A handheld pen-likephotosensitive device held tothe display screen of acomputer terminal for passinginformation to the computer.

How does the light-penwork?A light pen detects a change ofbrightness of nearby screenpixels when scanned by cathoderay tube election beam andcommunicates the timing of theevent of the computer.