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How a Barcode Reader Works

Whether we like it or not the bar code scanner has become ingrained into our societies, and our daily lives. Practically every product that you buy from the store has a corresponding barcode. Think about it. When you go to the grocery, department store, shoe shop, pet store, sporting goods shop, hardware store, vending machine, convenience store, or practically any other shop out there, most [if not all] of these establishments make use of the barcode system in some shape or form. This is because the barcode system has become a universal tool for; logging, monitoring, and executing purchases and trades of all kinds. In this article, we’re going to learn more about the different kinds of barcode readers and how they work.

CCD Barcode Reader

Basically, this type of reader works by measuring the ambient light emitted by the barcode. Also known as a charge coupled device reader, the CCD scanner makes use of hundreds of micro light sensors. Arranged in a row, these sensors are placed at the head of the scanner. To further understand how this type of scanner works, think of each sensor as an individual photo diode that measures how intense the light is that is in front of it. Because each sensor is small enough, hundreds of it are placed in a row in order to generate a voltage pattern that is exactly similar to a barcode pattern. The voltages emitted across each light sensor are then sequentially measured.

Pen Reader

To read a barcode using a pen scanner, you have to move the pen across the barcode, scanning all of the bars in a steady motion. Because a pen scanner is composed of a photo diode and a light source placed next to each other at the
tip of the wand or pen-type reader, the photo diode measures the light intensity emitted back by the light source. This produces a waveform that measures the widths in-between dark bars and white spaces in the barcode. The scanner then
decodes this information by using a system that’s similar to how dashes and dots are decoded through Morse code.

Laser Scanner

The laser scanner works just like the pen reader, except that this time, the light source used is laser. Both pen and laser scanners also use a technology wherein the light emitted by the scanner is tuned to a certain frequency level, with the photo diode created to specifically detect this exact frequency.

Camera-Based Scanner

As one of the latest types of barcode readers, the camera-based scanner works by using a video camera to capture a barcode image. The scanner will then decode the information by using a sophisticated digital image processing method. The video camera uses a technology that’s similar to what a CCD reader uses, except that a video camera uses hundreds of rows filled with sensors. These hundreds of rows are then placed in a 2-D arrangement to generate a clear image.

All barcode readers are available with two kinds of output, which is either an RS232 or a keyboard wedge. A barcode reader with a keyboard wedge will require you to plug it directly into the keyboard. As for the RS232, you would need to
plug it into a serial port found at the back of your computer. To extract the data, you also need a special software.

If you’re looking for replacement bar code scanner batteries or a spare bar code scanner battery you should buy them from a reputable online merchant who sells bar code scanner batteries which are fully compatible with the manufacturers’ own brand replacements. LaptopsForLess.com has a huge selection of bar code scanner batteries in stock, at very reasonable prices [often a fraction of the cost of manufacturers’ own brand replacements]. Brands stocked include: Zebra, Intermec, PSC, Monarch, Symbol and more…