Barcoding

The two dominant technologies is use today for barcode scanning are laser scanners and imagers.

Laser scanners use a laser diode, reflected off of a spinning mirror to “throw” the scanning beam out across the barcode. The sensor in the laser scanner decodes the reflected light coming back off of the white spaces in between the black bars on the barcode, converting this data into usable information.

An imager works in a similar way, but instead uses LEDs to illuminate the barcode, and a CCD sensor to capture the reflected light.  One major difference with imagers is that they are all solid state, so there is no electric motor turning a spinning mirror. Therefore, imagers tend to be less power hungry, which can be an advantage when using a battery-powered device.

On the other hand, when you need to scan a long distance  (e.g. more than say 700 mm for an average sized and reso

lution barcode) then you most likely will need to use a laser scanner.

Symbologies
Think of barcode symbologies as foreign languages; there are a bunch of them in use and they all have different attributes, limitations and capabilities. They have evolved out of different industries and “schools of thought”, and in many cases are specifically designed for a particular purpose. For example, EAN 13 is the industry standard barcode symbology in use for retail applications. Any retail item such as a bag of cookies or a box of blank CD ROMS will have an EAN 13 barcode on it.

Some of the symbologies, such as Code 128, are perfect for all around usage, and we recommend the use of this symbology for most “in house” applications where standardisation with others outside of your organisation is not required. For example, asset tracking.

There are one dimensional barcodes (1D) and two dimensional barcodes (2D)

1D Barcodes  
One dimensional barcodes  represent data in the widths (l

ines) and the spacings of parallel lines. 1D barcodes are the most prevalent and are the most widely used form of barcode. However, 1D barcodes are limited by the fact that the more data you wish to encode into the  barcode, the “longer” the printed barcode becomes, until you reach a point where it is impractical or impossible to read, or for that matter to print the barcode.   That is when 2D barcodes step in.

2D Barcodes

These come in patterns of squares, dots, hexagons and other geometric patterns within images termed 2D (2 dimensional) matrix codes or symbologies. 2D “matrix”  barcodes, such as the Denso QR codes contains data in both horizontal and vertical

directions, whereas other 2D barcodes such as PDF 417 utilise a “stacked bar” system.

The advantage of 2D barcodes over 1D is that a considerably larger  amount of data can be encoded into them (when com

pared to 1D) while taking up much less space per character of encoded data. For example, a 22 x 22 mm 2D QR code can contain 300 characters !

Further, matrix type 2D barcodes are omni-directional, so they can be read from any orientation/direction and be decoded successfully, even upside down.  QR code in particular also has considerable built-in redundancy such that you can practically destroy half of the barcode and still be able to read it.

We can supply handheld terminals with 1D laser, 1D linear imager, 1D long range laser, 1D autorange laser, and 2D imagers.

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