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Barcode Scanners and Readers

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What are they used for...?

Barcode scanners and barcode readers are used to quickly, easily and accurately capture information represented in a bar code, usually to link it to data in a computer database.

Reading Technology

There are several different approaches to reading barcodes. Some have advantages in a specific application. Others are being phased out, replaced by superior technology. Here is an outline.

CCD scanners, or "imagers"

Bar Code Readers

This is the preferred technology in most applications. It is built on the same technology as the camera used in a smartphone, and the volume of units produced for smartphones helps keep the prices lower for these barcode readers. In essence, the reader takes a picture, and analysis it subsequently.

All solid state, so no moving parts, which means greater reliability and better at surviving rough treatment. No need to align with the barcode to be read. Many are able to read 2D as well as 1D barcodes. They can also usually read a barcode from a screen, which is particularly useful in reading a barcode displayed on a smartphone. This capability has meant that many laser readers have been replaced over the last few years, especially in retail applications.

This is a big improvement over the early models, which were generally designed to read when held about half an inch from the bar code, which meant that they were less convenient to use than lasers in some applications.

Laser barcode scanners

Bar Code Readers

Important in the evolution of barcode readers, they were far better than the previous wand readers, needing less skill, and being able to read at range and through transparent covering. Although having moving parts meant that they were prone to failure on drop, later models used a flexible strip to achieve more rugged performance.

These readers could only read 1D barcodes, and needed to be aligned with the barcode, which could be a problem with very long barcodes. Now you shouldn't really have very long barcodes, but that is a different story.

Bar Code Wands

Bar Code Readers

Were at one time very popular for their exceptionally lightweight and lower cost. However, the drop in CCD prices makes cost less significant. Bar Code Wands are considered acceptable in environments such as libraries, where the barcode is on a flat, convenient work surface. In most other applications the wands have been replaced by lasers or CCDs.

Reading a barcode with a wand required a certain knack. The main requirement was a constant speed across the code. A common failing was to begin from a standing start at the beginning of the code, and come to a full stop at the end. Far better to start an inch or so to one side, and keep on swiping well past the end of the code.

Accuracy

In practice, this is not an issue, particularly with imagers. All readers can now read barcodes which are slightly damaged, or incorrectly printed such that they would fail to meet specification. Introduction of fuzzy logic and other techniques for analysing the captured image of the barcodes has become so good that barcodes that are partially covered in dirt, or damaged, can often be read.

1D or 2D barcodes

We address this elsewhere on the web site.  There is often an enthusiasm for 2D barcodes which is difficult to justify when carefully analysed. Very few applications truly need 2D. And bear in mind that opting for 2D barcodes means that you are restricting your choices for readers.

Long range or Standard Range

Readers can now interpret a barcoded label at ranges up to thirty feet or so. And there is a strong temptation often to go for the long range reader. ""They must be better, no?"

The short answer is that after 25 years in the business, we are struggling to come up with a single instance where the long range is justified, and where the desired result can't be achieved more effectively by a different configuration.

But if a reader is available that can do long range, why not? Several reasons. First, long range readers are more expensive. Second, they sometimes use more power, which means shorter battery life, and they can also respond more slowly. Last point, a barcoded label to be read at thirty feet needs to "subtend the same angle to the reader". Which means that it is a big label, perhaps two or three feet wide. So long range readers are available, but be cautious about building them in to your system.

Connection technology

Bluetooth

Simple and convenient, but some desktop workstations don't have bluetooth, and it can be fiddly to set up and maintain.

Cordless

The preferred method for connection. Very convenient, but a slight penalty on pricing. Usually plug it in and it works. The reader is usually charged through the base station, so if the computer is turned off overnight, there may be a few minutes delay while the battery charges first thing in the morning. An external power supply resolves this if it is a problem.

USB Connection

The standard for a tethered reader. Limits are mobility, as when trying to read labels on the far side of a pallet. Also, over time, the cable can become worn from constant movement. It is for this reason that we usually recommend cordless readers.

It is possible to cascade barcode readers, but some special setup is required.

Wedge Readers

Were used at one time to read bar coded information directly into a desktop computer. To install a wedge reader, the user disconnected the keyboard (after turning power off), and plugs the keyboard cable into the wedge reader.

To the system unit, there is no difference between the user typing "123" and the user scanning a bar code printed with the number "123". Wedge readers are a very easy and flexible way to add bar code function to an existing system. They have now mostly been replaced by readers that connect through the USB port, or even by bluetooth.

Serial Connection

Usually for very specific applications. Some careful set up required. Also, a special piece of software needs to be loaded and set to be always running in the background. Not recommended, unless there is no alternative.

To learn more about barcodes:


for Barcodes and Barcode technology

for how to choose the best reader

for how to choose 1D or 2D barcodes

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SageData is based in Ottawa, Ontario, Canada.

We design, supply and support systems built around RFID, Barcodes and Handheld computers.

For further information, or for advice and assistance with your application, contact Doreen Wallace or Keith Jackson.

Click here to reach SageData by email.

To reach us by phone:
from outside Ottawa, dial 1-888-838-1067
from Ottawa, dial 613 225 4404

Thank you for your interest in our products and services.bar

SDSQAP - SDSREF7126

Barcode readers tethered Symbol LS2208
Barcode Reader, Cordless, from Symbol
Barcode printers

Barcode Labels

Barcode and RFID labels
Asset Management with RFID or barcodes
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