Diode Driver

Barcode Wands

Barcode wands were the first broadly used types of barcode readers. How does such a barcode wand work? In the tip of the wand you'll find a small LED (light emitting diode) and a photo receptor. The light is reflected from the code into the receiver. From the signal pattern of the reflection the wand can determine the type and content of the barcode. Reading a barcode with a wand is simple but requires some practice. There is no trigger button, basically the wand is "always on" when connected to a PC. Then user holds it like a pen and moves it quickly from left to right to left over the barcode.

Barcode CCD Scanner

It's almost certain that most scanners today are of the Charge Coupled Device (CCD) scanning type. A good CCD Barcode Scanner for less than USD 100 will easily outperform a wand and at times even a laser scanner that costs two or three times as much. A CCD scanner is like an "expanded wand". Where wands have just one light emitting diode and one receiver, CCD scanners have a complete row of those elements. By triggering the scanner the whole code is illuminated and exposed to the receiving elements. Scanning barcodes with a CCD scanner is faster and more reliable than with a barcode wand.

Barcode Laser Scanner

Laser scanners have their name from a laser diode in the scanning head or "scan engine" as it is sometimes called. The beam is projected through a system of lenses and mirrors onto the barcode, resulting in a visible single red line or pattern of lines. Laser scanners have two modes of operation: They can be used in a stand and will trigger automatically if a barcode is held in front of the scanner. This can be very useful because it keeps the personnel's hands free and is one of the real pros of laser scanners. Out of the stand these devices use a trigger button much like a CCD scanner to trigger the scanning process.

Barcode Imager

Two dimensional or area barcodes have gained much popularity in recent years. With a 2D barcode it's possible to encode up to 3,000 bytes of information in a single barcode symbol the size of a stamp. However, this progress comes with a notable drawback: Ordinary barcode scanners will not read this type of barcodes. To scan area barcodes, so called barcode imagers are required. These scanners basically work like a digital camera, that is they take an image of the barcode, decode and process the encoded data and transmit the data to the host computer.

Connecting a Barcode Scanner to a Computer

PCs still outnumber Macs by far so it comes as no surprise that most scanners use an interface that will only connect to PC's: A keyboard wedge. Basically a keyboard wedge is a "Y" shaped cable that connects the scanner, the keyboard and the PC. Everything the scanner sends looks to the computer as if the user have typed it into the keyboard. Drivers are not required, the installation is child's play.

For Macintosh computers or laptops without keyboard ports, a connection via USB is the only viable alternative.

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Article from FOLD.COM - Your source for Barcode Information and Know How.

Article Source: ArticlesBase.com - Choosing The Right Barcode Scanner

Part 2 - Tutorial - Measuring Current on the rkcstr MICRO-DRIVE Laser Diode Driver