Barcode scanners can be extremely simple devices consisting of a light source, a picture diode along with a simple decoder or complex CCD or camera based scanners. Find out how barcode scanners work and how to scan barcode scanner in a computer.
There are currently four several types of barcode scanners available. Each uses a slightly different technology for reading and decoding a barcode. You can find pen type readers (i.e. barcode wands), laser scanners, CCD readers and camera based readers.
Pen type readers consist of a light source as well as a photo diode which can be placed next to each other in the tip of a pen or wand. To see a barcode, you drag the tip of your pen across all of the bars in a steady even motion. The photo diode measures the intensity of light reflected back in the light source and generates a waveform which is used to study the widths of the bars and spaces from the barcode. Dark bars in the barcode absorb light and white spaces reflect light so that the voltage waveform generated by the photo diode is surely an exact duplicate from the bar and space pattern within the barcode. This waveform is decoded with the scanner in a manner just like the way Morse code dots and dashes are decoded.
Laser scanners work exactly the same way as pen type readers with the exception that they use a laser beam because the source of light and typically employ either a reciprocating mirror or possibly a rotating prism to scan the laser beam to and fro all over the barcode. Just similar to together with the pen type reader, a photograph diode is commonly used to look at the power of the light reflected back from the barcode. Within both pen readers and laser scanners, the sunshine emitted through the reader is tuned to your specific frequency along with the photo diode is made to detect only this same frequency light.
Pen type readers and laser scanners are available with some other resolutions to enable them to read barcodes of various sizes. The scanner resolution is measured by the size of the dot of light emitted through the reader. The dot of light should be comparable to or slightly smaller than the narrowest element width (“X” dimension). When the dot is wider compared to width from the narrowest bar or space, then a dot will overlap 2 or more bars at any given time thereby inducing the scanner to be unable to distinguish clear transitions between bars and spaces. When the dot is simply too small, then any spots or voids from the bars can be misinterpreted as light areas also making barcode companion unreadable. The most widely used X dimension is 13 mils (roughly 4 printer dots on the 300 DPI printer). Because this X dimension is indeed small, it is quite crucial that the barcode is produced using a program that can cause high resolution graphics (like B-Coder).
CCD (Charge Coupled Device) readers use a range of countless tiny light sensors lined up consecutively in the head from the reader. Each sensor might be regarded as an individual photo diode that measures the power of light immediately facing it. Each individual light sensor in the CCD reader is incredibly small and as there are hundreds of sensors lined up consecutively, a voltage pattern identical to the pattern within a barcode is generated in the reader by sequentially measuring the voltages across each sensor within the row. The most important distinction between a CCD reader plus a pen or laser scanner is the CCD reader is measuring emitted ambient light through the barcode whereas pen or laser scanners are measuring reflected light of your specific frequency originating from the scanner itself.
The fourth and newest type of barcode reader available today are camera based readers designed to use a small camera to capture a graphic of any barcode. Your reader then uses sophisticated digital image processing strategies to decode the barcode. Video cameras make use of the same CCD technology as with a CCD barcode reader with the exception that rather than developing a single row of sensors, a relevant video camera has a huge selection of rows of sensors arranged in a two dimensional array so they can generate a graphic.
The factors that will make a barcode readable are: a satisfactory print contrast in between the light and dark bars and having all bar and space dimensions in the tolerances for that symbology. It is also useful to have sharp bar edges, few or no spots or voids, an even surface and clear margins or “quiet zones” at either end of the printed symbol.
All application programs support barcode reading so long as you hold the right equipment. Barcode readers can be purchased with two types of output – either “keyboard wedge” output or RS232 output. The barcode readers with keyboard wedge output plug into the keyboard port on your personal computer additionally they give a pigtail connector to enable you to plug in your keyboard concurrently. If you scan a barcode using the keyboard wedge barcode reader, the data explores the computer just as whether it were typed in on the keyboard. It is then extremely easy to interface the barcode reader to your application which is written to just accept keyboard data.
The keyboard wedge interface is extremely simple however it has a few drawbacks. If you swipe a barcode, the cursor has to be within the correct input field inside the correct application otherwise you wind up reading barcode data into whatever application offers the focus. This can cause all sorts of potential problems as you can imagine. The keyboard output is also limited for the reason that you are unable to modify your data in any way before sending it into the program that may be to obtain the information. As an example, when you required to parse a barcode message into multiple pieces or remove a few of a barcode message or add in the date or time stamp you would be unable to by using a normal keyboard wedge reader.
One other possible output option is to get a barcode reader by having an RS232 or “Serial” interface. With these sorts of barcode readers, you connect the reader to a available serial 65dexqpky on the back of your computer. You will then need a program termed as a “Software Wedge” to accept data from the barcode reader and feed it on the application where you want the data to visit. The disadvantage to this approach is that it might be a more advanced nevertheless, you gain a lot more control of how and where your information winds up whenever you read barcode sled.
Our WinWedge product line is designed just for this purpose. WinWedge is undoubtedly an executable program that will pass serial data to and fro to many other programs using either DDE (Dynamic Data Exchange) or by converting incoming serial data to keystrokes (i.e. it stuffs the keyboard buffer using the incoming serial data). With WinWedge, you may control specifically where the data goes in the objective application and you will also perform a number of modifications about the data before it can be shipped to the application form including parsing or translating the data and also adding additional keystrokes or date and time stamps on the data.
WinWedge is very simple to operate and is made to have you ever ready to go sending and receiving serial data from inside your application in just a few minutes. Because WinWedge can pass data using DDE, you may set your application up to insure that this barcode data always goes where it should certainly go and you can also have your application running in the background still accept barcode input as you run various other program within the foreground. WinWedge is without question the most robust way to interface a barcode reader to a PC with the least amount of effort.