Barcode scanners can be quite simple devices consisting of a light source, an image diode and a simple decoder or complex CCD or camera based scanners. Learn how barcode scanners work and the ways to scan bluetooth barcode right into a computer.
There are currently four various kinds of barcode scanners available. Each uses a slightly different technology for reading and decoding a barcode. There are pen type readers (i.e. barcode wands), laser scanners, CCD readers and camera based readers.
Pen type readers comprise of an easy source along with a photo diode which are placed next to each other within the tip of a pen or wand. To learn a barcode, you drag the tip of the pen across each of the bars in a steady even motion. The photo diode measures the concentration of the light reflected back from your source of light and generates a waveform which is used to appraise the widths from the bars and spaces within the barcode. Dark bars within the barcode absorb light and white spaces reflect light so that the voltage waveform generated through the photo diode is an exact duplicate from the bar and space pattern inside the barcode. This waveform is decoded by the scanner in the manner the same as the way Morse code dots and dashes are decoded.
Laser scanners work much the same way as pen type readers although they prefer a laser beam because the source of light and typically employ either a reciprocating mirror or a rotating prism to scan the laser beam forward and backward across the barcode. Just just like with all the pen type reader, a photo diode can be used to look at the intensity of the lighting reflected back from your barcode. Within both pen readers and laser scanners, the light emitted with the reader is tuned to some specific frequency as well as the photo diode is designed to detect only this same frequency light.
Pen type readers and laser scanners are available with assorted resolutions to allow them to read barcodes of several sizes. The scanner resolution is measured by the size of the dot of light emitted from the reader. The dot of light must be equivalent to or slightly smaller than the narrowest element width (“X” dimension). When the dot is wider in comparison to the width of your narrowest bar or space, then a dot will overlap several bars at a time thereby resulting in the scanner to struggle to distinguish clear transitions between bars and spaces. In case the dot is too small, then any spots or voids from the bars could be misinterpreted as light areas also making barcode companion unreadable. By far the most commonly used X dimension is 13 mils (roughly 4 printer dots with a 300 DPI printer). Simply because this X dimension is very small, it is quite crucial that the barcode is generated having a program that can cause high definition graphics (like B-Coder).
CCD (Charge Coupled Device) readers use an array of countless tiny light sensors lined up in a row inside the head of the reader. Each sensor can be looked at as one particular photo diode that measures the concentration of the sunshine immediately before it. Every person light sensor from the CCD reader is quite small, and as there are hundreds of sensors arranged in a row, a voltage pattern just like the pattern within a barcode is generated from the reader by sequentially measuring the voltages across each sensor within the row. The key distinction between a CCD reader and a pen or laser scanner is that the CCD reader is measuring emitted ambient light from your barcode whereas pen or laser scanners are measuring reflected light of any specific frequency caused by the scanner itself.
The 4th and newest type of barcode reader currently available are camera based readers designed to use a tiny video camera to capture a photo of the barcode. The reader then uses sophisticated digital image processing solutions to decode the barcode. Video cameras use the same CCD technology as with a CCD barcode reader other than instead of using a single row of sensors, a video camera has numerous rows of sensors arranged inside a two dimensional array in order to generate a photo.
The factors that make a barcode readable are: a good print contrast involving the light and dark bars and getting all bar and space dimensions throughout the tolerances for your symbology. It is additionally helpful to have sharp bar edges, few or no spots or voids, a smooth surface and clear margins or “quiet zones” at either end from the printed symbol.
All application programs support barcode reading providing you have the right equipment. Barcode readers can be purchased with two kinds of output – either “keyboard wedge” output or RS232 output. The barcode readers with keyboard wedge output plug into the keyboard port on your PC and they also give a pigtail connector so that you can connect your keyboard concurrently. Once you scan a barcode with all the keyboard wedge barcode reader, the info explores your computer equally as when it were typed in on the keyboard. This makes it extremely simple to interface the barcode reader for any application that may be written to take keyboard data.
The keyboard wedge interface is quite simple however it possesses a few drawbacks. In the event you swipe a barcode, the cursor needs to be from the correct input field within the correct application otherwise you find yourself reading barcode data into whatever application has got the focus. This may cause all kinds of potential issues obviously. The keyboard output is also limited for the reason that you cannot modify the info at all before sending it to the program that is to get the data. For example, if you necessary to parse a barcode message into multiple pieces or remove a number of a barcode message or add in a date or time stamp you would probably struggle to using a normal keyboard wedge reader.
Another possible output option is to find a barcode reader having an RS232 or “Serial” interface. With these types of barcode readers, you connect the reader with an available serial 65dexqpky on the rear of your personal computer. You would probably then require a program known as a “Software Wedge” to take the data from the barcode reader and feed it on the application that you want the data to go. The disadvantage to this approach is it is a bit more advanced nevertheless, you gain far more control of how and where your data eventually ends up when you read barcode sled.
Our WinWedge product line is designed just for this purpose. WinWedge is surely an executable program that could pass serial data backwards and forwards 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 together with the incoming serial data). With WinWedge, you can control specifically where the information goes into the marked application and you will also perform a number of modifications about the data before it is actually brought to the application including parsing or translating your data and also adding additional keystrokes or date and time stamps to the data.
WinWedge is very simple to use and was created to have you ever working sending and receiving serial data directly from in your own application in just a matter of minutes. Because WinWedge can pass data using DDE, you may set your application up to insure the barcode data always goes where it is supposed to go and you could also have the application running from the background still accept barcode input as you run a few other program within the foreground. WinWedge is without question by far the most robust method to interface a barcode reader into a PC together with the least level of effort.