A barcode reader is a scanner that by means of a laser reads a barcode and emits the number that shows the barcode, not the image.
There are two kinds of readers: fixed beam and mobile beam. In both cases a light source illuminates the surface of the code. Being the bars dark and the spaces light, these will reflect more light than the bars. The reflected light is detected by a photosensor element, producing the clear spaces a greater electric current in the photosensor element. For the reading to progress, there must be a relative movement of the code with respect to the reader or vice versa, or there must be a laser beam that moves to explore the code. This makes the difference between the two classes of readers cited.
The electric current that circulates through the photosensor is proportional to the intensity of the reflected beam (which is the census magnitude), which as in the case of the scanner is an analog signal. Therefore, it will need to become digital (ones and zeros) to be processed.
Different types of readers:
- Manual reader:
They are shaped like a pen, it must be moved from the entire length of the code, so that a fixed beam can be reflected and censused. - Fixed slot reader:
The operator must move the code through a slot in the reader. It is fixed beam. - Fixed reader with mobile laser beam:
An orange-red laser beam sweeps the barcode tens of times per second in one direction. A laser beam is directed by a moving mirror, which in turn directs the beam towards other mirrors. Through the output window it seems as if many laser beams are generated. This allows you to read a barcode that is in different spatial locations with respect to the cited window. These readers are more accurate than the previous ones.
