A barcode scanner is a device that reads the barcode and converts it into numbers and letters. It is connected to a computer, that stores the numbers and letters that are decoded, using a cable via the serial port or the keyboard wedge. A decoder circuitry is present that is used to decode the image with the help of a sensor.
A barcode scanner consists of a laser source and a photo sensor. It decodes the code into electrical signals, and passes them on to the computer. The computer must have a software installed in it, which helps to convert the electrical signals to numbers and letters.
The pen-type scanners are pen-shaped and have a light source and a photo diode at the tip. The light falls on the barcode and the photo diode converts the reflected light of varying intensity in a waveform. This waveform is fed to the computer via the cable.
The laser scanner has working similar to that of a pen-type scanner, but its components are different. These use laser beams as a source of light, and reciprocating mirror or rotating prism, for detecting the reflected light.
CCD stands for charge-coupled device. It consists of an array of tiny sensors placed at the tip. The tiny sensors generate a voltage waveform and they are sequentially collected and given to the computer for conversion.
The basic difference between the pen-type and laser scanners is that, the pen-type measures the reflected light of a specific frequency, whereas the laser type measures the emitted ambient light from the barcode.
Portable data terminals are also available. These contain a Liquid Crystal Display (LCD). This portable terminal is in the shape of the palm and has an integrated scanner and a computing unit inside it.
Some factors that must be considered while buying a barcode scanner are as follows:
- Environmental conditions (harsh or mild)
- Need of a real-time system
- Distance between the scanner and the barcode
- Requirement of hands-free or hand-held scanning
- Need of continuous or periodic scanning