How barcode scanners work is a common question as few items purchased nowadays do not have a barcode. The black parallel lines that make up the barcode have information about the item. So how is the information from those black lines read and turned into understandable data?
To read the barcode a barcode code scanner has to be linked up to a computer, either with a cable or via a wireless. But how does it all work?
The scanner beams a red light across the barcode. The light is reflected to the illumination system which is detected by the scanner. An analogue signal is produced which in turn is fed to the converted which turns it into a digital signal. The technical work is then done by the barcode scanner’s decoder which performs a variety of tasks. It confirms that the barcode is decipherable. The decoder then converts the information into ASCII text which is then formatted and sent to the computer.
The important parts of the barcode scanner are its illumination system, sensor or converter and decoder.
The light which scans the barcode is the generated by barcode scanner’s illumination system. Illumination systems differ between the different types of scanner.
The sensor and convertor is composed of a photo detector which senses the light reflected back from the barcode. An analogue signal is generated. The voltage of this signal fluctuates depending on where the light landed on the barcode. The black lines absorb light, while the white spaces reflect it.
As with the illumination system the technology of the sensor differs according to the type of barcode scanner. But in all cases the job of the sensor is to cover the target – in this case the barcode – and then send the analogue signal to the converter.