How Do Barcodes Actually Work?

Have you ever visited a supermarket or a small store and noticed a little rectangle with black lines and some numbers at the bottom? If so, you may have wondered about its purpose. You're in the right place! This page will explain how barcodes work, from being scanned by a barcode reader to how the data is used on a computer. But first:

What is a Barcode?

A barcode consists of a combination of black and white lines that vary in width and spacing. These codes are read by a barcode reader, which decodes the information stored within them. Barcodes typically hold data such as IDs, names, and item descriptions. When scanned, the barcode reader retrieves this information from a database to process transactions or look up details.

Barcodes have many types, and UPC (Universal Product Code) is the most widely used of the others in the picture below.

These are the most popular types of barcodes

How does the Barcode reader work?

The barcode reader (Also called an optical scanner) has a specific way of interpreting the strips that are on the barcode, depending on its type. The most popular is the CCD (LED scanner), followed by Laser and pen readers. However, this is outside the scope of this post.

The barcode consists of white and black bars (spaces), which are translated by the Barcode Reader, depending on the reader type, the barcode reader reads the barcode usually using a laser or a red light that is then translated by the strength of luminance to analog and then to digital (binary) using an Analog-to-Digital Converter ATD. These electrical charges are then translated into zeros and ones and passed to the computer or by using a wire connection, Bluetooth, Wi-Fi, USB, and even APIs to transfer data. The computer then takes these values and decodes them into an ID or number using the Character Encoding Standard, which depends on the barcode type, mostly Code 128, EAN-13, UPC, or ASCII.

How the bars are converted; source 

A simple example of how the bar reader works (laser), Source: https://www.explainthatstuff.com/barcodescanners.html

There are 7 components of a UPC barcode; The first component is the Left Guard Bars, whose purpose is to mark the beginning of a barcode, the second one is the Right Guard bars, it's basically the opposite of what the former does, Next coming is The Number system character 0, it indicates the type of product that has the barcode (UPC-A barcodes) E.g., 0 or 1 is for regular retail products, 2 is for variable weight items like produce, etc. 

Furthermore, Center bars are intended to separate the numbers of Manufactory number and the item number which acts as unique identifiers for the items from the same manufacturer and is also assigned by the origin factory. Lastly, there is the check digit, which is a number generated using a calculation that includes other numbers In the bar code, It checks if the manually entered numbers are correct or not otherwise More components collaborate in the barcode, but these are the fundamentals.

There is another very similar and competitive alternative of representing data as machine-readable patterns, a QR code (matrix (2D) codes), You can learn more about QR Codes here

Conclusion 

Barcodes are an important part of saving data in modern commerce and logistics, making the retrieval of data trivial, especially when it comes to computers, they allow the data to be stored in a tiny rectangle and then read by a matching barcode reader. Barcode readers helped significantly in reducing checkout time and tracking inventory since the data is being passed through computers. 

After understanding how barcodes work, we should appreciate what technology has served us, saving us hours and days from doing trivial tasks with this ubiquitous tool. While new advancements like QR codes have expanded the possibilities of data storage, traditional barcodes continue to play a vital role in simplifying and streamlining processes in commerce and logistics.

Thanks for reading

Web AI was used to correct some information