Barcode: how it works

Technology is part of our daily life and this has been happening for several decades now, well before computers and smartphones had the popularity they enjoy today. Think, for example, of the technology behind barcodes , which has been used since the mid-1970s and is still widely used today.

Speaking of the barcode, have you ever wondered what lies behind how it works? If you are reading this guide, you probably are. Well, know that this could be the right opportunity to satisfy this curiosity: in the next paragraphs, in fact, I will be able to show you how the barcode works and how to exploit this historic technology even on the most modern portable devices.

What do you say? are you ready to start? Yup? Fantastic! Then make yourself comfortable and take all the time you need to focus on reading the next few paragraphs. I sincerely hope that, in the end, you will be satisfied with what you have learned.


  • What is the barcode and what is it for
  • How to read barcode
    • QR & Barcode Scanner (Android / iOS / iPadOS)
    • Other apps to read barcode
    • Barcode reader

What is the barcode and what is it for

Let’s get straight into the topic and see  what a barcode is and what it’s for . Basically, the barcode is an  identification code  consisting of a set of high contrast graphic elements that can be read through a  scanning sensor  (but also with  a smartphone camera ) and decoded to read the information. which contains.

To simplify matters as much as possible, barcodes are codes designed to mark products and allow their automatic recognition at the checkout, in order to speed up payment operations and avoid queues at the exit of the shops. They are formed by  spaces  and  black areas (the  bars , in fact). By space we mean the clear element of the code, which separates two bars from each other (the black elements). Each code also has one or more modules, which is the width of the narrowest element (bar or space). It is thanks to these spaces that readers are able to read barcodes and decipher the information they contain.

Norman Joseph Woodland and Bernard Silver, two engineering students of Drexel University at the turn of the 1940s and 1950s, developed the idea of ​​the barcode. Large-scale adoption, however, came only later: the first key date is March 31, 1971 , when a group of leading companies agreed to use a “universal code” for product identification. Thus was born the identifier that today is called GTIN ( Global Trade Item Number ), but the real turning point came two years later, on April 3, 1973 , when the UPC symbol ( Universal Product Code ) was approved ; it was in fact then that the bar code was born that we know and still use today.

In 1977 the aforementioned codes were also adopted in 12 European countries, including Italy. Thus was founded the EAN , a non-profit organization for identification standards, based in Brussels. That organization then called its name and today it is known as GS1 .

In 1978 Indicod was born , which can be defined a bit like the “Italian division” of GS1, which at the time was made up of 60 associated companies. Today that association has taken the name of GS1 Italy and is one of 115 GS1 non-profit organizations active in 150 countries around the world that promote the use of GS1 standards. It is, therefore, the only body in Italy authorized by GS1 to issue company prefixes and GS1 barcodes (EAN) and, at present, brings together 35,000 consumer goods companies, facilitating a better relationship between companies, associations, institutions and consumers.

The numbers speak for themselves: there are now 6 billion GS1 codes scanned every day, 100 million products that have a GS1 code and about 2 million companies , from the largest to the smallest, that use them globally.

But how do companies use barcodes? I’ll explain it to you right away. As GS1 Italy illustrates on its official website , it only takes 5 steps to start using GS1 (EAN) barcodes .

  1. GS1 system membership. Once the registration to the system is completed, which can be done directly online and takes a few minutes, you will receive: an Excel sheet with 1,000 unique and authentic numbers for the creation of EAN-13 codes for fixed weight products; the company prefix GS1 (thanks to which it is possible to develop the codes for the packages / cartons, the codes for the pallets and the codes for the physical entities GS1 GLN), the credentials to access the private area and the online tool Coding to generate the codes bar; the certificate in English of belonging to the GS1 system valid internationally; three free checks; free participation in courses on basic GS1 coding and a practical guide for the correct use of GS1 codes.
  2. Assigning GS1 barcodes to products. By accessing the GS1 Italy Codifico online tool, you can assign a code to each product in your personal data. It is important to remember that each product and each variant must have unique codes, that each commercial unit different from the others must be assigned a new and unique GTIN (EAN-13 code) and that the codes must never be changed (at least until the products do not undergo such changes that lead to the creation of a new business unit). It should be remembered that the owner of the trademark is responsible for the univocal identification of the goods and the management of the codes in their personal data.
  3. Barcode printing. Also using the GS1 Italy Codifico online tool, you can generate the EAN barcode (the graphic image of the bars) for your products, download it and then print it to label your products. Clearly, each type of code requires special programs and printing methods. It is therefore necessary to make sure to operate correctly according to the code to be printed, as there are precise rules to be respected in terms of size and positioning of the symbol; furthermore, the correct reading of the printed code must always be guaranteed.
  4. Choose the size of the barcode. The size of the symbol in the drawing depends on the symbol chosen, the application and the printing method chosen. For example, the EAN / UPC symbols differ from those ITF-14 and GS1-128 because they allow reading by omnidirectional scanner and, therefore, have a fixed relationship between base and height. When one dimension is changed, the other dimension must be proportionally altered with magnification factors ranging from 150% to 200%. The ITF-14 and GS1-128 symbols also have defined zoom factors, but in this case the size of the zoom factors are often specified by the width of the X dimension rather than the zoom values.
  5. Choose an appropriate color scheme. Barcodes are typically printed in black on a white background, in fact this is the best combination to allow readability by readers, but in reality others can also be used. The important thing is that the bars are dark in color and consist of a single line of color (they should not be printed using multiple imaging tools). Light or “reddish” colors (as scanners use red light beams) can be used as a background with solid colors.

For all the details, I renew the invitation to visit the GS1 Italy website , where you will find all the details on what it takes to create the barcodes and where, of course, you can subscribe to the GS1 system in just a few clicks.

For completeness of information, it must be said that there are also other types of barcode in addition to the GS1 (EAN) one, such as the Pharmacode one  used for the identification of drugs and the Universal Product Code , used instead to mark the products imported from United States, United Kingdom, Canada, Australia and New Zealand.

Among the  two-dimensional barcodes, the increasingly widespread adoption of QR codes should be emphasized  : the square-shaped codes widely used in the digital world, which can contain links and information of various kinds to be scanned with the camera of the smartphone or tablet. I told you about it in more detail in another guide ).

How to read barcode

After analyzing, in broad terms, the technology behind the operation of barcodes , it is time to see how to read the codes in question.

How do you read a barcode?  The most reliable technology employs a  laser beam reader , usually combined with an  oscillating head and sometimes a  mirror system , which increases the accuracy of the reader. The cheaper readers, on the other hand, use an  LED bar  to illuminate the barcode and a  CCD  ( Charged Coupled Device ) sensor .

In some areas, such as those connected with some industrial sectors, an image acquisition technology  provided by a video system is also used  which, with the help of suitable software, allows you to take a photograph of the product on which it is applied. the barcode and recognize, read and interpret the code itself.

Below, therefore, you will find explained how to read barcodes through convenient apps for smartphones and tablets or through hardware code readers used for the purpose, more precise and faster.

QR & Barcode Scanner (Android / iOS / iPadOS)

One of the best barcode reading apps is QR & Barcode Scanner . As easily understood from its name, it is a solution that is able to read not only barcodes but also QR codes . It is available as a free download for Android (from the Play Store or from alternative stores ) and iOS / iPadOS . Please note that its free version features (non-invasive) advertising banners that can be removed by purchasing the full version, which costs € 4.49.

After installing and starting QR & Barcode Scanner, grant the app permission to access the camera of the device on which you have installed it and accept the conditions of use of the service by pressing the Accept button (this is necessary only on Android).

Subsequently, if you use the Android version of the app, frame the barcode of your interest and, when this is captured by the app, press the Search product , Search book or Search content button (depending on the type of product on which the code itself is applied), so you can see what lies behind the code itself. By pressing the Share button , however, you can share the code that has been read through the available options.

If you use the iOS / iPadOS version of QR & Barcode Scanner, however, after making sure that Scan is selected (top left), frame the code of your interest. Then press the Procuct search button if the code is attached to a product, Web search if it concerns a Web content or Book Search if it concerns a book. To share it, instead, tap on the Share item and select one of the sharing options from those available.

Other apps to read barcode

In addition to the one mentioned in the previous chapter, there are many other apps for reading bar codes . Below you will list some that might be right for you.

  • ScanPro( Android / iOS / iPadOS ) – is a very powerful document scanner which, if necessary, can also be used for reading QR and bar codes. Basically it is free, but the advanced functions are available by subscribing to a subscription, which starts at € 6.49 / month.
  • Barcode Scanner( Android ) – it is a free app based on the open source ZXing libraries through which you can scan barcodes and QR codes in a simple, fast and free way.
  • com( Online ) – it is a Web application through which it is possible to read barcodes (and not only) by uploading the image that contains them or by specifying the URL of the latter.

For more information on how to use these and other barcode reading apps , I refer you to the reading I have dedicated to the latter.

Barcode reader

As I told you earlier, there are also devices that act exclusively as barcode readers . How do you say? Are you very intrigued by the latter and, therefore, would you like to know how a barcode reader works ? I try to explain it to you briefly.

Well, these devices usually use a laser (or similar technology) to “read” the alternating lines and blanks in barcodes. Then they send the collected data to a decoder which, after analyzing them, translates them into information and data, according to the standard used.

Depending on the model of player purchased, after connecting it to the USB port of your computer, it may be necessary to download drivers from the manufacturer’s website or a client that allows it to function correctly. If you want, you can find more information on the website of the manufacturer of the reader that you will eventually purchase (or with a simple search on Google ).

There are various types of barcode readers on the market. In essence, however, they are divided into three major categories.

  • Laser readers– this is the most popular type of reader and, probably, that’s what you thought of before coming to this guide. This type of reader uses a red diode laser to read the reflectance (ie the ability to reflect light) of the black and white spaces of the barcode. They can only read standard linear barcodes (1D).
  • Linear imager readers– this is also a standard 1D linear barcode reader, whose operation differs from that of laser readers, in that instead of reading the light reflected by the laser, they take an image of the barcode itself.
  • 2D imager readers– the operating principle of these readers is similar to that of linear imager readers, but as their name suggests they allow reading not only 1D, but also 2D codes. These scanners are capable of reading barcodes regardless of their position and direction, which makes them much faster than laser scanners and linear imagers.

The prices of these devices can also vary a lot. The cheaper ones cost a few tens of euros; the more advanced ones (which are also the most precise and fastest ones), on the other hand, can cost more than 100 euros. They can be found in the most well-stocked electronics stores and online stores, such as Amazon .

by Abdullah Sam
I’m a teacher, researcher and writer. I write about study subjects to improve the learning of college and university students. I write top Quality study notes Mostly, Tech, Games, Education, And Solutions/Tips and Tricks. I am a person who helps students to acquire knowledge, competence or virtue.

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