QR codes are among the most disruptive tools in audience engagement today. They have allowed businesses to transfer information to users in a matter of seconds. QR codes have also proven highly effective and beneficial during the COVID-19 pandemic as a contract tracing tool. But how do QR codes work?

QR codes work like barcodes. While barcodes are usually scanned using price scanners, you scan QR codes using a smartphone camera. You will then be redirected to a web page where the data within the QR code is presented in human-readable format.

What Are QR Codes?

QR codes are square-shaped images composed of tiny black-and-white pixel patterns. QR codes are like barcodes but have a broader scope in usage since they can store data other than product-related information.

The series of tiny black-and-white squares represent specific bits of information that is otherwise unreadable to humans without scanning the code.

What Does “QR” in QR Code Stand For?

“QR” in QR code stands for “quick response” code, aptly called because users can scan it in a split second using a smartphone or any scanning device. After scanning, they will instantly have access to the data the code contains.

How Did QR Codes Come About?

QR codes were invented in 1994 by Denso Wave, a subsidiary of Toyota. The company was producing barcode scanners at that time, making it aware of the limited features of barcodes. While barcodes were useful for cashiers, as they don’t have to type in long product codes for items customers purchase, their use cannot be expanded to include other data types. 

A development team from Denso Wave was tasked to create a two-dimensional code that could store more data, and they came up with QR codes. The company also used the technology to track vehicles and their parts, making QR codes helpful in the car manufacturing industry.

How Are QR Codes Structured?

QR codes are made up of tiny black squares that almost look like dots on top of a white background. You can also see three large squares on three corners. These squares are called “modules” and they represent a specific type of data.

For example, the large squares in the upper left, upper right, and bottom left corners of most QR codes represent a detection pattern called “finder patterns.” On the other hand, the tiny squares determine the number of rows and columns a code can contain. For example, the latest version of the QR code is version 40. This version contains 31,329 modules (squares) that help hold, send, and encode data.

What Are the Different Sections in a QR Code?

The image below shows the common structure of QR codes.

structure of QR codes

A deeper understanding of the QR code structure can enable you to decode one manually. The video below shows an example of how to do this tedious task:

How Is Data Encoded in QR Codes?

QR codes use four combinations of coding modes converted into a two-dimensional arrangement of squares or modules. These coding modes stand for bytes, kanji, numeric, and alphanumeric characters.

The modules go through a process called “masking” to avoid errors, which entails switching the colors. If the color is light, it should be changed to a darker one, and if it’s too dark, it should be changed to a lighter one.

The four-bit indicators select the encoding mode and convey other data. Sometimes, QR symbols can be mixed up, depending on the encoding mode used. The number of characters encoded in a specific mode will be shown in a length field after every indicator, and the numbers shown depend on the encoding and symbol version.

How Do QR Codes Store Data?

Traditional barcodes only store data horizontally. However, QR codes store data horizontally and vertically, holding over a hundred times more information. QR codes store data using the four encoding modes mentioned above.

QR codes are widely used today. They can be used to transfer money, track packages, share information, such as recipes and grocery lists, and grant access to wireless networks.