QR code: How does it work? Simple explanations and practical uses

The QR code, or Quick Response code, is a tool that has become ubiquitous in our daily lives. Whether it's to make a payment, access a restaurant menu, or honor the memory of a loved one with digital souvenirs, QR codes simplify access to information. Their popularity has exploded in recent years thanks to their versatility and ease of use.

In this article, we will explore in detail how QR codes work , their structure, ways to scan them, and their many applications. The goal is to provide you with a clear and practical understanding of this essential tool.

What is a QR code?

Technical definition

A QR code is a two-dimensional barcode that can hold a large amount of information. Unlike traditional barcodes, which only store linear data (such as numbers), QR codes can incorporate complex information such as URLs, text, GPS coordinates, or even Wi-Fi connection data.

Difference with a classic barcode

The main differences between a QR code and a barcode are:

• ✔ Storage capacity : A QR code can contain up to 7,089 digits or 4,296 alphanumeric characters, much more than a traditional barcode.
• ✔ Easy to read : QR codes can be scanned in any orientation thanks to their specific markers.
• ✔ Versatility : They allow the integration of various types of data (text, web links, etc.), unlike barcodes which are limited to digital information.

Origin and invention

The QR code was invented in 1994 by the Japanese company Denso Wave to meet the logistics needs of Toyota. Initially designed to track automotive parts, it quickly found applications in various industries thanks to its ability to store and transmit information quickly.

How does a QR code work?

QR code structure

A QR code is made up of several elements:

• ✔ Positioning Patterns : Three large squares located in the corners allow the scanner to identify the orientation of the code.
• ✔ Alignment Patterns : Small squares ensure accurate reading even if the code is slightly distorted.
• ✔ Modules : Black and white dots contain data in binary form.
• ✔ Error correction : Up to 30% of the code can be corrupted without compromising its readability thanks to built-in redundancy.

Generation process

To create a QR code, the desired information (e.g. a URL) is converted into binary data. This data is then organized into modules according to a specific algorithm to form the final pattern.

Reading by a scanner

When a smartphone or reader scans the QR code:

• 1. The camera captures the image of the code.
• 2. The software identifies positioning patterns to determine orientation.
• 3. The modules are analyzed to extract the binary data.
• 4. Data is decoded and translated into actionable information (e.g. opening a web page).

How to scan a QR code?

Native apps on iOS and Android

Most modern smartphones have a native app for scanning QR codes via the camera:

• ✔ On iOS : Simply open the Camera app and point it at the QR code. A link or action will automatically appear.
• ✔ On Android : Many devices also offer this feature in their default camera app.

Third-party applications

If your device doesn't have a native app, you can download third-party apps like "QR Code Reader" or "Barcode Scanner". These tools often offer additional features like scan history.

Precautions to take

• ✔ Avoid suspicious QR codes : Do not scan codes from untrusted sources to avoid the risk of phishing.
• ✔ Check URLs : Make sure the link displayed corresponds to the expected site before clicking.
• ✔ Protect your personal data : Never provide sensitive information after scanning an unknown QR code.

What are the types of QR codes? Advantages and disadvantages

Static vs Dynamic

• Static QR codes : The information is fixed and cannot be modified after creation (example: a permanent URL).
• Dynamic QR codes : They redirect to a modifiable URL, allowing you to update the content without changing the code itself. They are ideal for marketing or event management.

Common types

• ✔ Textual : Displays text directly after scanning.
• ✔ URL : Redirects to a web page.
• ✔ vCard : Allows you to easily add contact details to a directory.
• ✔ Wi-Fi : Connect directly to a network without entering the password.
• ✔ Payment : Used to make transactions through apps like WeChat or PayPal.

Advantages vs Disadvantages

Use cases of QR codes in daily life

Marketing and advertising

QR codes are transforming marketing by directly connecting the physical and digital worlds. By scanning a QR code, consumers instantly access promotional sites or special offers. Dynamic QR codes allow real-time tracking of campaign effectiveness and user engagement. Each advertising medium thus becomes an interactive and measurable touchpoint.

Payments and banking transactions

QR codes simplify contactless payments, offering a fast and secure alternative. Apps like Lydia or PayPal allow instant transactions by scanning a QR code. This method is very popular in China with WeChat Pay, and is gaining popularity in France, offering a practical and hygienic option.

Health and safety

QR codes facilitate quick access to vital information in the healthcare field. Health passes in the form of QR codes have made it possible to manage access to regulated areas. Medical alert bracelets equipped with QR codes allow first responders to quickly access a patient's medical history, improving the accuracy of interventions.

Digital Memorials and Memories

At Inoubli@ble, we use QR codes to offer a unique experience: each personalized photo frame includes a QR code that links to an interactive biography retracing the life of the deceased through photos, videos and texts. A timeless and modern way to preserve memory.

Conclusion

The QR code is much more than a simple black and white square; it is a powerful tool that simplifies our access to information while adapting to a multitude of practical uses. Whether in commerce, health, or even to honor the memory of a loved one, its use has become essential.

With the constant evolution of digital technologies, the potential of QR codes continues to grow. Their increased personalization and role in securing data promise even more innovative applications in the years to come.

So whether you are new to QR codes or are used to them, it is clear that they will continue to play a central role in our connected daily lives!