# Exploring QR Codes: Unraveling the Technological Secrets Behind Scanning Sensors

### INTRODUCTION

Nowadays, QR codes have deeply integrated into various industries, serving as vital tools for product tracking, mobile payments, product registration, account login, and more. However, many people still have questions about the working principles of QR code scanners.

### STORY

How does a QR Code Scanner work?
Well, to get that, first we have to learn the basic encoding mechanisms of QR codes.

In encoding, QR code cleverly uses the concept of "0" and "1" bitstreams that form the ba-sis of the computer's internal logic. Several geometries corresponding to binary are used to represent alphanumeric information, which can be read by a QR code scanner to realize information processing.

· Position Detection Patterns: tell a scanning device the orientation of the QR code and mark the boundary of the encoding character.
· Timing patterns: determine the coordinate of the modules in the QR code.
· Alignment pattern: correct the distortion of QR code.

· Format information: decode a QR code, and it contains the error correction level of the code and the chosen mask pattern.

· Data and error correction keys: designed for storing the actually saved information and error correction codes to correct errors caused by QR code damage

The information is converted into binary codes according to certain rule, and then they will be filled into the Data and Error Correction Keys area based on the specific algorithm.

Fill the area with the mask patterns and a QR code is generated.

What is amazing about QR codes is that they can be read by a scanning device even though a part of the code is damaged. What’s the secret behind this?

Well, the answer is Reed-Solomon Code. Reed-Solomon error correction is a forward error correction code. It works by oversampling a polynomial constructed from the data.

In short, the generated QR code has a strong error correction capability after using Reed-Solomon Algorithm. When scanning a QR code, this scanner module uses CMOS to read the QR code image, and decode the black and white squares to translate the patterns on the QR code into human-readable data.

### PRODUCTION

This is a QR Code Scanning Sensor introduced by DFRobot. It can read bar codes or QR codes with a scan speed of 15m/min. The sensor has a small size and high-efficiency recognition, and can be easily integrated into various industrial equipment and applications.

The scanner is equipped with a 0.3megapixel camera and auxiliary lights, white light illumination, and red light focusing. This helps the module to effectively identify codes in low-light environments. Besides, it offers TTL-232 and USB(HID-KBW) communication interfaces, plug and play.

### PRACTICAL APPLICATION

Install a QR code scanning sensor on a conveyor belt of the assembly line. All the products are labeled with QR codes.

When the QR scanner scans a QR code label, and the relevant product information will be recorded for subsequent registration.

### CONCLUSION

In summary, by delving into the encoding mechanism of QR codes, we have unveiled the operational principles of QR code modules and witnessed their practical application on factory assembly lines. Whether it's for product registration or production process monitoring, QR code sensors play a crucial role.

Do you know any other interesting applications of QR codes? Feel free to share them with us in the comments. If you have any questions or suggestions, please leave a comment and let us know!