Barcodes, QR codes, RFID popular science articles

　　When it comes to QR codes, barcodes, and RFID, you might not know what they are. When you check out at a supermarket, the clerk scans a row of black and white vertical lines on your product—that's called a barcode; When you pay with WeChat, the square pattern made up of many squares at the counter is called a QR code. But what is this FRID tag with the English word? Shangtai is the most common, and you probably have an ID card and bank card. So, these three things appear in countless situations in our lives, but do you know how to use them? The Shangtai editor will guide studious learners to learn more.

　　Barcode

　　First, let me clarify: QR codes are symbolic markers used to record information, not for decoration! We've all seen this since we were kids. Haven't you ever suspected that Shangtai is really scary (and Radish never doubted it either). It's time for science popularization, so I'm planning to take notes in my little notebook. A barcode is a pattern composed of alternating black and white stripes. The black part is called the "strip," and the white part is called the "blank." The strip and blank represent binary 0s or 1s. Encoding them allows the combination of black-and-white patterns with varying thicknesses and spacing, representing numbers, characters, and symbolic information.

　　Barcode

　　So how do we read the information inside? Suntech

　　In barcodes, bars and empty bars have different reflectances and intensity for the same light. Simply put, black and white can be clearly distinguished. Scanners use this principle to detect different reflected light from different emission zones through optical sensors, i.e., to identify the order information of black and white.

　　Barcode scanning equipment and how to make Syntek

　　Scanning devices: There are mainly two types of barcode devices. One is read-only information, not storage; it must be connected to a computer. For example, when checking out at a supermarket, the clerk scans a QR code and the computer reads the price; The other is that it can be read and stored, and then the information can be transmitted to the computer.

　　How to make it: Generally, specialized software such as Nicelable Pro can convert numbers and letters into barcodes. For large batches, batch imports can be made using Excel. Do you want to create one yourself and try it out? Excel is also possible—just download barcode fonts (like 39HrP24DmTt) to do it.

　　Excel custom barcode

　　QR code

　　You could say QR codes are an upgraded version of barcodes. Barcodes are one-dimensional, recording only horizontal information and not vertical ones. Even if you tear the barcode in half horizontally, you can still read the information; As for QR codes, they are naturally two-dimensional, recording both horizontal and vertical directions, and are designed according to the bitstream principle of "0" and "1", available in both matrix and stacked formats.

　　Stacked: Based on barcodes, that is, multiple barcodes are stacked together as needed to form a QR code.

　　Stackable QR codes

　　Matrix type: The most commonly used QR code, encoded by the different distributions of black and white pixels (other colors as well) in the matrix. Points appearing in the matrix element area (square, circle, etc.) represent binary "1", while those missing represent "0". The information is determined by point arrangement.

　　Matrix-style QR codes

　　QR code tip: From the diagram, you can see that matrix QR codes are divided into several small areas, each containing certain information. There are three color blocks at the corners, ensuring accurate location of information no matter which direction you scan from. Personalized charts can be stored in the middle; QR codes have some error correction capability, can correct up to 30% of incorrect information, and even a small amount of broken messages is unaffected. The storage of information is dozens to hundreds of times greater than that of barcodes.

　　How to read QR codes

　　There are many of them. Mobile phones are the most widely used, such as Alipay and WeChat payments, where scanning QR codes to obtain personal and website information is very common.

　　QR code creation

　　Mass production also requires specialized software. You can use Excel 2010 or later to create your own versions. For details, refer to online tutorials.

　　RFID

　　RFID is different from barcodes or QR code patterns; it has a chip that can be read and written by specialized devices. There are two types of IC cards: contactless and contactless. The chip of a contactless IC card is directly encapsulated on the card base surface, while a non-contact IC card consists of a chip and coils. It can be divided into COB copper wire-wound wires, etched antennas, printed antennas, etc. The differences in application are: the former requires inserting a card reader during use, such as some bank cards, while the latter requires only approaching the reader's sensing antenna to be read, such as transportation cards, access cards, ID cards, etc.

　　Non-contact, our cafeteria meal card has an internal structure composed of a chip and a coil antenna.

　　The contact bank card chip is encapsulated in the card base.

　　Bank card chips

　　Working principle

　　The reader or handheld encodes the information to be sent, loads it onto a carrier signal of a certain frequency, and sends it via an antenna. The electronic tag in the reader's working area receives this pulse signal, allowing it to read the information in RFID and also write information to it. For example, when we use a meal card to swipe a meal, the amount is read first, then the meal amount is deducted, and finally the amount deducted is written down.

　　RFID production

　　By using bartender software combined with specialized coats, the information can be written into the RFID chip. As for how to make the chip, it's impossible to do it yourself—just buy one.

　　From barcodes to QR codes to RFID, technology is advancing and changing our lives, with more technologies being researched and applied, such as NFC. Security will gradually improve. Who knows how far this recognition technology will develop? Feel free to share your thoughts and discuss together.