The magic behind the QR code
Lesson summary
Hi there everyone, I’m Jeff and this is Plain English, where we help you upgrade your English with current events and trending topics. You’re listening to the slow recording of Plain English. If you want to listen to the fast version, you can do that by joining as a Plus member. All the details are at PlainEnglish.com/Plus .
JR is the producer and this is lesson number 425. That means the full transcript and the rest of today’s lesson can all be found at PlainEnglish.com/425.
Coming up today… QR codes. They’re simple and convenient. Just open your phone’s camera, point it at the confusing black and white square, and the link pops up on your phone. But have you ever stopped to think about how those codes work? That’s what we’ll talk about today. The expression we have for you is “the naked eye.” And JR has a song of the week. Let’s get going.
History and magic of QR codes
We’ve all seen them: these confusing, black-and-white square codes that we’re supposed to scan with our smartphones to open a link in our browsers. They look like crossword puzzles, but without any letters or numbers in them.
QR codes have exploded in popularity in recent years, popping up on marketing posters, receipts, restaurant tables, smartphone apps, COVID testing centers, bus tickets, and more. These square-shaped, black-and-white codes are indecipherable to the naked eye . But they contain the information needed to open a web page on a browser, and therefore to do anything that can be done with a single string of text or numbers.
A QR code is just one type of code called a 2-D barcode. Two-dimensional, or 2-D barcodes, are an improvement on the old-style single-dimension barcodes of the past. You know the kind: they’re on almost all prepackaged products at your supermarket; they’re on shipping labels; and they’re on parts in a factory.
The old barcodes were developed in the 1960s and were a horizontal pattern of black lines on a white background; the thickness of the lines corresponded to a number. It made reading numbers easy for special scanners. It eliminated the need for a person to type numbers into a database when tracking things, like at the checkout line at a store. A machine can read a barcode in a fraction of a second. Barcodes became popular in the 1980s and helped many businesses become more efficient.
But barcodes have some limitations. First, they only contain numbers, not text. Second, if you want a long number, you need a really long barcode. And third, to read barcodes, you needed a special type of scanner. Oh, and they also had to be read horizontally; you can’t rotate a barcode 90 degrees.
2-D barcodes are an improvement in almost every way. They are squares or rectangles with black-and-white dots and shapes that can relay information to a scanner. What type of information? A 2-D barcode can contain letters, numbers, and special characters. You can fit more information into a 2-D barcode than you can into an old-fashioned one. That’s why 2-D barcodes are so useful: they can generate longer strings of information, like highly complex web site URL’s.
What’s more, they’re space-efficient. They can be scanned upside down, backwards, or at an angle. They can transmit 300 times more information in the exact same amount of space as a traditional barcode. 2-D barcodes can be read by a smartphone, something almost everyone has. And smartphone cameras can now read the 2-D codes and open a browser if the codes correspond to a URL.
There are many types of 2-D barcodes, but the most common is called the QR code. The technology was developed by a subsidiary of Toyota, the Japanese carmaker. They were looking for ways to improve the process of vehicle assembly and were frustrated by the limitations of a traditional barcode. The technology to generate the codes is quite valuable, but the patent holders decided to make the coding behind QR codes open source in 1994. That means that the specific way to generate and read a QR code is open to anyone; that’s why QR codes are the most popular type of 2-D barcodes.
A QR code has multiple parts. You probably noticed that most QR codes have three big squares—one in each of three corners. This tells a scanner which way is up. The corner without a big square is in the bottom-right. That way, you can scan a QR code upside down and the reader will know which way is up. A fourth, smaller square helps scanners read the code if the code is scanned at an angle or is curved.
Second, there is a region that is the same on every QR code. It’s two strips of alternating black and white squares. That helps the reader decipher the whole image in case there are distortions—for example, if it’s blurry, faded, damaged, or scanned at an angle.
QR codes come in multiple sizes; if you just need a short string of text or numbers, a micro QR code would do the trick. If you need a long string of text, such as for a complicated URL, then a larger code is necessary. The biggest code can contain either 7,000 digits of just numbers or about 4,000 characters made up of letters and numbers.
Anyone can generate a QR code for any string of text for free on the internet today. And there’s no risk of creating a duplicate code: each QR code contains the unique string of text needed to open a URL or reproduce a string of characters.
Today, QR codes have many uses. Next week, we’ll devote a lesson to the many ways that QR codes have been incorporated into our daily life—there’s at least one from Japan that you just won’t believe.
Barcode epiphanies
I remember when I first found out what a barcode did. I was a teenager and I worked at the YMCA, kind of like a community center and fitness center, in my hometown in Connecticut. I worked at the front desk, checking members in, signing new members up, answering questions, et cetera. When members would arrive, they’d scan their membership cards through a barcode reader. And I could see on the screen of the computer that all the barcode reader did was enter a number into a box in the database. And it dawned on me: a barcode is just a string of numbers!
Well I had a similar epiphany when I wrote this lesson. I thought a QR code was generated by a central company. And I thought there was limit to how many unique QR codes could be generated. For example, would we ever run out of possible QR codes? Would we ever accidentally duplicate them? It’s kind of like saying, will we ever run out of web addresses? Or, would there ever be duplicate web addresses?
The answer is no…we just make the QR codes bigger and more complicated. So in other words, the QR code is the URL in the same way that a barcode is just a number. And if you want a longer URL, you need a bigger QR code. Even the long, complicated URL’s are only a couple of hundred characters long, so we’re in no danger of running out of QR codes.
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