TECH TALK | QR codes: behind the matrix of those little black and white squares

It's more popular now than ever, but did you know the QR codes had been around since 1994. Picture: Shutterstock.
It's more popular now than ever, but did you know the QR codes had been around since 1994. Picture: Shutterstock.

Back in 2015 I thought I was being very clever with my business cards.

Handing out a 90mm by 55mm card with my details on it seemed a little old-fashioned in a modern digital age.

But many people still believed business cards were the single greatest marketing tool available.

To try and modernise the concept, I printed a QR (quick response) code on the back of my cards (complete with part of our logo embedded).

The idea was that I could hand my business card to any person with a smartphone and they could simply use the QR code to correctly enter all my details in to their contacts list.

Sounds incredible ... but before March this year, the sum total of people who actually used my QR code was approximately one. Me!

Despite the fact that QR codes had been around since 1994, when I turned my card over to show people what was on the back, I normally received a blank stare.

Maybe they just didn't want my details?

COVID-19 changed all of that.

With contact tracing at cafes and QR codes compulsory from November 23 in NSW at all hospitality venues, the public is certainly more familiar with QR codes.

I thought I should explore the technology behind the matrix of black and white squares.

Before the QR Code was the barcode.

Patented in 1951, the barcode was based on the concept of Morse code, but was initially an invention for commercial use.

In 1974 the first universal product code (UPC) was scanned on a pack of Wrigley's chewing gum.

Before this time, a checkout employee would enter the amount of each item into a cash register and it would sum the cost of the items. All stock control was a manual process and errors were easily made.

The UPC allowed a unique 12-digit number to be assigned to all products (12 digits allows one trillion unique barcodes) and the automation of the supermarket checkout process had begun.

To understand what occurs when a barcode is scanned, it effectively simulates a human typing in 12 digits on a keyboard and pressing enter.

The main limitation is the amount of information able to be stored. Some barcodes only allow numeric data while others allow alphanumeric.

Some barcodes allow a maximum length of 80 characters but more commonly barcodes represent just 12 and they are typically numeric.

If all you want to do is record and read 12 numeric characters, a barcode is for you.

With the realisation that there are times when you need significantly more information, the QR code offered significantly increased density.

With a maximum of 4296 alphanumeric characters, it gives significantly more scope to allow the easy entering of detailed information.

The QR code was initially used to track vehicles and components during the manufacturing process.

While some people have expressed concern about privacy issues and a fear of QR codes when they enter their local cafe, the QR code itself is harmless.

It is effectively a string of letters and numbers written in a format that a computer can easily translate.

When you walk in to a cafe, the owner could just as easily have a website address that you need to manually type into your smart phone to enter your details for the purpose of contact tracing.

The website address is not to be feared, but if you have concerns, it's more likely with what happens to your information after you enter it.

Tell me if you think people will now start scanning the back of my business card at

  • Mathew Dickerson is a technologist and futurist and the founder of several technology start-ups.