How do QR codes work?

Many supposedly modern technologies can trace their origins back to a time before the internet, even though they require connectivity to function.

The barcode was developed in the early 1950s, based on Morse Code, but it took two decades to establish itself as a method of representing data in a way machines could easily read.

Similarly, QR codes were created in the 1990s by a Toyota subsidiary called Denso Wave Incorporated, for tracking vehicles and parts.

An abbreviation of Quick Response code, these agglomerations of black squares were directly inspired by barcodes.

They rely on the same principle of clarity, enabling machines to instantly scan and accurately identify coded information.

However, barcodes have to be a certain size to be legible. The amount of information they can hold is therefore limited.

QR codes took the concept of binary data storage understood by computers (on or off, black or white) to another dimension – vertical and horizontal, rather than simply horizontal.

Thanks to Denso Wave’s decision to make this technology freely available, they’ve become widely adopted around the world after receiving ISO approval in 2000.

And despite issues with devices sometimes failing to recognise a QR code (especially on coloured backgrounds or at smaller sizes), these codes have become widely adopted.

Speaking in code

A QR code replicates a barcode’s pricing data functionality, though its ability to store hundreds of times more data means it can perform other roles its ancestor is incapable of.

It can purchase or promote goods and services, direct devices to a specific web address, trigger the sending of emails or connect a device to a WiFi network.

A QR code can be scanned upside down or at an angle, with three of its corners featuring solid squares that tell a viewing device which way round the data should be interpreted.

Every code contains a unique assortment of black squares, which often form shapes when they’re positioned beside each other in significant numbers.

It’s possible to generate patterns, add colours or overlay graphics, though this is purely visual and doesn’t affect the information contained in each matrix of squares.

The code is viewed through a smartphone or tablet’s in-built camera, using an app that interprets the data and processes instructions based on it.

For instance, a QR code on a travel pass will identify your booking, seat number and personal information, letting you through security gates and allowing staff to direct you appropriately.

A specific QR code might reflect the source of a customer enquiry. That’s useful for marketing campaigns, which is why they’re commonly seen in adverts and literature.

Indeed, the ability to track and analyse traffic represents one of their greatest advantages.

Each code is generated randomly and can be created for free, while consumer apps to view QR codes are readily available in both the Android and iOS app stores.