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What are QR Codes & NFC Tags?

QR Codes

What are QR Codes

A QR code (abbreviation for Quick Response code) is a specific matrix barcode (or two-dimensional code) that is readable by dedicated QR barcode readers and camera phones. The code consists of coloured (usually black) modules arranged in a square pattern on a white background. The information encoded may be text, web site or other data.

Common in Japan, where it was created by Toyota subsidiary Denso-Wave in 1994, the QR code is one of the most popular types of two-dimensional barcodes. The QR code was created to allow its contents to be decoded at high speed.

Although initially used for tracking parts in vehicle manufacturing, QR codes now are used in a much broader context, including both commercial tracking applications and convenience-oriented applications aimed at mobile phone users (termed mobile tagging). QR codes may be used to display text to the user, to add a vCard contact to the user’s device, to open a website, or to compose an e-mail or text message. You can generate and print your own  own QR codes for free here.

How it works

A user would take their reading device most likely a mobile phone with a camera and scan (take a picture) of the code with an application designed to read QR codes – here’s our recommended QR Code applications. This application then reads and interprets the data to provide the information contained. The process is easy you can see our demonstration here.

Technical Diagram of a QR Code

How much data can they hold?

QR Codes can hold a lot of data which is why they are so useful however pushQR minismises the data in the code for faster more accurate scanning and stores the data in our engine.

Numeric code Max. 7,089 characters
Alphanumeric Max. 4,296 characters
Binary (8 bits) Max. 2,953 bytes
Kanji/Kana Max. 1,817 characters


A major benefit of QR Codes

QR Codes can be generated with the ability to deal with scenarios where some of the QR code image is disturbed. This make them very robust. Here’s how much data can be missing and still allow it to work!

Level L 7% of codewords can be restored.
Level M 15% of codewords can be restored.
Level Q 25% of codewords can be restored.
Level H 30% of codewords can be restored.


NFC Tags

What are NFC Tags?

NFC technology is very common these days and features in most high-end smartphones. NFC tags can be used to store and transfer information. You will probably  have noticed small NFC tags next to advertisements near bus stops, stickers in shops, or may have even come across NFC enabled business cards.

These tags can store wide ranges of information, from short lines of text, such as a web address or contact details, to links to apps in the Apple App Store or Google Play Store. It’s a quick and efficient way to quickly push information to your phone and these little tags can replace Bluetooth in some cases. So here’s how it works.

How it works

NFC tags are passive devices, which means that they operate without a power supply of their own and are reliant on an active device to come into range before they are activated. The trade-off here is that these devices can’t really do any processing of their own, instead they are simply used to transfer information to an active device, such as a smartphone.

In order to power these NFC tags, electromagnetic induction is used to create a current in the passive device. Without getting technical the basic principle is that coils of wire can be used to produce electromagnetic waves, which can then be picked up and turned back into current by a another coil of wire. This is very similar to the techniques used for wireless charging technologies, albeit much less powerful.

The active devices, such as your smartphone, are responsible for generating the magnetic field. This is done with a simple coil of wire, which produces magnetic fields perpendicular to the flow of the alternating current in the wire. The strength of the magnetic field can be adjusted by varying the number of turns in the wire coil, or increasing the current flowing through the wire. However, more current obviously requires more energy, and very high power requirements would not be desirable for use in battery powered mobile technologies. Hence why NFC operates over just a few inches, rather than the many meters that we’re used to with other types of wireless communication.

The passive device works in the same way, just in reverse. Once the passive device is in range of the active device’s magnetic field, the electrons in the receiving coil of wire begin to produce a current that matches that in the transmitting smartphone. There is always some power lost during transmission through the air, but over short distances the current generated is enough to power the circuitry in the NFC tag.

These circuits are fine tuned to a certain frequency, which increases the device’s sensitivity to charging frequencies. This allows for a maximum transfer of energy across the air. Once the tag is powered up, it can sync up and send data over the 13.56MHz NFC transmission frequency at either 106, 212 or 424 Kbps, just like your regular NFC communication between phones or other larger devices.

Different Tag Types

NFC tags communicate using the ISO 14443 type A and B wireless standards, which is the international standard for contact-less smartcards, used on many public transportation systems. This is why NFC devices can be used with existing contact-less technologies, such as card payment points.

There are a range of different tag types available, each offering different storage levels and transfer speeds. Tag types 1 and 2 come with capacities between just a tiny 48 bytes and 2 kilobytes of data, and can transmit that information at just 106 kbit/s. Although that may sound quite small, especially compared to your typical SD card, that’s enough data for some very simple pieces of information, such as a website URL, and is all you need for most basic NFC tags. These tags are designed to be highly cost effective, and can also be re-used if you want to change the data stored on them.

Type 3 uses a different Sony Felica standard, and can transfer data at a slightly faster 212 kbit/s. These tend to be used for more complicated applications, but sadly can’t be rewritten.  Similarly, type 4 is again read-only, but has a larger memory capacity of up to 32 kbytes and communication speeds of between 106 kbit/s and the maximum NFC 424 kbit/s. Tag type 4 works with both type A and B of the ISO14443 standard.

Cheap and effective

The strongest argument in favour of NFC, over other forms of short range wireless communication, is that tags are incredibly cheap to make and maintain, but can still be used for a wide range of applications. With very simply circuitry and very few components, NFC tags can be produced on mass for very low unit costs.

Combine low costs with the absence of any power requirements, and you have a cheap yet effective way of quickly communicating with other smart devices. From launching applications, to exchanging web addresses and purchasing a rail ticket, NFC aims to make our lives that little bit more convenient just by using our smartphones.