Creating NFC enabled applications with Qt Mobility

The scope of this presentation will cover a quick introduction to Near Field Communication (NFC) technology and how applications developers can make use of the features that NFC enables to improve the usability of their applications.

The NFC specifications define two device types, active devices and passive devices known as tags or contactless cards. In an NFC exchange there must be at least one active device, which wirelessly provides power to the passive device. Mobile devices would typically be active, however, they can also operate in so called card emulation mode. Card emulation mode enables an active device to act as a tag, even when powered off. With the capabilities of an NFC active device a mobile device can operate in three different modes enabling a range of use cases in existing and new applications.

NFC enabled mobile devices are capable of reading and writing to tags. Tags can be thought of as small data storage devices. They typically have a storage capacity of a few kilobytes, which makes them candidates as a more capable replacement for QR codes. Not only do NFC tags have the capacity to hold more data (including images and animations etc), reading them is also quicker and more reliable. Usability is also improved as NFC leads itself to an always enabled feature unlike scanning QR codes. A data exchange format (NDEF) is also specified which standardises the storage format enhancing interoperability. Proprietary data format are also supported.

Two NFC enabled mobile devices can communicate when touched together using peer-to-peer communication. As the maximum transfer speed of NFC is fairly low and the time when the two devices are within range is likely to be short the amount of data which can be reliably transferred before the connection is broken is typically small. This method of communication therefore lends itself as a means of introducing two devices in a secure manner or directly transferring a small amount of data, for example a v-card. For example NFC can simplify the device selection task when transferring content between two devices. Replacing the Bluetooth scan, select, authorise steps with a single touch.

When operating in card emulation mode a mobile device can function as a replacement for many smart cards that one is likely to be carrying around, such as NFC enabled credit cards and electronic tickets for public transport systems.