Getting Started with NFC
8
NFC is specied by the NFC Forum, http://nfc-forum.org/, which promotes the
implementation and denition of the NFC standards for interoperability of devices and services.
The biggest differences among the common RFID technologies are the communication distance,
which is limited to about 10 centimeters, and the ability for bidirectional communication.
By now, you are probably thinking, why do I need another adapter on my smartphone? This will
be another battery-draining feature that most probably will be disabled most of the time. Well,
that's not exactly the case when we talk about NFC. It is specially designed to have a very
small battery consumption footprint so that it can be enabled all the time, thus avoiding the
annoying rituals of enabling and disabling the adapter when we need to use it.
However, you might think you can't send large amounts of data; that's true, but it doesn't
matter! We already have other good and reliable alternatives such as Bluetooth or Wi-Fi Direct
for that. So, why would we need another super-fast, battery-drainer adapter? With NFC, things
are kept simple. There's no need to pair devices, it can be constantly turned on, and it takes
less than one-tenth of a second to establish a connection between devices.
Then you may think that what you really want is to keep the battery consumption low and
still be able to transfer bigger les. In cases like these, we can use the best of both worlds.
For example, we can use NFC to transfer a small data block that contains the necessary
information for a successful Bluetooth pair, then turn Bluetooth on, pair the devices, transfer
the les, and turn it off again. All of this is done automatically and with a seamless user
experience. That too with just one tap!
NFC communication can be established between two NFC-enabled devices or between a
device and a tag. One of the entities in the communication process will act as active and
will be responsible for sending, reading, or writing the data, and the other will act as passive.
There are three main operation modes:
f Reading and writing: In this mode, a device reads and writes data to/from a tag.
f Peer to Peer (P2P): In this mode, a P2P connection is established between
two devices.
f Host Card Emulation (HCE): In this mode, a device emulates the behavior of a
tag/card. For example, we can use our smartphone as if we are using several
payment cards.
This book will focus only on the rst two modes. HCE is available from Android 4.4 KitKat,
onwards and you should have a look at this amazing feature at http://developer.
android.com/guide/topics/connectivity/nfc/hce.html
In this rst chapter, we will create a very simple application that will allow us to cover the rst
steps needed in all applications that use NFC, as well as cover how to set up a working virtual
testing environment.
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