NFC technology is quite common these days. It is used on most high-end smartphones. Along with the latter, for storing and transmitting information, you can use small NFC tags. What it is? You probably noticed small tags next to advertisements near bus stops, stickers in stores, or even met the modern idea of using NFC-enabled business cards.
These tags can store a wide range of information - from short lines of text, such as a web address or contact information, to links to applications on the Google Play store. This is a quick and efficient way to quickly transfer information to your phone, and these small tags can replace bar codes and QI codes, and in some cases even be used instead of Bluetooth.
How does it work?
How does it work and what is it? NFC tags are passive devices. This means that they operate without their own power source and depend on the active device that enters the coverage area before they are activated. Their peculiarity lies in the fact that these devices cannot actually perform any processing of their own; instead, they are simply used to transfer information to an active device, such as a smartphone.
To power these NFC tags, electromagnetic induction is used to create current in a passive device. The basic principle here is that wire coils can be used to produce electromagnetic waves, which can then be captured and converted into current by another coil. This is very similar to the methods used for wireless charging technologies, although much less powerful.
How is the connection?
Active devices, such as your smartphone, are responsible for generating a magnetic field. This is done using a simple coil of wire, which creates magnetic fields perpendicular to the flow of alternating current in the wire. The magnetic field can be adjusted by changing the number of turns in the coil of the wire or by increasing the current flowing through the wire. However, it is obvious that more current requires more energy, and very high power requirements are undesirable for use in battery-powered mobile technologies. This is the reason why NFC only works on a few centimeters, and not on many meters, which are standard for other types of wireless communications.
A passive device works the same way, just the opposite. As soon as it is in the range of the magnetic field of the active device, the electrons in the receiving coil of the wire begin to generate a current that matches the current in the transmitting smartphone. During power transmission, some power is lost, but at short distances the current generated is sufficient to power the circuit in the NFC tag. What does it mean?
These circuits are tuned to a specific frequency, which increases the sensitivity of the device to the charging frequency. This allows maximum energy transfer through the air. After turning on the tag, it can synchronize and send data with an NFC transmission frequency of 13.56 MHz at a speed of 106, 212 or 424 Kbps, as with normal NFC communication between phones or other larger devices.
Different types of tags
What is an NFC tag and how to use it? They exchange data using the wireless standards ISO 14443 Type A and B, which are the international standard for contactless smart cards used in many public transport systems. That's why NFC devices can be used with existing contactless technologies, such as card payment points.
Different types of tags are available, each of which offers different storage levels and transfer rates. Tag types 1 and 2 have a capacity of 48 to 2 kilobytes of data and can transmit this information at a speed of just 106 kbit / s. This may seem like a pretty small amount, especially compared to your regular SD card, however, this data is enough to transfer very simple pieces of information, such as a website URL and the like. These tags are designed with high economic efficiency in mind and can be reused if you want to change the data stored on them.
NFC payment terminals are becoming more common as consumers begin to use Android, Apple and Samsung Pay. These are NFC bank tags that allow contactless payment.
Type 3 uses a different standard - Sony Felica - and can transmit data at a slightly faster speed, 212 kbps. They are usually used for more complex applications, but, unfortunately, cannot be rewritten. Similarly, Type 4 is read-only again, but has a larger memory capacity of up to 32 kbytes and data rates from 106 kbps to a maximum NFC of 424 kbps. Label type 4 works with both Type A and B of ISO14443.
Applications
Some programs for NFC tags are designed to configure the user's phone according to location (for example, quiet mode when placed on the nightstand), others are for public use, for example, publishing web content about the location.
This programming is entirely done on tags. Depending on the security settings, any compatible phone will have the same response when you click on the tag. If the tag’s response is “Like” on Facebook or something similar, this is done using the phone’s user credentials (for example, Facebook’s credentials) and not the tag’s identifier.
For example, Samsung’s NFC tags work under four headings:
- Settings
- Telephone.
- The Internet.
- Social networks.
In more detail, it looks like this.
Settings:
- Turn on silent or car mode.
- Set an alarm.
- Launch the application.
- Join a Wi-Fi network. This can be used to provide convenient access to cafe networks.
- Show message.
Telephone:
- Make a call.
- Send text.
- Share vCard Contact.
The Internet:
- Open web page.
- Show location on a map service such as Google maps.
- Register at Foursquare or other location-based services.
Social networks:
- Update Facebook status with location.
- Like on Facebook.
- Send a tweet.
- Subscribe to Twitter user.
Tags can also be pre-programmed and distributed to users. Such a label can be set to redirect to the manufacturer’s technical support page and send product information to those interested. Labels prepared at the factory can also be printed with logos or molded in addition to stickers such as key rings or bracelets.
Tag life
The reprogramming of NFC tags is claimed for more than 100,000 cycles. A tag placed on a doorway or bulletin board can be reprogrammed in place and thus can have a long life (for example, for conferences, meetings or events). Tags can be locked after adjustment to avoid unauthorized reprogramming. Locked tags can only be unlocked by the phone that set the lock.
The duration of the relevance of a locked tag will be the main limitation of its lifetime if unlocking is not possible. Label life is also likely to be limited by physical factors such as adhesive adhesion or peeling complexity.
Compatibility
TecTile is not installed by default on modern devices. If the tag is read before it is installed, the user is redirected to the application download site.
To use Samsung TecTile NFC, you need a device with the MIFARE Classic chipset. This chipset is based on the NFC NXP controller, which does not comply with the NFC Forum standard. Thus, to use TecTile, an NXP chipset is required, otherwise the NFC tag is not supported.
It is found on many Android phones today. However, recently, manufacturers decided to abandon TecTile support. In particular, in the latest flagship phones Samsung Galaxy S4 and Google Nexus 4, the service is missing. Also, the application does not work with BlackBerry and Windows phones. This means that some types of NFC tags are not supported at all.
Other versions
The new version of TecTile, called TecTile 2, has improved compatibility, but currently the Samsung Galaxy S4 is the only device that has its built-in support. It is not supported on other Samsung devices.
NFC tag types that comply with the NFC Forum Type 1 or Type 2 compatibility protocols are much more widely compatible than MIFARE-dependent Samsung TecTile, and are also widely available.
Popular standards for NFC tags are NTAG213 (137 bytes of used memory) and Topaz 512 (480 bytes of used memory).
Tag encoding
The need for an installed application is one of the drawbacks of TecTile and NFC tags in general. Basic standards support labels that carry URLs, where the scheme or protocol can be either http (for web addresses), or a telephony number, or an anonymous data scheme. Although basic phones can assume support for http and tel schemes, reading others will not be available if the application is not installed and registered to process them.
How to record?
NXP TagWriter is a general service for writing and reading NFC tags for a smartphone, which is recommended by specialists and is available in the Google Play app store. It has only a few basic functions, such as writing, reading, erasing, and deleting tags. All this makes it easy to use and understand even for novice users. A distinctive feature of this application is the options that it offers when writing a tag. The following are all the formats and features available for writing to the tag:
- Business card.
- Wi-fi
- Link / URL.
- Bluetooth.
- Email address.
- Geographical position.
- Phone number.
- Launch the application.
- Simple text.
- SMS
How to record an NFC tag? To do this, you will need:
- Smartphone supporting NFC.
- NXP TagWriter (free download).
- NFC tag (only open type, not protected and not blocked).
Create custom tags with NFC
Since launching websites is considered to be one of the most common ways to use NFC tags, consider an example of recording a link so that when you click on a tag using an NFC-enabled smartphone / device, it will request the right URL.
- Open the NXP TagWriter service and select Write Tag.
- The menu displays the following parameters:
- New dataset.
- My data sets.
- Write from CSV.
- Copy label.
- Copy the QR code.
Further manipulations:
- Select New Dataset.
- Since you are planning on writing down the URL / link, click on the “Link” position.
- If you want to add a title for your link in the Description field, enter the appropriate entry. If not, do not fill out this field.
- “URL Type” should read “Website URL.”
- Find “Site URL” below and enter the estimated value in the box that says “Login to the site.” The address must begin with the characters "https: //" for correct operation.
- The “Add UID tag (mirror)” field is an option that adds a unique tag identifier at the end of the URL so that you can track how many users used this NFC tag to visit your site. This is a great feature if you have multiple tags with the same URL, and you want to know which ones work better. If you do not need this tracking feature, do not fill out this field.
- The “Add interaction counter (mirror)” field below is an option that adds an increasing number to the end of the URL whenever anyone interacts with this tag. For example, if person A interacts with the label first, the URL will add “1” at the end; later, when user B touches the tag, the URL will add “2” at the end and so on. If you do not want to use this function, just leave this field blank.
- Next, click "Save and write."
On the next screen, your content will be displayed at the top, and you will be presented with the options described below:
- Record several NFC tags (one at a time) - check the box next to this position if you want to record the same content in several tags one by one.
- Protection - check this box if you want your NFC tag to be protected. When you set this option, several variations will appear with different levels of protection:
- Soft Protection - disables tag rewriting by another user;
- Password protection - your tag will be read-only and can only be rewritten with the password that you create. When this option is selected, another window will appear prompting you to create a password.
- Tag Lock - This option makes the tag read-only and can never be overwritten. If you select this option, check your content several times before writing a tag.
- Confirm overwrite - this checkbox must be selected every time if you write a tag so that it is possible to delete irrelevant data and write new ones.
Then you need to perform the following actions:
- After you have marked the fields that you want to add to your tag, click "Save."
- After that, a pop-up window will appear on the screen with the inscription "Ready to save or share the selected content." Here, hold the NFC tag and attach it to the back of the smartphone.
- When the label is pressed on the back panel of the device, another screen will appear with the message “Confirm overwrite” with a button at the bottom that will say “Touch to confirm saving”. Press this key while holding the NFC tag on the back of the phone.
- After a few seconds, a confirmation screen appears with the inscription “Record successfully”, which means that you have successfully written the data to the label.
The above instruction allows you to record an NFC tag for a bank card and other functionalities.
Final word
The strongest argument in favor of NFC compared to other forms of short-range wireless communications is that tags are incredibly cheap to manufacture and maintain, but can still be used for a wide range of applications. With very simple circuitry and few components, NFC tags can be mass produced for very low unit costs.
This allows you to get a cheap but effective way to quickly communicate with other smart devices. From launching applications to exchanging web addresses and buying train tickets, technology aims to make your life a little more convenient using your smartphones. This is the biggest plus of NFC tags. What does it mean?
Given the deployment of mobile payment methods that can use NFC, more and more smartphones support this connection. Do not be surprised if you see how an increasing number of these small labels will appear everywhere.