What is NFC Tag Reader? How to Use It? [Android & iOS]

Near Field Communication is also called NFC. It is a protocol used by two devices (like two phones or watches) to wirelessly communicate when placed close to each other. The NFC protocol is quite similar to RFID (Radio-Frequency Identification) but with a much shorter range (usually 4 CM or 1.5 inches, whereas, at maximum 10 CM or 4 inches). NFC can be categorized as a mixture of RFID and Bluetooth but does not require device discovery like Bluetooth. Also, RFID is a one-way communication protocol, whereas, NFC is a two-way communication protocol.  

A Brief History of the NFC Protocol

NFC got famous in 2020 with the Coronavirus pandemic but is under development since 1983 in form of RFID and NFC was approved as an ISO standard in 2003. NFC was first introduced in 2006 in a Nokia phone and Samsung joined the ship in 2010 when released the Samsung NEXUS S Android phone with NFC support. The protocol was adopted by Apple in 2014 on the release of the iPhone 6. The NFC protocol is the barebone of the contract-less payments mechanism. As a rough estimate, there are around 2 billion NFC-enabled devices (phones, laptops, etc.) and around 20% of the world’s population can access NFC.

Working and Usage of NFC Protocol

To use NFC, both NFC-enabled devices (e.g., phones) are placed within a few CMs of each other and can exchange information wirelessly. The following is a brief list for which NFC may be used:

Types of NFC Devices

Many modern phones (like Android phones, iPhones, etc.), smartwatches, some laptops, etc. are nowadays equipped with built-in NFC capabilities. Android phones above version 4.4 may have this capability. iPhone 6 and above may also have NFC built-in. Apple TV also has NFC support. Even Nintendo Wii U, Nintendo 3DS, and Nintendo Amiibo range also have support for NFC. Adidas has equipped Telstar 18 soccer ball with an NFC chip to facilitate players to communicate with the ball through their phones.

NFC Tags

The beauty of NFC protocol is that only one of the devices is required to be powered on and the other device can be unpowered/passive while using radio waves from the powered device. This paves the way for NFC tags. NFC tags have a storage memory (in bits), along with a radio chip that is attached to an antenna.

NFC tags are powerless chips that draw their power from the magnetic induction of the other-powered NFC device. These little tags don’t require a power source or battery. Due to this, the most basic function for which an NFC tag may be used is as a replacement for old QR codes.

NFC tags can be attached to any real-world object like a product to track a store’s inventory. NFC tags can be programmed with any information and then attached to any product, which can be read through another NFC-capable device (like a smartphone or smartwatch). For example, an NFC or smart tag may be embedded into a flyer of a political figure and when scanned through another NFC device, the candidate’s website may be shown, touting the candidate’s credentials and biography. So, basically, there is practically no limit on the possible uses of NFC tags. NFC tags can be in form of stickers, wristbands, etc. A cute example of NFC tags is Nintendo’s Amiibo figures, when scanned by the console, a user may get items, special characters, or additional context, depending on the figure or game.  

The type and size of the information on an NFC tag depend on the memory capacity of the tag used. Till now, there are five types of NFC tags, type 1 to type 5, differing in storage capacities, read/write capabilities, data transfer speeds, etc. Any person can buy NFC tags and program them with their required data. Only NFC tags of type 1 to type 3 are rewritable, although, a user/manufacturer can configure it to be read-only.  

Working Mechanism of an NFC Tag

The basic working mechanism of an NFC tag is similar to an RFID tag as it uses radio waves to communicate with the other NFC device. These radio waves from the powered NFC device query the NFC tag for the information and the tag drawing power through these waves sends back the encrypted signal which is then validated on the powered NFC device to complete the information exchange. An NFC tag can only communicate with one NFC device at a time.

NFC Tag Reader

To retrieve information from an NFC tag, a user is required to use an NFC tag reader. Unlike RFID, where specialized RFID readers are used (like on a store’s front door to keep check of the store’s inventory), a user may not require a dedicated NFC tag reader, his smartphone or smartwatch may be enough. Some users may require to install an app to scan an NFC tag, whereas, the feature may be built-in into their phones. Apple has equipped its iOS with App Clips to facilitate its users in using specialized NFC tag readers. Do not get confused with the word reader, many of the NFC Tag readers can not only read from a tag but also can write to the tag as well. The data transferred between an NFC tag/reader is encrypted and is in NFC data exchange format.

Working Mechanism of an NFC Tag Reader

As discussed already, the NFC tag readers need power (from a battery or power source) to read data from the NFC tag. To do so, an electric current is passed through the reader’s coil, which generates an electromagnetic field around the reader. Once an NFC tag comes in close proximity to the reader, inductive coupling between the tag and reader coils occurs (Faraday’s law of induction). Due to this coupling, the tag is powered on and the data transfer occurs by using a technique called Manchester Coding. This coding technique determines binary values from the tag’s electromagnetic pulses and these values are converted to human-readable data. This whole process may occur in seconds.

Using Mobile Phone an NFC Tag Reader

Contactless payment terminals are one of the most used NFC readers but common users may prefer to use their mobile phones to scan NFC tags.

Use an Android Phone as an NFC Tag Reader

1. Launch the Android phone Settings and open Connected Devices.

   

2. Now select Connection Preferences and check if NFC options are shown.

   

3. If so then the phone supports NFC.
4. Now tap on NFC and enable it.
5. Then bring the phone closer to the NFC tag and if the phone natively supports it, you may see the tag data on your phone’s screen.
6. If the phone does not natively support NFC tag reading, launch the Play Store and install an NFC reader app (like NFC Tools, Tiger, etc.).

   

7. Now launch the NFC reader app and use it to scan the NFC tag.

Use an iPhone as an NFC Tag Reader

iPhone uses two types of NFC scanning, In-App Tag Reading (the user manually scans the NFC tag) and Background Tag Reading (the iPhone automatically scans for the NFC tags in the background).

1. Launch the iPhone Settings and select General.

   

2. Now open NFC and enable it.

   

3. Then hit the back button till the iPhone Settings menu is shown.
4. Now open Control Center and add the NFC Tag Reader to Included Controls.

   

5. Then swipe down on the iPhone screen and tap on the NFC Tag Reader to enable it.

   

6. Then bring it near to the NFC tag and the tag’s data will be shown on the phone’s screen.

Create Your Own NFC Tags

NFC tags are fairly cheap products and anyone can program them to perform different tasks. A blank NFC tag (which can be easily ordered online), an NFC-compatible device (e.g., your smartphone), and an NFC programming application are the requirements to program an NFC tag. NFC Tools, Tiger and NFC TagWriter by NXP are a few examples of such applications that can be used to program an NFC tab. A user may use these applications to create creative NFC tags e.g.,  a user may place an NFC tag near his bedside and when going to sleep, he can put his phone to silent mode by simply scanning the NFC tag (which is configured to put the phone into the sleep mode).  Also, a user may program an NFC tag to hold his Wi-Fi SSID and passphrase. When a guest asks for the Wi-Fi credentials, just ask the guest to scan the tag and after scanning, his device will join the Wi-Fi network. These are just examples; a user can program NFC tags the way he likes and they are limitless uses of NFC tags. An iPhone user may use Automations in Shortcuts to use NFC tags on the next level.