RFID – Radio-frequency identification

Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves. Active tags have a local power source (such as a battery) and may operate hundreds of meters from the RFID reader. Unlike a barcode, the tag need not be within the line of sight of the reader, so it may be embedded in the tracked object. RFID is one method for Automatic Identification and Data Capture (AIDC).

RFID tags are used in many industries, for example, an RFID tag attached to an automobile during production can be used to track its progress through the assembly line; RFID-tagged pharmaceuticals can be tracked through warehouses; and implanting RFID microchips in livestock and pets allows for positive identification of animals.

Since RFID tags can be attached to cash, clothing, and possessions, or implanted in animals and people, the possibility of reading personally-linked information without consent has raised serious privacy concerns. These concerns resulted in standard specifications development addressing privacy and security issues. ISO/IEC 18000 and ISO/IEC 29167 use on-chip cryptography methods for intractability, tag and reader authentication, and over-the-air privacy. ISO/IEC 20248 specifies a digital signature data structure for RFID and barcodes providing data, source and read method authenticity. This work is done within ISO/IEC JTC 1/SC 31 Automatic identification and data capture techniques. Tags can also be used in shops to expedite checkout, and to prevent theft by customers and employees.

rfid Radio-frequency identificationRFID Tags in bundle

In 2014, the world RFID market was worth US$8.89 billion, up from US$7.77 billion in 2013 and US$6.96 billion in 2012. This figure includes tags, readers, and software/services for RFID cards, labels, fobs, and all other form factors. The market value is expected to rise to US$18.68 billion by 2026.

According to Future Market Insights, the global RFID readers market is expected to witness a significant CAGR of 12.3% from 2017 to 2027. The market was worth US $5,545.5 million in 2017 and; is expected to rise to a valuation of US$ 17,758.8 million by the end of the forecast period.

How Does RFID Work?

RFID belongs to a group of technologies referred to as Automatic Identification and Data Capture (AIDC). AIDC methods automatically identify objects, collect data about them, and enter those data directly into computer systems with little or no human intervention.
RFID methods utilize radio waves to accomplish this. At a simple level, RFID systems consist of three components: an RFID tag or smart label, an RFID reader, and an antenna. RFID tags contain an integrated circuit and an antenna, which are used to transmit data to the RFID reader (also called an interrogator). The reader then converts the radio waves to a more usable form of data. Information collected from the tags is then transferred through a communications interface to a host computer system, where the data can be stored in a database and analyzed at a later time.

Radio-frequency identification Tags and Smart Labels

As stated above, an RFID tag consists of an integrated circuit and an antenna. The tag is also composed of a protective material that holds the pieces together and shields them from various environmental conditions. The protective material depends on the application. For example, employee ID badges containing RFID tags are typically made from durable plastic, and the tag is embedded between the layers of plastic. RFID tags come in a variety of shapes and sizes and are either passive or active. Passive tags are the most widely used, as they are smaller and less expensive to implement. Passive tags must be “powered up” by the RFID reader before they can transmit data. Unlike passive tags, active RFID tags have an on-board power supply (e.g., a battery), thereby enabling them to transmit data at all times.

Smart labels differ from RFID tags in that they incorporate both RFID and barcode technologies. They’re made of an adhesive label embedded with an RFID tag inlay, and they may also feature a barcode and/or other printed information. Smart labels can be encoded and printed on-demand using desktop label printers, whereas programming RFID tags is more time consuming and requires more advanced equipment.

rfid Radio-frequency identification


Types of Radio-frequency identification tags

  • UHF
  • HF
  • LF
  • Glass
  • Plastic
  • Rubber
  • Metal
  • TPE & More

Passive Radio-frequency identification Tags

Passive tags are comprised of three elements: an integrated circuit or chip, an antenna, and a substrate.

The RFID chip stores data and performs specific tasks. Depending on its design, the chip may be read-only (RO), write-once, read-many (WORM), or read-write (RW). Typically, RFID chips carry 96 bits of memory but can range from 2-1000 bits.

Attached to the chip is the antenna, whose purpose is to absorb radio-frequency (RF); waves from the reader’s signal and to send and receive data. Passive RFID tag performance is strongly dependent on the antenna’s size: the larger the antenna, the more energy it can collect and then send back out. Larger antennas, therefore, have higher read ranges (although not as high as those of active tags).

rfid Radio-frequency identification


Active Radio-frequency identification Tags

Like passive RFID tags, active tags have both a microchip and an antenna. The chips, however, are usually larger in size and have greater capabilities than the RFID chips in passive tags.

Active tags have two additional components that differentiate them from passive tags: an on-board power supply and on-board electronics.

The power supply is usually a battery, although it can also be solar. The built-in power supply allows the tag to transmit data to a reader on its own,; without the need to draw power from the reader itself like passive tags do. In addition, active tags can be read from distances of 100 feet or more,; whereas passive tags can only be read from up to about 20 feet

RFID With Arduino

RFID reader can be easily interfaced with the Arduino. There is an RFID module for interfacing with Arduino and there is also a library to make your code simpler.

This RFID module works with SPI Interface, so you need to enable SPI for Arduino in the code itself. The microcontroller and card reader uses SPI for communication (chip supports I2C and UART protocols but not implemented on library) (Maybe someone implements?). The card reader and the tags communicate using a 13.56MHz electromagnetic field.

Library to be used:

  1. RFID.h
  2. SPI.h

rfid Radio-frequency identification


Below I have a sample code that you can download and start using with your Arduino.

Download Sample code by clicking the link below:

RFID is an amazing technology. Go ahead work on it trough some projects and increase your knowledge in this field.

RFID is almost always used in all the IoT projects. So you should go ahead and read about IoT as well.

Hope you like the article. Do comment in the comments section below it really keeps us motivated.

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