An RFID reader is a device that is used to interrogate an RFID Tag. The reader has an antenna that emits radio waves; the tag responds by sending back its data.

Radio-frequency identification (RFID) is a technology that uses radio waves to transfer data from an electronic tag, called RFID tag or label, attached to an object, through a reader for the purpose of identifying and tracking the object. Some RFID tags can be read from several meters away and beyond the line of sight of the reader. The application of bulk reading enables an almost-parallel reading of tags.

The tag’s information is stored electronically. The RFID tag includes a small RF transmitter and receiver. An RFID reader transmits an encoded radio signal to interrogate the tag. The tag receives the message and responds with its identification information. Many RFID tags do not use a battery. Instead, the tag uses the radio energy transmitted by the reader as its energy source. The RFID system design includes a method of discriminating several tags that might be within the range of the RFID reader. The different tags with their specifications has been shown in the table below .

Active and Passive RFID

A number of organizations have set standards for RFID, including the International Organisation for Standardization (ISO), the International Electrotechnical Commission (IEC), ASTM International , the DASH7 Alliance and EPCGlobal . There are also several specific industries that have set guidelines. These industries include the Financial Services Technology Consortium (FSTC) which has set a standard for tracking IT Assets with RFID, the Computer Technology Industry Association CompTIA which has set a standard for certifying RFID engineers, and the International Airlines Transport Association IATA which has set tagging guidelines for luggage in airports.

RFID can be used in many applications. A tag can be affixed to any object and used to track and manage inventory, assets, people, etc. For example, it can be affixed to cars, computer equipment, books, mobile phones, etc. The Healthcare industry has used RFID to reduce counting, looking for things and auditing items. Many financial institutions use RFID to track key assets and automate compliance. Also with recent advances in social media RFID is being used to tie the physical world with the virtual world. RFID in Social Media first came to light in 2010 with Facebook’s annual conference.

RFID is a superior and more efficient way of identifying objects than manual system or use of bar code systems that have been in use since the 1970s. Furthermore, passive RFID tags (those without a battery) can be read if passed within close enough proximity to an RFID reader. It is not necessary to “show” the tag to the reader device, as with a bar code. In other words it does not require line of sight to “see” an RFID tag, the tag can be read inside a case, carton, box or other container, and unlike barcodes RFID tags can be read hundreds at a time. Bar codes can only be read one at a time. In 2011, the cost of passive tags started at US$0.05 each and special tags, meant to be mounted on metal or withstand gamma sterilization, can go up to US$5. Active tags for tracking containers, medical assets, or monitoring environmental conditions in data centers all start at US$50 and can go up over US$100 each. Battery Assisted Passive (BAP) tags are in the US$3–10 range and also have sensor capability like temperature and humidity.

Radio frequency identification (RFID) is a generic term that is used to describe a system that transmits the identity (in the form of a unique serial number) of an object or person wirelessly, using radio waves. It’s grouped under the broad category of automatic identification technologies.

RFID is in use all around us. If you have ever chipped your pet with an ID tag, used EZPass through a toll booth, or paid for gas using SpeedPass, you’ve used RFID. In addition, RFID is increasingly used with biometric technologies for security.

Unlike ubiquitous UPC bar-code technology, RFID technology does not require contact or line of sight for communication. RFID data can be read through the human body, clothing and non-metallic materials.

PN532: Along with all the above information i would also like to give you some insight into what RFID/NFC you can use with the Arduino board to test your projects . Since this website teaches you alot about Arduino and stuff , PN532 will suite best for this board . The PN532 is a Reader as well as a Writer . It can be used to write data to the internal transmitter it has and  later transmit the data to the active rfid receiver of same frequency (13.56 Mhz).

PN532 Module
                                                                          PN532 Module
PN532 Board
                                                                            A closer look into the Board


A basic RFID system consists of three components:

  • An antenna or coil
  • A transceiver (with decoder)
  • A transponder (RF tag) electronically programmed with unique information.
Basic Components of RFID System
Basic Components of RFID System

An Active RFID System

  • The antenna emits radio signals to activate the tag and to read and write data to it.
  • The reader emits radio waves in ranges of anywhere from one inch to 100 feet or more, depending upon its power output and the radio frequency used. When an RFID tag passes through the electromagnetic zone, it detects the reader’s activation signal.
  • The reader decodes the data encoded in the tag’s integrated circuit (silicon chip) and the data is passed to the host computer for processing.


The purpose of an RFID system is to enable data to be transmitted by a portable device, called a tag, which is read by an RFID reader and processed according to the needs of a particular application. The data transmitted by the tag may provide identification or location information, or specifics about the product tagged, such as price, color, date of purchase, etc. RFID technology has been used by thousands of companies for a decade or more. . RFID quickly gained attention because of its ability to track moving objects. As the technology is refined, more pervasive – and invasive – uses for RFID tags are in the works.

A typical RFID tag consists of a microchip attached to a radio antenna mounted on a substrate. The chip can store as much as 2 kilobytes of data.

To retrieve the data stored on an RFID tag, you need a reader. A typical reader is a device that has one or more antennas that emit radio waves and receive signals back from the tag. The reader then passes the information in digital form to a computer system.


A radio-frequency identification system involves hardware known as interrogators or readers and tags, also known as labels, as well as RFID software or RFID middleware.

RFID Tags:

RFID tags can be either passive, active or battery assisted passive. Passive RFID does not use a battery , while an active has an on-board battery that always broadcasts or beacons its signal. A battery assisted passive (BAP) has a small battery on board that is activated when in the presence of a RFID reader.

Most RFID tags contain at least two parts: one is an integrated circuit for storing and processing information, modulating and demodulating a radio-frequency (RF) signal, and other specialized functions; the other is an antenna for receiving and transmitting the signal.


Depending on mobility, RFID readers are classified into two different types: fixed RFID and mobile RFID . If the reader reads tags whilst it (the reader) is in a stationary position, it is called fixed RFID. These fixed readers are set up specific interrogation zones and create a “bubble” of RF energy that can be tightly controlled if the physics is well engineered. This allows a highly defined reading area for when tags go in and out of the interrogation zone. On the other hand, if the reader is mobile when it reads tags, it is called mobile RFID. Mobile readers include hand helds, carts and vehicle mounted RFID readers from manufacturers such as Motorola, Intermec, etc.

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