Sunday, November 2, 2014

StarLink : Attendance System based on RFID

With the passage of time, new technologies are sprouting every day. Our responsibility is how we use it for making our daily life easier. The present era is an era of modern and advanced technology, i.e. Indirectly you can say, it is an era of wireless technology. Wireless phones, wireless devices, Wireless machines, wireless communication....Almost everything is wireless. The revolution in wireless technology eases and comforts our daily life.


Now, when it comes to recent technology, Star Link India is always front of the race in using recent trends in its devices. So, today we are going to discuss the method of marking attendance. This can be done by showing a simple card and that card is known as RFID card.

What is RFID?

RFID stands for Radio Frequency Identification. It is a generic term used for technology that uses radio waves to automatically (contact less) identify people or objects. This card contains microchip connected to an antenna. The microchip usually stores the data or generally it contains Unique serial number (UID), whereas antenna convert electromagnetic waves to electrical power/signal and receive waves from the reader.
The chip with antenna together is called RFID transponder or RFID tag.

How RFID works?

An RFID system consists of a tag, which is made up of a microchip with an antenna, and an interrogator or reader with an antenna. The reader sends out electromagnetic waves. The tag antenna is tuned to receive these waves. A passive RFID tag draws power from field created by the reader and uses it to power the microchip’s circuits. The chip then modulates the same waves using ASK (Amplitude Shift Keying) and reader demodulate signals and convert to digital data and in response reader modulates the same wave and tag demodulates. So in this way half duplex communication takes place on the same wave.


Types of RFID

There are basically two types of Tags or RFIDs – Read-only and Read-Write.
Read-only microchips have information stored on them during the manufacturing process. The information on such chips can never been changed.
Read-write tags usually have a serial number (UID) that can't be written over. Additional blocks of data can be used to store additional information about the items the tag is attached to.

How secure it is?

Whenever we use any technology, the security is the major concern that should be kept in mind. So in RFID a cryptography engine is used that prevents from illegal reading of information. Challenge Response Authentication is commonly used to foil repeated transfer of messages between tag and readers, preventing repeated transmission.
For reliability, CRC (Cyclic Redundancy Check) is used.

Standards and Protocols for RFID

Depending on the use and applications, a number of organizations have set a different parameters and protocols. These organizations include ISO, IEC, ASTM International, DASH7 alliance and EPC global.

Out of numerous protocols and standards we use ISO/IEC 14443. This standard is a popular HF (13.56 MHz) standard for HF RFID which is being used as the basis of RFID-enabled passports under ICAO 9303. The Near Field Communication standard that lets mobile devices act as RFID readers/transponders is also based on ISO/IEC 14443.

Frequency of RFIDs

Depending on the application, three major frequency ranges for RFIDs are there. They are Low frequency, High Frequency (HF) and Ultra High Frequency (UHF).

LF are in the range of 125-200 KHz, HF-13.56 MHz and UHF - 850-900 MHZ.
But in our application of Attendance System and Access Control, we use LFIDs and HFIDs.

Now let us discuss, how we use this RFID tag and incorporate with our technology. Basically the information of the employee like the fingerprint template or other information are written in it. After that, any employee can use this card as his identity, only he has to show this to the device installed.
This method is very effective and efficient in the companies with larger employee strength. Helps the Management to save a lot of time and money as well.


 

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