Our final year project is RFID based Attendance cum Security System. This idea came to my mind when I saw our lecturers taking the attendance of 100s of students very hardly. We thought we can integrate the RFID based Security System with attendance system as well. That what our final year project is doing.
BLOCK DIAGRAM OF THE PROJECT:
History of RFID:
In a very interesting article, the San Jose Mercury News tells us about Charles Walton, the man behind the radio frequency identification technology (RFID). Since his first patent about it in 1973, Walton, now 83 years old, collected about $3 million from royalties coming from his patents. Unfortunately for him, his latest patent about RFID expired in the mid-1990s. So he will not make any money from the billions of RFID tags that will appear in the years to come. But he continues to invent and his latest patent about a proximity card with incorporated PIN code protection was granted in June 2004.
What is RFID.
RFID is short for Radio Frequency Identification. Generally a RFID system consists of 2 parts. A Reader, and one or more Transponders, also known as Tags. RFID systems evolved from barcode labels as a means to automatically identify and track products and people. You will be generally familiar with RFID systems as seen in:
• Access Control.
RFID Readers placed at entrances that require a person to pass their proximity card (RF tag) to be "read' before the access can be made.
• Contact less Payment Systems.
RFID tags used to carry payment information. RFIDs are particular suited to electronic Toll collection systems. Tags attached to vehicles, or carried by people transmit payment information to a fixed reader attached to a Toll station. Payments are then routinely deducted from a users account, or information is changed directly on the RFID tag.
• Product Tracking and Inventory Control. RFID systems are commonly used to track and record the movement of ordinary items such as library books, clothes, factory pallets, electrical goods and numerous items.
How do RFIDs work.
Shown below is a typical RFID system. In every RFID system the transponder Tags contain information. This information can be as little as a single binary bit , or be a large array of bits representing such things as an identity code, personal medical information, or literally any type of information that can be stored in digital binary format.
Shown is a RFID transceiver that communicates with a passive Tag. Passive tags have no power source of their own and instead derive power from the incident electromagnetic field. Commonly the heart of each tag is a microchip. When the Tag enters the generated RF field it is able to draw enough power from the field to access its internal memory and transmit its stored information. When the transponder Tag draws power in this way the resultant interaction of the RF fields causes the voltage at the transceiver antenna to drop in value. This effect is utilized by the Tag to communicate its information to the reader. The Tag is able to control the amount of power drawn from the field and by doing so it can modulate the voltage sensed at the Transceiver according to the bit pattern it wishes to transmit.
COMPONENTS OF RFID
A basic RFID system consist of three components:
• An antenna or coil
• A transceiver (with decoder)
• A transponder (RF tag) electronically programmed with unique information
These are described below:
The antenna emits radio signals to activate the tag and read and write data to it. Antennas are the conduits between the tag and the transceiver, which controls the system's data acquisition and communication. Antennas are available in a variety of shapes and sizes;...