09-06-2012, 05:16 PM
RFID BASED ATTENDANCE CUM SECURITY SYSTEM
INTRODUCTION
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.
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
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.
ANTENNA
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; they can be built into a
door frame to receive tag data from persons or things passing through the door, or mounted on an
interstate tollbooth to monitor traffic passing by on a freeway. The electromagnetic field
produced by an antenna can be constantly present when multiple tags are expected continually. If
constant interrogation is not required, a sensor device can activate the field.
Often the antenna is packaged with the transceiver and decoder to become a reader (a.k.a.
interrogator), which can be configured either as a handheld or a fixed-mount device. 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.
