Dec 4, 2010

125kHz RFID

RFID stands for Radio Frequency Identification. It doesn't mean to identify the radio frequency but to read a code of identification using Radio Frequency as a link. There are 13.56 MHz, 134.2 kHz and 125kHz type commonly used but could be other frequency also available.
The ID is planted in a card, key chain or a sticker with an inductor antenna works as data link and energy source for the chip. The reader also has antenna for transmitting the energy and read the ID. Therefore it's called a passive type RFID; it doesn't require battery but it must be close enough to the reader. The active RFID can work within longer distance when the battery is still alive.

In my project I used passive 125kHz RFID card or key chain. The output is 10 digit ID transmitted by a serial port with configurable baud rate on setup switches. For example the output is "00005397037". Very handy right? Just put some RFID codes into you microcontroller so some IDs can open a door. Or, receive any code and compare it with employee data for attendance record. Combination with camera is quite reasonable since some "naughty" employees  could duplicate their card and ask someone else to swipe it at the attendance machine.


Anonymous said...

can u give me the code for using rfid in arm7.
my mail id is

Tân said...

Could you share this project? I'm a student and studying about arm7's application! Please email to me:


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