Need help RFID issues

Washer Medic

Hi I currently have a commercial access control system that use HID key fobs (wiegan 32 bit system @125kHz I believe but have not bin able to confirm) I would like to build a project that Would use the existing fobs with a bs2·(will describe project on another post). I ordered the RFID reader from Parallax but it will not read my existing fobs is their a way to modify the Parallax reader to do this or is their a way use a commercial HID reader with a basic stamp
FYI
My experience with electronics is novice
I have the BS2 discovery kit also the industrial control and applied sensors but have not had much time to work with them yet
Thank You
Brian

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There's nothing a good wack with a hammer won't fix

Darn I let the white smoke out again

Jon Williams

The Parallax RFID reader is designed for a specific tag: the EM Microelectronics-Marin SA EM410 passive tag, which is what we sell (two versions). It cannot be modified to read other tags.

If your commercial reader has a serial or other BASIC Stamp compatible output then you could probably use it; you'll need to get the specs on your commercial reader to determine that.

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Jon Williams
Applications Engineer, Parallax

Washer Medic

Hi Jon thanks for your reply
I have bin researching (Google and local venders) commercial rfid readers and found the attached files
Question if the commercial reader uses 2 data lines one for 0 and 1 for ones does this make it parallel?
How could I integrate this with the bs2?
Can anyone explain how this works?
Brian

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There's nothing a good wack with a hammer won't fix

Darn I let the white smoke out again

Oliver H. Bailey

All low frequency RFID are serial by nature. It's essentially a charge pump that responds to a specific oscillation frequency. Not much different than a cap driven oscillator for a microcontroller. If you want to understand how RFID works I reccomend going to the Microchip web site and downloading their documents on how the rfPIC works. They use to have some excellent reference designs. If your a novice you have your work cut out for you. RFID is not terribly complicated but if your trying to understand electronics and RFID it may take some intellectual digestation to fully comprehend how it all fits together. My next embedded book is on embedded wireless and cover RFID. It won't be out until next year.

Oliver H. Bailey

Washer Medic

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Hi all
I’m still studying commercial RFID readers could any one explain how I could input the 2 data lines from the reader to the stamp I think I understand one line but with 2 I don’t have a clue iv included the following text from my research if that would help
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26-bit Wiegand format consists of a parity bit, 8-bit facility code, 16-bit user ID, and parity bit, for a total of 26 (1+8+16+1=26) bits
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The wiegand signaling standard utilizes two data lines to carry card data to the controller. They are named data1 and data0. As the names impart, the data1 line carries the "1" bits of the data stream to the controller, and the data0 line carries the "0" bits. The picture below is a graphical representation of a wiegand data stream for the binary value "01101". Each dip in the line represents a change from 5V to 0V, thus communicating the bit.
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Figure 1. Sample wiegand data stream
Thank you Brian
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There's nothing a good wack with a hammer won't fix

Darn I let the white smoke out again