Wiegand Readers

[rbright]

Has anyone tried interfacing a picaxe to a Wiegand reader that are typically used for access control.
Cheers

 

[hippy]

No.

However I did look up the Wiegand protocol and that seems to be a simple four wire interface, 0V, +5V (check), DATA0 and DATA1. The DATA0 and DATA1 are open-collector (check) and one or the other will go active low to indicate a "0" or "1" data bit. There are 26 ( or more ) pulses on DATA0 or DATA1 and a rate of around 500 pulses per second (check).

500 pulses a second is 2mS between pulses which the PICAXE should be able to manage. Wait for a 0 or 1 bit, accumulate those bits, check the parity, respond to the data packet.

' Assumd DATA0 and DATA1 conenct to Input Pins 0 and 1
Do
  Loop b0 = pins
  If bit0 = 0 Then
    Gosub Add0Bit
  Else
    If bit1 = 0 Then
      Gosub Add1Bit
    End If
  End If
Loop

 

[hax]

If you are after a quick solution, you should look at the ID12 and the ID20 RFID readers which have a serial output which is very picaxe friendly.

http://www.sparkfun.com/commerce/product_info.php?products_id=8628

Or a magnetic card reader:

http://www.sparkfun.com/commerce/product_info.php?products_id=8633

 

[Landondesi]

Has this ever gone anywhere ?? I have built a circuit to do so and am currently working on getting the timing correct in order to read the data sent from the reader. My interrupt procedure works great but need help with the timing. I have a standard 26-bit wiegand reader and have not been able to get a singel shred of data from it, however it always trips the interrupt just fine.