RFID kit is cool kit. I will freely admit I'm the type to get excited when I am given a contactless access pass or transport smart card. There's something about the idea of this computer chip wirelessly communicating information, without an internal source of power, that amazes me in a childish way (yes, I do understand the science behind it). Needless to say if it's RFID I'm interested in it.

HID Prox - 125Khz

HID is perhaps the best know player in the RFID access control industry, you'll see their kit on corporate buildings, schools, apartment buildings and everywhere in between. Their 125Khz range of products is perhaps the most well know and dispersed.

Naturally, as it's the sort of thing I love to play with I had to at least make an attempt to deconstruct and understand the process behind this type of RFID technology.

I started out as most anyone does on any project, but Googling to see if anyone else had attempted the same thing. The internet being the treasure trove of knowledge it is, it was not long before I came across some helpful netizens who had invested quite a bit of time playing with HID Prox equipment (links to their site on my link page).

Using their knowledge, and information I was able to obtain freely from many places across the web, I was able to determine exactly what I needed to both read and reproduce these credentials. I was able to read and interpret the card data utilising the following:

To make it into a pretty little unit I purchased a jiffy box and and LCD display, the result is below


Reading was definitely the easy part. As building my own reading hardware was not part of my original plan all I had to do was work out where to purchase a card reader and how to interface with it. A quick visit to eBay and I ended up with both a standard reader and 4 fobs for some testing fun.

HID Prox Key HID Prox Reader

My trusty arduino in hand I set about hooking up the reader to the arduino. With prior knowledge of the 'wiegand format'