[Fabien] ran across a very, very inexpensive RFID visitor on offer extreme a while back as well as with money to burn, added it to his cart. When the USB RFID visitor arrived, he discovered something relatively strange about it (French, Traduction). The RFID visitor presented itself to his computer as a USB HID gadget that spit out characters into a text editor whenever an RFID card was waved above the coil. The only issue was these characters weren’t the hex values recorded on the RFID card. So what’s going on here?
As it turns out (Anglais), this random piece of Chinese electronica sends 10 bytes of data to the computer, just like this well-documented RFID reader. Apparently, both these RFID readers take the hex value of an RFID card, convert those bytes to base 10, as well as pass each digit through a lookup table. Exactly why it does this is anyone’s guess, however because [Fabien] figured out exactly how it worked, he might likewise figure out exactly how to reverse the process.
Unfortunately, the RFID visitor in concern is currently out of stock at offer Extreme. seeing as exactly how many of the electronics offered there are remarkably similar as well as differ only in the name printed on the enclosure, though, we wouldn’t be amazed if a almost identical RFID visitor was offered elsewhere.