This project was a little different than my usual projects. Instead of having a practical or usable at the end this is simply groundwork for future projects. It could be used in place of the RFID Car Access without any software changes. With a little modification, it could be used to drive a servo to unlock a deadbolt. Deadbolt access would actually be pretty convenient since RFID deadbolts are crazy expensive.
Programming was finished. Schematics were sketched. The video does a pretty good job of explaining how the system works in under two minutes.
Schematic for RFID Authenticator
Anecdotally, when I finished this project I had a huge worry that something was wrong because the green valid light came on unexpectedly. This is not a good thing for a system which is only supposed to turn that light on in very specific situations. It turns out that while shooting the video my left hand got too close to the antenna after scanning the Master tag so it learned my implant by accident. After the video was saved I looked at the stored tags and sure enough, there was the ID for my implant.
published with approval by Brian McEvoy from original blog post at: http://www.24hourengineer.com/2015/07/2015-07-25-sa-rfid-authenticator.html