Luca Dentella has just published his latest project, an Arduino-based door lock you can open using time-based OTP codes (compliant to the RFC 6238). “The simplest way to generate those codes is the use of Google Authenticator, a free mobile app. I’ve also prepared a simple webpage you can use to configure (scanning a QRCode) the app with the same secret of Arduino…”
For details and Arduino code link visit Luca Dentella’s blog.
Via the contact form.

Amazing, I’m looking for a place where apply this!
Server Room access. I found this looking for a place to buy one. The idea is that you can restrict access to a server room and force people to check in with the NOC. An engineer requires access and can’t get in until they call the NOC and get a 30 second door key access code.