Secret knock-detecting mechanical iris project

Over at the Submitterator, BFarn tells of his excellent maker-meld of "Chris Schaie's beautiful Mechanical Iris, Steve Hoefer's Secret Knock detecting Arduino code, and an engraving made with my scratch-built CNC-Router to make the entrance to my garage/workshop/lab a bit more special."

BFarn's project page

Mechanical Iris on the Boing Boing Bazaar