Have you ever wanted to unlock your front door with just your bus pass, a tag, or an old hotel room key? Now you can with the NFC Door Lock, for under $100! It's a super compact Qduino Mini (Arduino-compatible) powered door lock that senses when there is an NFC tag present, unlocks your door using a Servo and multiple 3D printed parts, and makes absolutely no modifications to your current door lock - you can take it apart if needed in a few minutes! This is super useful & I hope to put it on all doors of my house - it's a relatively easy build in a few hours for an advanced user or a great weekend project for beginners!
Find more here: http://www.instructables.com/id/NFC-Door-Lock-with-the-Qduino-Mini-under-100/
It took my Bukito printer about 2 - 3 hours total to print out all of the parts.