A gift I made for Maria. Uses mana rocks to unlock a treasure.
All I changed about the box was drilling some holes and painting the mana symbols with gold paint. The lock mechanism is a servo connected to a wood dowel that goes in and out of a screw eye connected to the drawer.
The crystals have EEPROMs with identifiers programmed in. The IC seat on the top of the box connects to the arduino’s I2C bus.
The source code can be found at https://github.com/axlan/magic_box . The only complexity was that I needed to manually change the timer registers to switch between generating the PWM for the servo and the pulsing LEDs.
The altered lands were made at http://mtgcardsmith.com/ by cutting out just the portrait and title and gluing them to normal lands.