Safe
The Safe has a basic setup: GHI Spider board
Power
2x Button
MultiColorLed

The sample:
The led represents the door of the safe. The two buttons allow you for entering a combination (If you have more hardware you could try more difficult combinations).
When the correct combination is entered the door is opened (turning the led green). The door closes again after 5 seconds, unless you press any button which resets the timer.
The created code for which to open the door is cleared after 2 seconds.

This project is based on http://gadgeteerinterfaces.codeplex.com the following parts are used: