Audio Lock Box

 

The idea behind this project is to create a seamless and featureless box which can only be opened by tapping a specific rhythm.  A microcontroller processes input coming from an contact microphone and, when the correct series of taps has been registered a solenoid will pull back the spring loaded latch and slightly prop open the lid.  Shortly after the latch will return to its original position so that when the lid is shut the box will once again be locked.

 

 

 

Plan for Completion:

This box will work much as described above save for the locking mechanism which will be a worm drive.  The user will tap a certain combination on the box which will cause the top to open enough for a finger to slip under and open the lid.

The box itself will be constructed of 1/4" aluminum squares, 4x4".  The rough sides will be cut on the waterjet cutter.  The edges will be beveled to 45 to form miter joints between the sides using the Mill and a 45 bit.  The opening mechanism will consist of a small stepper motor with a threaded shaft and a matching threaded hole on the underside of the lid.  When the lid is closed the threaded hole will rest with the weight of the lid on the threaded shaft.  Turning the shaft will force the lid down tight, flush with the four sides.  The threaded hole should be created with a slight taper allowing some room for imprecision.  A microcontroller with microphone input and output to the stepper motor will handle the audio processing and control of the locking mechanism.

Needed Components/Materials:

Remaining Questions:

 

Final Project Results: