My Blog entry:
http://marcuswolschon.blogspot.com/

Blog entry by Ax0n:
http://www.h-i-r.net/2010/01/review-master-1500id-speed-dial-lock.html

pdf explaining the mechanics:
http://toool.nl/Image:The_New_Master_Lock_Combination_Padlock_V2.0.pdf

animation by Michael Huebler:
http://toool.nl/images/e/e1/MhVisualizer_V2.0_p.swf

At Easterhegg last weekend I was introduced to this amazing lock (Master Lock 1500iD).
You can enter a combination of up, left, right and down -movements of ANY LENGTH to be your code.
This mechanism is basically a mechanical hash-function of the movements you do.

This is a simplified demonstration-model to illustrate the code-mechanics.
It contains neither the actual locking nor the reset-mechanism nor the mechanism to set your own combination.

I just finished the design and did not print it yet. But I made sure it is printable.

Print 4 code-discs, one base-plate and one pin-plate.
Put them together as on the image.

You can see the code-discs turn as you slide the upper octaeder around.
Lift the octaeder to see the state of this machine.
Hint: mark one side of each code-weel with a pen.