A serious challenge

[masonsailor2]

So the wife has ordered the next project, never one to let the machinery sit idle. But this one has a real twist and one I am putting on the forum to all our resident engineers. The piece is a jewelry armoire which will have a main body atop legs with overall height about 48 inches. The wood will be Honduran mahogany with accents in some other undetermined wood. But here is the challenge she has put forth. It will have 27 drawers sized to fit. One for each letter of the alphabet with one extra. She wants a codex type lock for the extra drawer. It will need to involve having to open seven drawers to unlock the 27th. Any other combo of opened or unopened drawers will result in the drawer remaining locked. Oh and no electronics allowed. Where is Leonardo when you need him ?
Paul

[JPG]

7 SIMULTANEOUS OPENINGS(EASIER), OR SEQUENTIALLY ONE AT A TIME(VERY DIFFICULT)

[masonsailor2]

Not sequential. Just seven drawers open.
Paul

[BuckeyeDennis]

Just out of curiosity, why are electronics forbidden?

The first electronic calculators were modeled after mechanical calculators. The transistors were configured to emulate mechanical decade ring counters. Not a very efficient use of expensive silicon, but it's what they knew how to do at the time.

My dad had one of the ultimate mechanical calculators at his convenience store. An Olivetti Divisumma 24. It could add, subtract, multiply, AND divide. Not to mention printing a record of the entire calculation. I loved playing with that thing. A really challenging division problem could make it crank for a good couple of minutes.

[youtube]https://www.youtube.com/watch?v=_kIqG8dndSc[/youtube]

This should be fun!

[JPG]

Not sequential. Just seven drawers open.
Paul

Seven and NONE of the others open?

[BuckeyeDennis]

Does the drawer code need to be configurable, or can it be fixed once and for all?

If the "combination" is fixed, who specifies the magic drawers?

[JPG]

Does the drawer code need to be configurable, or can it be fixed once and for all?

If the "combination" is fixed, who specifies the magic drawers?

Make 7 drawers different from the other 19(the x drawer is also different).

Then the location of the those drawers defines the 'combination' and their location(s) can varied at will.

[algale]

I'd get a new wife.

[JPG]

I'd get a new wife.

That really would be costly!

[BuckeyeDennis]

Does the drawer code need to be configurable, or can it be fixed once and for all?

If the "combination" is fixed, who specifies the magic drawers?

Make 7 drawers different from the other 19(the x drawer is also different).

Then the location of the those drawers defines the 'combination' and their location(s) can varied at will.

Yes. I'm also thinking that it may not simplify anything to restrict the number of OPEN drawers in the combination to be exactly seven (in general). I'm thinking two sets of drawers: the OPEN set and the CLOSED set. The difference in the two could be as simple as the presence or absence of a plug/key. Then we need a big mechanical AND gate for the OPEN set, and a NOR gate for the CLOSED set. Then AND the two output signals to unlock the magic drawer.

So it would be trivial with electronics. Doing it with wood is the interesting part.