h a l f b a k e r yCompound disinterest.
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The Key is a cylinder of non-conductive material with conductive patches on the outside; inside, patches can lead to other patch(es) or simply dead-end. There is no way of telling from just looking at it, what leads where.
Likewise the Lock is a key-shaped hole which also has a non-conducting barrel
with conductive spots; outside the barrel these spots lead to each other. Specific spots can lead to ground or be part of the "on/off", "lock" and "unlock" functions.
Inserting the proper key into the lock wakes up the door-locking mechanism, turning the key to the left lines up different spots which cause the locker to lock; turning the key to the right lines up yet another series of spots to unlock the door. Then the key is turned back to vertical to turn the system off, and removed.
A multiple-position system involving more than the 2 active positions(lock and unlock) may be implemented with different keys made for different access profiles.
The system could also be set up with individually unique keys to log who is accessing it.
A small rechargeable battery can be fitted to the key, either as regular lock power, or as emergency power during a power-outage.
Door-chain maze
http://www.boingboi...doorchain-maze.html
non-powered locking mechanism [jaksplat, May 30 2008]
[link]
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Where does the power come from? |
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You could use the turning of the key to generate power. I think there are safes that work that way. |
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Use an induction coil with a capacitor. Jamb the key in, out, in, out... until the bolt pops. |
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"You could use the turning of the key to generate power."
The way I read the idea, you're turning a round peg in a round hole. I don't think you'll get a lot of work out of that unless you're doing something mechanical as well. Maybe turning the key cranks a magneto? |
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"powered locking mechanism", the power is on the lock side somewhere. |
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Could we get some pros and cons showing how this is superior to existing flat, metal, solid-state keys, keypads, or biometric devices? |
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Seems to me that a fat cylinder of stuff would be harder to manufacture and store than existing keys, and probably less convenient than a thumb print reader... |
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[ye] even easier to not bother putting a lock on the door at all. |
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However I don't imagine making a small lattice of wire, then pouring plastic over it to make a cylinder would be anywhere near as complicated as making the microchips required in your thumbprint reader. |
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Fair enough with the thumbprint reader being harder to make... but I'm still pretty sure that regular keys are easier to make. I'm also pretty sure that as far as carrying keys, a few flat pieces of metal store better than a cylinder, and a properly waxed thumb bears no comparison at all. |
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Of course, if these could be minaturized down far enough, storage might not be an issue after all. But come to think of it, why use a cylinder shape at all? Wouldn't a square, or triangle be just as functional, perhaps more so, as there could be a clearly marked "Lock" and "Unlock" side to slide in? |
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You want to know what makes this idea superior? |
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The fact that you can annotate on it. |
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[ye] hmm.... triangle good I think, though you could make a cylindrical one more complex by having it hit different contact "tumblers" as it turned. Flat keys wear a hole in your pocket though and they're too easy to duplicate :D |
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[normzone]... err... were you not-quite-accusing me of scamming the HB too ? other than that, apologies if I erased yours instead of something like a (corrected) spelling correction |
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Perhaps he's accusing me of something. I've been known to go through off-topic-anno-deleting jags, and major idea editing sprees. If so, my appologies for the impermanence of my opinions. I may have been here for a while, but I'm still feeling out some of the site features and community (Yes Jutta, sorry, but there is a halfbakery community) norms. You can annotate all my ideas if you want, yes, please do! some of my best online aquaintances are well-armed halfbakers named Norm! |
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Or perhaps Norm is simply performing a bit of dry humor. Ah, yes, I can indeed annotate on this idea, but I've annotated on keys before as well. All it takes is the proper tools. Punchawls and engravers work quite well. Knives and dremel tools are a little more hit-and-miss. Although few people annotate in response to the annotations I make on metal keys, so there's a benefit to this idea... but I'm more interested in the benefits such an electronic maze key would have over other locking options, and I'm pretty sure annotating on a cylinder is not much easier than annotating on any other key. |
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Nice door-chain maze, by the way. That might have some practical applications for alzheimer's patients, and others who should remain in the house under care of a more coherent individual... Might... |
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//small battery or AA cell?//
I've left enough leeway for implementation details; but basically a 2-part circuit, half in the cylindrical key section, the other in the lock, if both line up then the circuit(s) is closed. Battery in the key could be a good idea for some applications (or fallback in case the lock power has failed) |
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I suspect the question here is in regards to the size of the cylindrical key. Larger keys could pose a storage issue, while smaller keys could prove more difficult to insert. |
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The cylinder of the key is about the size of a regular cigarette. |
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There's no need for the key to be cylindrical - it can be a flat
blade with connections from side to side or top to bottom.
Insert it one way to open, one way to close. |
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You *could* make it a flat-key, but then the lock would have to be more complicated. One of the "key" features of this system is that the spots on the key line up in different ways to the spots on the lock when the key is turned to a different position. A flat key with this property would mean that the lock would have to have a moving part... much less aesthetic in my opinion. |
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[edit to post] 2 paragraphs added. |
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No, needn't be. Imagine a flat blade. Contacts along the top
edge (1-10) are internally wired to contacts along the bottom
edge (A-J) in an unknown way. Inserting the key connects
contacts in the top of the lock (i - x) to contacts in the
bottom of the lock (alpha to, ah...) and activates the
unlocking mechanism. Inserting the key the other way up
makes a reciprocal set of connections and activates the
locking mechanism. |
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Could work, but that would make it easier to make a copy and preclude having >2 positions (which I think I added to the post and previous anno while you were anno'ing) |
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A single unlock contact is going to be extremely insecure.
It could be overriden by a simple device with the correct
number of contacts, each providing the correct
voltage. You'd be far better off with a
coded response, that is maybe 20 live pins need to be
grounded and 20 unlock pins need to be provided current.
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A similar problem with anything of this sort is that it's
going to be even easier to duplicate than a standard metal
key. Make a device with contacts in all the possible
positions. Set it up so they are programmable to provide
at one what is sensed at another (Voltage at pin 1 can be
set to produce a voltage at pin 35). That's the complex
bit, but as soon as this lock was built they'd be available
on e-bay within a week.
Once you have that device, simply get your hands on the
original key, same way you currently would. Then two
minutes with a continuity tester (<$15 at Home Depot) and
you can program your key to duplicate it. And the tester
and skeleton key can be carried around, no need even to
have a key cutter stashed away some where. A sufficiently
high number of pins, say a thousand, would slow this down
a bit, but then your getting awfully complex on the
structure. |
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[MechE] so you're contending that it's easier to build a device that measures continuity, etc. for a few thousand possible combinations (assuming all the points are on a "grid"), etc. etc. etc.m, than to walk over to the mall with a flat-key and have somebody make a copy ? |
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BTW, you didn't read my post, I don't think.
//A single lock contact...// is another possibly imaginary post. |
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Actually the first bit of your post definitely sounds like
you're talking about a single in contact and a single out
contact, maybe I misread.
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As far as testing continuity for a few thousand (or million
as I read it) combinations, you can do it in minutes with a
continuity tester, not a special device. The number of
possible combinations is factorial, the number of tests is
simply
arithmetic. A ten contact system would require about 15
tests, a hundred contact system require about 1200.
Assuming 2 tests per second (which is probably low), 1200
would take about 10 minutes. It would take a bit longer to
program the device, but not much. While a higher number
of contacts would require more time, as the number of
contacts goes up system reliability goes down, since the
risk of accidental connection between contacts goes up.
Likewise the cost of manufacture goes up significantly. |
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//sounds like you're talking...//
...does, doesn't it. [post edited] not anymore... I musta had a bit of dieseling after I posted. |
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More complicated electronics could be incorporated (resistors, diodes, etc) but I'm trying to keep the paradigm at the plain old electrical continuity level. |
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However I still think it would be more difficult to copy than a standard flat key. For instance you couldn't simply do a wax impression; you'd have to figure out what the insides were like by the method you've stated and that means building a device to do so *and* having possession of the key. Neither of course could the lock be picked by the traditional methods and there a continuity tester comes up short through a simple alarm system (pun intended). |
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