h a l f b a k e r yThe halfway house for at-risk ideas
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I remember being told not to put my finger in a wall socket when I was four or five, because bad things would happen and I could die. |
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Curiosity finally made me do it - but my finger wouldn't fit. I finally managed to get a fingernail in far enough that something happened and my fingertip hurt terribly. |
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I didn't tell anyone, and waited for my untimely early death. When an hour had passed I asked my father what would happen if I put my fingernail in there and received a similar warning. I knew then that adults were not to be relied upon. |
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My nephew, at about age 2, worked out that if
you
pulled a 240V/10Amp plug out slightly and dropped
a
coin down behind it that there was a flash and a
bang and the lights went out, leaving the coin
sliced
into several pieces. He did it several times before
he
got the message from his parents that it was not a
good thing to be doing. |
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He enrolled in an Engineering degree course at the
beginning of the year, aged 18. |
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Mind you, this is the same child who worked out
how to open the clothes dryer and crawl inside it,
before he was 12 months old. |
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From a technical perspective, the problem is that
there's
no way to guarantee that you won't somehow end up
with
the mains current shorted to the wall plate in the
event
of component failure or adverse environmental
conditions. If the neutral and ground wires were
disconnected, for example, it's possible that the least
resistive
path to ground for the house current could be over a
bit of
condensation on the circuit and right through your
body.
Electrical fires have certainly started under more
unusual
circumstances. |
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The only safe way to generate an actual electrical
shock
would be to have the input electrically isolated from
the
output, but I doubt an optoisolator would generate
enough current to shock, and something like a Van de
Graaf generator would be fairly impractical (but very
cool, if you could). A safer way to do it would be to
have
a loud alarm that's triggered by a capacitive sensor,
which could be placed behind an insulator. |
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Or a small capacitor, to deliver a short, harmless jolt. |
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Maybe, if you charged the capacitor with an
optoisolator, and made sure that the entire
"punishment" circuit was electrically isolated from the
mains power circuit. Still, I sort of doubt that an
outlet that /deliberately/ leaks current to an
ungrounded path would be up to code. |
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You might do better to have this built into a multi-
tap adaptor that hugs the wall plate, rather than the
wall plate itself. I don't think I'd feel too comfortable
about putting one in my house, though... |
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I'm not sure this is wise. I have quite good immunity
to infections, high voltages and radiation, and I
attribute all this to my exposures at an early age. |
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5 mA DC seems a little tame. |
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It needs to be a decent jolt to be effective... |
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//I attribute all this to my exposures at an early age.//
There are some good arguments in favour of public nudity but I think you are stretching credulity beyond its design tolerance, Max, if you think it helps develop immunity to infections, high voltages and radiation. |
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What you need is a series of publically funded films expounding the dangers of (for example) throwing your frisbee into an electricity sub-station, playing on the farm, or placing rugs on polished floors. I had nightmares for years about these things, but never once have been fatally electrocuted, drowned in sewerage, or slipped on a "mantrap" positioned rug. |
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I'd like to see a rebuttal to these scare films. |
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"Little Johnny follows all the rules. He never takes
chances, always does what he's told and plays it
safe. Only one problem. Little Johnny is going
to grow up to be... (cue minor chord orchestral
sting) a little pussy. Yes, being a pussy is no treat.
Go for that new career? "Too dangerous." Create
something new and bring it to the market place?
"Somebody might get hurt!" How about just asking
that nice looking girl out on a date? "No chance,
rejection is a real possibility." |
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So go pull that Frisbee out of that electric power
line, jump into that mud puddle of death and
remember, streets are fun to play in and cars have
brakes. So have fun, take some chances and ...
don't be such a pussy."
(Fade in warbling badly recorded happy message
public domain soundtrack music) |
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^ Do what Donny Don't didn't. Sheer genius. |
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If the plate was made from plastic infused with a mesh of 0.1 amp fuse wire, even if there was a short circuit, it would just burn out the fuse wire. |
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Alternatively, and doubling as a prank socket, you could attach a piezo device to the switch (like in a cigarette lighter) which gives you a shock when you flip the switch. |
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It's like a new Sparta - rather than abandoning your children in the wild and bring up the ones that don't fall prey to savage beasts, simply leave your children to roam around industrial/building sites and workshops and keep the ones who retain most of their limbs. |
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May as well get them doing productive work in those places rather than just letting them roam. |
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//If the plate was made from plastic infused with a
mesh of 0.1 amp fuse wire, even if there was a short
circuit, it would just burn out the fuse wire.// |
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It would have to be much less than that. One tenth
of an amp across your heart can be fatal. |
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Given that skin-to-skin resistance is o.t.o.o.
100kOhms, and that mains voltage (240AC; say 350
peak) is on the borderline of being dangerous, that
equates to 30mA. |
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// One tenth of an amp across your heart can be fatal // |
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Do you have any comparable figures for, just as an example, felix domesticus ? |
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Small children, electric shocks ... what's not to like ... ? |
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// leave your children to roam around industrial/building sites and workshops and keep the ones who retain most of their limbs. // |
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"partially derelict" // industrial/building sites and workshops // would work MUCH better. |
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<even more gleeful chuckling> |
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I put keys and paperclips in sockets 5 times as a
child its really a miracle I lived. |
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I too had early childhood adventures with electricity, and
seem to have suffered no ill effect no ill effect ill effect. |
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Sorry, just a little brain twitch. Happens sometimes. No
idea why. |
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// Do you have any comparable figures for, just as
an example, felix domesticus ?
// |
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Actually, cats can endure far more physical punishment,
pound for pound, than humans can. This includes
electrocution; I put in a quick call to my Dad, who says
that a cat could theoretically survive three to five amps
applied directly across the heart. |
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He told me about a cat that was brought to him stone cold
dead after jumping onto a car battery and bridging the
terminals. After confirming that there was no heartbeat
and respiration, he was leaving the room to console the
owners when it picked up its head and started to howl. |
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// leave your children to roam around industrial/building sites and workshops and keep the ones who retain most of their limbs. // |
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//"partially derelict" // industrial/building sites and workshops // would work MUCH better.// |
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Henry VIII only had 6 wives. Imagine if he'd been a
really cool cat. |
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//I put in a quick call to my Dad, who says that a
cat could theoretically survive three to five amps
applied directly across the heart.// |
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That is quite terrifically unlikely. Cat heart
muscle is pretty much the same as human heart
muscle, and would be fried by even an amp
applied for more than an instant. If the cat
bridged a 12V battery with fur-covered skin, it
would probably feel nothing (skin is a pretty good
insulator, and furry skin even more so). |
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If the cat managed to injure itself and get
exposed flesh (or a tongue) on each terminal, it
would get enough of a jolt to make it move pretty
fast, but not much more. |
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This was many years ago, and I didn't get the full story (he
was busy). Could be it gapped the alternator or something.
It's all anecdotal anyway, but the real point is that
housecats will frequently and inexplicably survive things
that will kill a human. |
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Oops. The figures my Dad gave were actually "three to five
tenths of an amp." Something was lost in translation
between my brain and my fingers. |
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// its a miracle I lived // |
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A miracle for you, a tragedy for everyone else
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// exposed flesh (or a tongue) on each
terminal it would get enough of a jolt to
make it move pretty fast, but not much more
// |
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<puts down car battery and jump leads> |
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12.6 km/h from a standing start, based on an
unrepresentative sample of one cat (who is
new to the neighbourhood, and therefore did
not know to flee immediately when we
approached it with a plate of food and a net) |
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//Henry VII only had 6 wives.// |
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I think you have your Henries mixed up, and anyway,
capacitance is measured in Farads, not Henries. |
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However, Edward VII had many wives, all but
one of them belonging to other people
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The nine wives of our fewine fweind, Henwy the 8th
of 7. |
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can a 12V battery really electrocute a cat? I've
bridged battery terminals with a sweaty arm more
than once, I'd describe it as a "nasty tingle". It's hard
to see how a cat's foot could be more conductive,
and the path: up one leg... along body... down
another it longer than my arm. |
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//can a 12V battery really electrocute a cat?// |
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A lot depends on how good you make the
connections. |
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I wondered who was my only customer for mouse-
flavoured super-sharp battery terminals. |
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Have you never heard of "client confidentiality" ? |
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By the way, the sample palladium-plated ones show a significant
performance improvement. For the same power input, the cats are
going an average of 7% faster and 11% further. |
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//Have you never heard of "client confidentiality" ?
// |
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heard of and commoditized, confidentiality is a cost-
option. |
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Damn you and your small print
we'd have
gotten away with it too, if it weren't for you
pesky kids. |
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Bronze confidentiality: we won't actively blackmail
you
Silver: we will hide your details in a locked filing
cabinet
Gold: we will hide your details in the wrong place
in a locked filing cabinet
Platinum: we will actively say it was someone else.
Super Premium Platinum: we will blackmail
someone else, send you a cut of the proceeds and
a complete list of bronze,silver and gold members.
The list could include Platinum members but it's
hard to know. |
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//Electric outlet plates give very mild electric shock
if touched// |
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"No, really, it just gives you a tingle - I remember
doing it when I was like two or three. Here, take
this paperclip." |
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The downside to this is that moms might be a little
reticent to buy something that gives their baby an
electrical shock, no matter how mild. |
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How about just an alarm? That would not only scare
the hell out of them, it would alert the parent that
the little tyke is trying to play shake-hands-with-
Jesus via the electrical outlet. |
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