johng@trwind.ind.TRW.COM (John Greene) (03/04/88)
I was talking to a few people the other day about the strange things that
past science teachers did. Of the the subjects was a 'shock box' that was
metal on two sides and had DO NOT TOUCH written all over it. Naturally
someone would want to know what the big deal is and pick it up receiving a
harmless yet eye-opening zap.
Then I thought of a perfect application for such a device and decided to build
one. I know there are several ways to step up the voltage to a shocking level
but I am getting concerned that I may go too far and create levels that may be
potentially harmful. Thus, my reason for posting to the net.
Has anyone seen or built similar devices in the past? I would like to hear
about the various ways to generate and trigger such a device. The smaller the
better. Automobile coils are out of the question. Please respond by Email if
you don't want to post to the net.
Thanks in advance.
--
John E. Greene "People are just like frankfurters....You have to decide
if you're going to be a hot dog or just another wiener" DLR
TRW Information Networks Division 23800 Hawthorne Blvd, Torrance CA 90505
ARPA: johng@trwind.TRW.COM USENET: ..trwrb!trwind!johngdale@amc-vlsi.UUCP (Dale Wlasitz) (03/08/88)
The following device is quite harmless and produces the required effect. Purchase a power cube from E.R.G. (Endicott Research Group) or equivalent. The cube must be for 12 volt D.C. input and 180 VAC output. These cubes are typically used for powering the luminescent panels for back-lit LCD's. If you power them from a 9 Volt transistor radio battery they product ~150VAC unloaded. Since the output is very low current there is little danger of serious shock potential. To enable the system use a micro-switch to make contact as required....we fit the entire unit inside a coke can, when lifted the fine wires taped to the exterior of the can produced a nice tingle to the unsuspecting. The best is to drain the can and open the bottom without disturbing the top........then leave it in the fridge. It is cheap to produce....one battery....one cube....and you even get to drink the cola. Have a laugh....Dale disclaimer: I didn't see who did it.......honest.
rona@videovax.Tek.COM (Ronald K. Anderson) (03/08/88)
In article <307@trwind.ind.TRW.COM> johng@trwind.UUCP (John Greene) writes: > >I was talking to a few people the other day about the strange things that >past science teachers did. Of the the subjects was a 'shock box' that was >metal on two sides and had DO NOT TOUCH written all over it. Naturally >someone would want to know what the big deal is and pick it up receiving a >harmless yet eye-opening zap. > >Has anyone seen or built similar devices in the past? I would like to hear >about the various ways to generate and trigger such a device. The smaller the >better. Automobile coils are out of the question. >-- >John E. Greene My cousins used one on me back in '67. The front and back covers were made out of foil with some kind of pattern printed on them to make it look like an innocent book. on the inside front cover was some sort of metal plate that a magnet on the end of a metal "spring" stuck to. When you opened the book far enough to see what was inside, the tension on the spring ( actually a resilient metal bar ) overcame the magnet's attraction force to the metal plate, and the bar would bounce off a microswitch several times before damping out. The microswitch would complete a circuit in the primary of a small step up transformer. The voltage impulses induced in the secondary was coupled to the foil covers, and the victem's hands ( arms and chest ) completed the circuit. Although the current produced by a small battery and your average transformer would probably not harm your average HEALTHY person, common sense would dictate which friends ( enemies, cousins or ? ) to victemize. At the time, I didn't think it was very funny, but I did admire the cleverness of the design. It might even have played a small part in inspiring me to pursue a career in electronics. My employer takes no responsibilty for this. R.K.Anderson-Gibson-Kappel-Heist-Wood-Galbreath-Olson-Heinz ----------------------------------------------------------------------------- new: rona@videovax.tv.Tek.com old: {decvax | hplabs | ihnp4 | uw-beaver | cae780}!tektronix!videovax!rona
markz@ssc.UUCP (Markz Zenier) (03/08/88)
Go to your local joke and puzzle store for the shock boxes, They are a buzzer, induction coil setup with a switch usually in the form of a book, with foil covers. You can buy plastic vomit while you are at it ;-)
todd@uop.edu (Dr. Nethack) (03/09/88)
In article <4881@videovax.Tek.COM>, rona@videovax.Tek.COM (Ronald K. Anderson) writes: > In article <307@trwind.ind.TRW.COM> johng@trwind.UUCP (John Greene) writes: > >I was talking to a few people the other day about the strange things that > >past science teachers did. > would probably not harm your average HEALTHY person, common sense would dictate I, er, beg to differ... the "Nova" stun gun runs on a 9v. battery, and it can KICK YOUR BUTT!! You may wish to be careful about how you build your circuit. And don't hit on heart patients, or guys with pacemakers. (use your radar counter-assault devices for that) ;-) ----------------------------------------------------------------------- + uop!todd@uunet.uu.net + + cogent!uop!todd@lll-winken.arpa + + {backbone}!ucbvax!ucdavis!uop!todd + -----------------------------------------------------------------------
wolfgang@mgm.mit.edu (Wolfgang Rupprecht) (03/10/88)
I wasn't going to post any shock-box articles. They're certainly fun to joke and think about, but I have real reservations about their safety. Back 16 years ago (when I was 1/2 of this age, damn!) I built a very simple relaxation oscilator, dc to dc step up box. It used a 45v photo-flash battery, an rc filter, and an scr with a 40 volt diac triggering it. The transformer was a 2" xenon tube ignition transformer which put out ~2kv. I rectified the output of this with a few series 1kv diodes, and stored the charge on a few 0.1 ufd caps, chosen for their low leakage. The intention was to have a very high efficiency device, the size of a pack of cigarettes, that could run for *many* hours. As a shock-box this was a great success. Anyone that got shocked was the greatest evangelist for finding the next sucker to receive a jolt. The box always drew quite a crowd of spectators. Although the box only packed a small charge, Joules = 1/2 Capacitance * (Volts ** 2) (* 0.5 0.5e-6 2e3 2e3) 1.0 joule four people (out of tens shocked) asked me days later, if I thought it was possible that the box to cause back pain. I thought nothing of it at first. Then it dawned on me that each of these four people had received jolts from on hand to another. Hmm. That got me worried. I'm just glad that nobody had a weak heart. Nothing like someone keeling over to turn the tables on the joke... Wolfgang Rupprecht ARPA: wolfgang@mgm.mit.edu (IP 18.82.0.114) 326 Commonwealth Ave. UUCP: mit-eddie!mgm.mit.edu!wolfgang Boston, Ma. 02115 TEL: (617) 267-4365
jshelton@deimos.ads.com (John L. Shelton) (03/10/88)
Two things are required to inflict damage on a human via electric shock: 1. Voltage. Low enough voltage will not cause damage (at least DC). That's one reason it's safe to work with 12v car electricity. 2. Current. It takes a certain amount of current (I believe 75 ma, but don't rely on this) to stop a heart. Safety-related devices, such as ground fault interruptors, are designed to trip at much lower levels, such as 15ma. If you must build a shock box, make it current-limited to prevent trouble. =John=
dbraun@cadev4.intel.com (Doug Braun ~) (03/11/88)
In article <439@amc-vlsi.UUCP> dale@amc-vlsi.UUCP (Dale Wlasitz) writes: >We fit the entire unit inside a coke can, when lifted the >fine wires taped to the exterior of the can produced a nice tingle to >the unsuspecting. Am I correct in assuming you used a JOLT Cola can? (All the sugar, twice the Caffeine, and 180 times the EMF!) Doug Braun Intel Corp CAD 408 765-4279 / decwrl \ | hplabs | -| oliveb |- !intelca!mipos3!cadev4!dbraun | amd | \ qantel /
phd@SPEECH1.CS.CMU.EDU (Paul Dietz) (03/11/88)
In article <2945@zodiac.UUCP> jshelton@ads.com (John L. Shelton) gives some
overly optimistic values...
From "The Current that Kills" in October '87 IEEE Potentials
1 - 3 mA Mild Sensation
3 - ~10 mA Painful Sensation
~10 - 30 mA Cannot let go. Current may increase to fatal level.
30 - ~75 mA Breathing stops, often fatal.
~75 - ~250 mA Heart fibrillation in 1.4 seconds, usually fatal.
~250 mA - 4 A Heart stops during shock, may restart if current removed
before death occurs.
4 - 10A Severe burns, not fatal unless vital organs burned.
This table is a rough guide, and I only post it as a warning to people
not to mess around with this stuff unless they really know what they
are doing.
Some more stuff from the article:
Women seem to have even less tolerance than men; on average, 2/3 the voltage
will cause problems.
Let go currents for women can be as small as 6mA. Thus, ground fault
interupters are usually set around 5mA.
Just wanted to clear the air a bit on this one...
Paul H. Dietz ____ ____
Dept. of Electrical and Computer Engineering / oo \ <_<\\\
Carnegie Mellon University /| \/ |\ \\ \\
-------------------------------------------- | | ( ) | | | ||\\
"If God had meant for penguins to fly, -->--<-- / / |\\\ /
he would have given them wings." _________^__^_________/ / / \\\\-taro@uhccux.UUCP (Taro Nobusawa) (03/11/88)
In article <2945@zodiac.UUCP> jshelton@ads.com (John L. Shelton) writes: >Two things are required to inflict damage on a human via >electric shock: >1. Voltage. Low enough voltage will not cause damage (at least DC). >2. Current. It takes a certain amount of current (I believe 75 ma, >but don't rely on this) to stop a heart. Safety-related devices, BTW, isn't 60Hz supposed to be a bad frequency to use? ___ |N| -- "Mad as a hen wetter...goodbye and good day. THPPT" -Opus Taro Nobusawa taro@uhccux.uhcc.hawaii.edu taro@uhccux.BITNET Compu$erve 71071,322 {ihnp4,uunet,ucbvax}!ucsd!nosc!uhccux!taro
jeffw@midas.TEK.COM (Jeff Winslow) (03/11/88)
In article <3616@bloom-beacon.MIT.EDU> wolfgang@mgm.mit.edu (Wolfgang Rupprecht) writes: >Although the box only packed a small charge, > > Joules = 1/2 Capacitance * (Volts ** 2) > (* 0.5 0.5e-6 2e3 2e3) > 1.0 joule > >four people (out of tens shocked) asked me days later, if I thought it >was possible that the box to cause back pain. I thought nothing of it >at first. Then it dawned on me that each of these four people had >received jolts from on hand to another. Hmm. That got me worried. There may be a good reason for it. In pawing through UL1244, which is the U.L. standard for safety of test and measurement equipment, I found a definition of electric shock danger (which the equipment being certified may not have) which includes the following points of interest: If the voltage between two accessible parts is between 450v and 15kv, the product of the capacitance between the two parts and the voltage may not exceed 45uC. In your case it was 1mC - over 20 times that! For higher voltages they set a limit of 350mJ of available energy. 1 joule may be more than you think. The difference between the threshold of feeling and the threshold of fatality for current flowing through your body is less than a factor of 20. UL shock standards are generally set at a somewhat conservative threshold of feeling. Anyone who messes around with this stuff - please be careful. Jeff Winslow
gwu@clyde.ATT.COM (George Wu) (03/11/88)
In article <2945@zodiac.UUCP> jshelton@ads.com (John L. Shelton) writes: >Two things are required to inflict damage on a human via >electric shock: > >1. Voltage. Low enough voltage will not cause damage (at least DC). >2. Current. It takes a certain amount of current (I believe 75 ma, >but don't rely on this) to stop a heart. > >=John= It's not the voltage that causes your heart to stop, but the current. Naturally, voltage and current are related, but it's the current that really matters. I've always been told current as low as 20 mA can be dangerous. I wouldn't be suprised if even lower currents interfered with the functioning of a pacemaker. A high school physics teacher of mine used to zap kids who fell asleep with a pretty good charge, until some parent threatened to sue him and the school. I don't know what current was involved, and kids tend to be pretty healthy, but I've always thought was lucky. -- George J Wu UUCP: {ihnp4,ulysses,cbosgd,allegra}!clyde!gwu ARPA: gwu%clyde.att.com@rutgers.edu or gwu@faraday.ece.cmu.edu
jws@hpcljws.HP.COM (John Stafford) (03/11/88)
I wouldn't quite claim it is safe to work at automobile voltage (12V) levels. The second factor, current, comes into play here; cars may only be 12 volts, but there are (especially when starting) quite a few amps around. Kids, don't try this at home. Actually I believe the most dangerous currents are within a particular range (which I don't remember). Below that range there is little danger, above the range is bad, but can actually be less likely to be fatal (if removed reasonably promptly) than currents within the range. Within the range, the current causes fibrillation (spelling?), above the range it tends to cause the heart to stay in one state (contracted I believe). Apparently it is easier to restart the contracted heart than a fibrillating one. Keep one hand in your pocket...
flaig@cit-vlsi.Caltech.Edu (Charles M. Flaig) (03/12/88)
In article <1091@PT.CS.CMU.EDU> phd@SPEECH1.CS.CMU.EDU (Paul Dietz) writes: >From "The Current that Kills" in October '87 IEEE Potentials > >1 - 3 mA Mild Sensation >3 - ~10 mA Painful Sensation >~10 - 30 mA Cannot let go. Current may increase to fatal level. >30 - ~75 mA Breathing stops, often fatal. >~75 - ~250 mA Heart fibrillation in 1.4 seconds, usually fatal. >~250 mA - 4 A Heart stops during shock, may restart if current removed > before death occurs. >4 - 10A Severe burns, not fatal unless vital organs burned. Since most shock box circuits only deliver a single short pulse, I would interpret this table to mean that shock boxes delivering 250mA are safe. And possibly up to 4 A depending on how reliably a heart restarts after a current pulse (after all, this is something they use to restart hearts in an emergency). I remember a time in my foolish youth when I was playing with carbon arc lamps using salt-water rheostats to limit the current. At one point I was using a transformer to step the line voltage up to several hundred volts for easier arc ignition. Naturally a time came when my hands were damp with salt water, and I was holding onto a conductor on one side of the arc lamp and touched my other hand to the other side to adjust the spacing. I've never been kicked in the chest by a mule before, but I think I learned what that description refers to! Luckily having all of my muscles convulse also threw me and my chair over backward and broke the connection, but I was shaky for the rest of the evening. Needless to say, I have been MUCH more careful ever since. Maybe I will live to a ripe old age after all. Be VERY careful when you play around with high voltages, or when you play with relatively low voltages which make very good contact (such as with wet skin). Either one can produce the current which can kill you. ______________________________________________________________________________ ___ , , ,;,;;;, / Y /| /| Charles Flaig ;/@-@\; | |/ __, ,__ |/ flaig@csvax.caltech.edu | ^ | | /^\ / | | | / /\ /\ \=/ \____/| \_/|_/\_/ \_/ \_\/_/_/_/ "What, you think they PAY me for this?"
ron@topaz.rutgers.edu (Ron Natalie) (03/16/88)
Gee, I always thought it was the ENERGY that mattered in cardiac electrical shock. That's why my Defibrillator/Cardioversion unit is callibrated in Joules. -Ron