Go Down

Topic: Destructive EMP Devices (Read 9104 times) previous topic - next topic

INTP

Doesn't work :(
Don't ask me how I know.
We all know a French baguette would just surrender

calicocat

#91
Sep 15, 2016, 08:41 pm Last Edit: Sep 15, 2016, 08:54 pm by calicocat
 
You'd need something to attract the spark in that direction.
Excuse the vague philosophical style of question, but what actually /is/ an electrical spark then?   I know that with a lighter spark it's really hot bits of flint, but I don't know how I should think of this.  One really interesting thing I noticed with the spark I got from discharging the camera capacitor is that each 'bit' of the spark was travelling in a seemingly perfectly straight line from where it came from, so it was like straight beams of light going in every direction.  I might upload a photo of it later cause it was pretty good!  You say I'd need to attract a spark to make it go in a particular direction...does that mean something is already attracting the spark in all directions? 



I'm not aware of TV or movie prop techs building EMP devices to take out an entire city block...
I thought we were past this.  Why are you still taking what I'm saying out of context?  At the beginning of the thread I was talking about EMPs, but now I'm talking about a little box that goes "vssst" and whether or not you can create sparks safely.  I asked about controlling the direction in regards to that thing about a Pikachu cosplay I said, because if the spark fires in all directions it's going to shock the person wearing the costume and possibly even set fire to them.

I gave you an opportunity to deny it and you admitted you DID want to know so that's where we're at.
This is the only part about my back and forth with you that's actually bothering me.  I'm purposefully not hiding my intentions  because I'm keeping them entirely transparent.  There's nothing I admitted to that I thought was a bad thing, and the "opportunity" you gave me was one I was not remotely interested in.  I know you're going to want to start quoting me and saying stuff like "You said 'XYZ' and you DON'T think think that's a bad thing?  Well sorry but that won't fly for me etc etc", but I'm telling you there's no point because the fact of the matter is you have taken your own interpretation of everything I've said, and you've given your own meaning to it.  That doesn't make you right - it just means it makes sense to you.  I do get where you're coming from in a sense, but at this point you basically won't answer anything I'm asking, even if it's something that would be useful knowledge across all sorts of electronics projects.

 If I asked how I could safely use my Arduino kit to control a much more powerful high voltage circuit as well as the 3V one, you wouldn't even be prepared to tell me what a relay is, would you?  You would withhold any answers to my question based on a literal interpretation you've taken of the hypothetical question I asked, even if that answer was simply telling me what a relay is and what it's used for (even though it's general electronic stuff).  You'd do this all on the principle that I could misuse the information.  What on Earth is the point in that when someone always replies before or after you with a straight answer to my question?! All it means is that you personally cannot be held accountable for anything I do (good or bad) with electronics, or in other words, you prefer not to be involved in what I'm doing.  That's also your prerogative and I'm fine with it, but why then have you replied to me directly more than anyone here?  IT MAKES NO SENSE.   


raschemmel

#92
Sep 15, 2016, 09:06 pm Last Edit: Sep 15, 2016, 11:14 pm by raschemmel
No matter how you slice the cake, if you ask how to do something that can cause chaos or harm, there will be objections.It has to do with we are accountable for what we tell you. If we could tell you how to build weapons tech we wouldn't because then when we read about it in the news (assuming we are not actual victems) then we would feel responsible for helping someone commit the act. I have explained this to you repeatedly in the simplest of terms. If you ask how to build pyrotechnics the answer is the same. Get a pyro-technics license (with the background check) and then you can do whatever you want.

CrossRoads

Read this about vacuum tubes
http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm
To do the same in free air, which makes for a decent insulator, much higher voltages are needed than the 600-700V used in a vacuum tube.
Cars for instance used to have a coil that took the 12V from the battery/alternator (generator?) and created a high voltage which the points & rotor in the distributor cap connected to one spark plug at a time to make a spark across the little gap at end of a spark plug, igniting the pressurized air/gas mixture in the cylinder. https://en.wikipedia.org/wiki/Spark_plug
So 12,000 to 25,000 volts to spark across a little gap - need a lot more to create that same spark and go any kind of meaningful distance. The right kind of footware on a carpet in the winter can generate a pretty good shock too - but only an inch or so, and you being charged up need to discharge into something at a lower charge.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

calicocat

No matter how you slice the cake, if you ask how to do something that can cause chaos or harm, there will be objections.
Okay I get you, but it doesn't stop you giving me general answers to help me understand electronics.  I don't need a pyrotechnics license to ask questions at the end of the day. What about things like plasma balls?  I love stuff like that, but how am I supposed to design my own unless I ask something like "how do I make electricity fly out in all directions and be visible? "

Read this about vacuum tubes
http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm


I'm on it!


Oh, and this was a belter


raschemmel

The Dialectric Strength for air is 3,000,000 V/per meter =>3000 V/ mm

What this means is that two electrodes placed 1 mm apart will arc at 3000V . 
or at 3 million volts if 1 meter apart.
(@ 1 ATM)

Plasma balls are another phenomenon.

westfw

BTW, the "pretty" sparks are little bits of burning metal launched by a momentary high current through a narrow bit of conductor (which is why they're easy to do pyrotechnically - just burn some metal particles!) , possibly with some arcing through the higher-conductivity metal vapor.  Pure electrical sparks (of the 3kV/mm type) are a different thing entirely.
(The Electronic flash is about 350V, and nearly-lethal energy.  Short the cap (carefully) and you get the first type of sparks.  The flash itself is more the second type (but specialized, cause ionized Xenon and stuff.))  Sparks are actually rather complicated things...

raschemmel

#97
Sep 16, 2016, 03:01 am Last Edit: Sep 16, 2016, 03:08 am by raschemmel
FYI, you don't want to know what it is like to see a plasma ball that isn't inside a glass sphere, like the type you would see if excessive current passed through a small metal object , vaporizing some of the metal. This is actually referred to an 'arc flash" and is very dangerous and can result in third degree burns or even death. It is usually associated with electrical accidents but sometimes the result of electrical malfunctions in high voltage equipment. The light from an arc flash is so bright that if you are looking right at it the damage to your eye could be permanent.
I forgot the exact numbers but it was something ridiculous like 10,000 lumens or 1000 times brighter than the sun.

calicocat

(The Electronic flash is about 350V, and nearly-lethal energy.  Short the cap (carefully) and you get the first type of sparks.  The flash itself is more the second type (but specialized, cause ionized Xenon and stuff.))  Sparks are actually rather complicated things...

The person I was with when I did that spark measured 720v before we discharged it.  Me being so new to all of this  thought that sounded like an abnormally high number but he assured me that's what the meter said.  I'm a bit concerned now by that nearly lethal energy part?  For the record he told me the fact...  





Is this your point raschemmel?  Am I out of my depth?  Pardon the pun, but am I playing with fire?  I'll level with you - I'm a pretty impulsive person and tend to run before I can walk when learning things.  I'm actually quite good at that, although it does leave big gaps in my foundation knowledge that I need to fill as I go along.  Because all of the circuits I've been working with are powered by everyday household batteries, I didn't really think there could be copious amounts of danger involved in working with them I was careful.  Nothing else I've ever learned in this way has been particularly dangerous so I guess I'm used to being complacent when skipping ahead or asking those curious questions.   That also goes for the legality of anything I've mentioned (big EMPs were only a hypothetical topic) - I didn't really think anything powered by 2x 1.5v batteries could be illegal, especially if it never left my workstation.  

I have worked in theater tech and live stage lighting/sound before but I've never done pyrotechnics.   I've been looking up the laws in my area, and there's a bit of ambiguity that I'll need to look further into.  It looks like there is a bit of a distinction between stage/theatrical pyrotechnics and fireworks; most of the given laws seem to relate to fireworks, and the licenses also seem to be required by fireworks display personnel.  There's also a point that states you can manufacture explosives without any license in a certain low quantity without storing them if the point is research or experimentation, and also if commissioned by a TV show or for 'cinematic effects'.  I think to properly clarify where I stand, I'd have to know at least what the explosion in the little box that goes vsst is. 



raschemmel

More than likely there is no explosion in that box. The standard procedure is to "fake" the effect with powder ejected by pressure and dub the sound effect. That could  have been magnesium powder ignited by a spark gap and forced out by air pressure and the sound could be dubbed.

As far as whether you are out of your depth, all I can tell you is that there are no careless people working with high voltage and power, because they're dead. There are no second chances. The first careless incident is also the last. I'm over 60 and you won't live to be half my age with your attitude. We have arc flash shields at work that we stand behind during high risk tests.

calicocat

Okay.  Just please don't confuse me with someone like this.  I came across this researching pyro last night and is by far the dumbest thing I've EVER seen.  https://www.youtube.com/watch?v=sByk6ugFJlM

I'm just curious to the point where it could kill the cat, so to speak.  I don't have stupid intentions.

Boardburner2

We all know a French baguette would just surrender
I thought that was the Italians.

Now a frozen pizza on the other hand.....

Boardburner2

The person I was with when I did that spark measured 720v before we discharged it.  Me being so new to all of



Likely a measurement error.

There's also a point that states you can manufacture explosives without any license in a certain low quantity without storing them if the point is research or experimentation,



Sounds like you are in the UK.

The 100 gram rule.

Black powder is a special case , if you make it you have aquired it and an aquire licence is required.
The law was recently changed so that a BP licence can be had as pyrotechnic use is now a valid reason to apply for one.
Other restrictions apply.
Best place to look is the UKPS who were instrumental in having the law changed.

calicocat

Sounds like you are in the UK.

The 100 gram rule.

Black powder is a special case , if you make it you have aquired it and an aquire licence is required.
The law was recently changed so that a BP licence can be had as pyrotechnic use is now a valid reason to apply for one.
Other restrictions apply.
Best place to look is the UKPS who were instrumental in having the law changed.
Correct! Scotland to be specific.


I'm ahead of you there actually.  I have been to UKPS and posted on their forums asking a few questions.  It seems that I'm basically fine to work with things other than black powder though may need an explosives certificate.  However, I don't think at this stage I'll need anything because I've decided just to make automated igniters without any target explosives.  So just some buttons that trigger ematches.  Then maybe I'll try firing some confetti cannons or something.  I don't have any reason to use black powder specifically.  I might get hold of some of the special prime coating used with ematches or try to make my own, but again there shouldn't be any issue as this still just creates a short flame burst for lighting fuses. 


Go Up