Disposable Camera Ignition

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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sputnick
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Fri Jan 23, 2009 10:26 pm

After much delay, I present a sh|tty video of my super camera, it doesn't look very impressive on film, but trust me, it's much louder and brighter in real life. Its also powerful enough to kill me in a split second. If you want to know how to make one, I could try for a DIY post, but it would take a while...

Its inconvenient in terms of time, but trust me, this will ignite even some poorer mixes, since it shoots hot metal sparks everywhere, and it only runs on 1 AA or AAA depending on the camera used...

the exposed spark is very bright, when I wasn't expecting it and was used to unnatural incandescent lights, it gave me flash blindness for a couple seconds and the sound reverberated around the house, making my parents think I was playing with firecrackers

[youtube][/youtube]

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Last edited by sputnick on Fri Jan 23, 2009 11:16 pm, edited 1 time in total.
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Combustion Monkey
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Fri Jan 23, 2009 10:57 pm

I love this, and really want to see you strap it to a huge coaxial combustion. the Coax combustions have ignition issues due to the internal barrel messing with the fuel mixture and cooling of the gasses due to more surface area. If that wont light it nothing will short of a on board fusion power supply!
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rp181
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Fri Jan 23, 2009 11:08 pm

Yay! i get to be the first to say these:
1st off, this has no chance of killing you, unless you attached needles as electrodes and decided to stab your self in the heart with it. On skin, it will only give a small burn and a intese feeling for 10 min.
2nd, if mixes are poor, a more powerful ignition is not going to help. Yes it will burn some, but it will still be horriable. (in fact, some MOT arcs can burn trace flamable gasses in the air)

Also, whats in the big taped up box?
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sputnick
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Fri Jan 23, 2009 11:15 pm

No, It definitely has the power to kill me, 5 capacitors in parallel ramp up the amps more than enough to produce a lethal shock, and it doesn't need to be IN the heart, if I were to touch one electrode with 1 hand, and the other, with the other hand, this WOULD kill me.

as for mixes, Im not saying you can ignite any fuel mix, but it does have an increased chance, since igniting sources are shot around the chamber. and the spark is very hot, the flash is vaporising metal.

I will change it so it doesn't say ANYTHING if you insist, but it is a better spark.
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TurboSuper
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Fri Jan 23, 2009 11:40 pm

Cool! I'm amazed that the photoflash charging circuit doesn't die charging for that long...guess you got a good one.

I've been trying to find a definitive figure on human skin resistance, but I'm seeing all kinds of values. It must be pretty dangerous since you pretty much have the same deal going on inside a computer's PSU.
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sputnick
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Fri Jan 23, 2009 11:45 pm

Well, the circuitry is sound, all the cameras I have used are 100%, and that's easily over 100 of them, they only die when the batterie does, but since they are sealed when you buy them fresh, not many people know that the batteries are changeable, and actually, they are a good source for free batteries, one batterie per camera, and about 100 at a time FOR FREE, its a good deal! just go to a photo developer, and ask for used disposable cameras, they give them out for free.
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rp181
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Sat Jan 24, 2009 10:42 am

Even 10 of those capacitors will not kill you. You are using a camera charing circut, which means wour voltage is limited. More capacitance will NOT kill you. Th voltage has to be high enough to overcome skin resistance (usually around 12kohms) for all that power to be dumped through you. My 5kJ bank would not even kill me,current voltage is 300v. Your bank is probably around 50J maximum. It takes 16 joules through the heart to kill.
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sputnick
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Sat Jan 24, 2009 11:01 am

It's not about the capacitance, the amps are higher because theres more flow of electricity from all of the capacitors, voltage has very little to do with it, for the same reason that tasers dont kill you, despite the very large voltage, and those static shocks you pick up from just rubbing fabric and touching someone are in the hundreds of volts. In short, volts will hurt you, amps will kill you.

When you attach capacitors in parrallel like that, the voltage stays the same, but the amps increase. This is why it is lethal.

some simple refferences here...

http://electrostaticsolutions.blogspot. ... volts.html

check first answer here,
http://answers.yahoo.com/question/index ... 850AAysZ1S

chech second answer here,
http://answers.yahoo.com/question/index ... 819AARZ1S6
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CpTn_lAw
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Sat Jan 24, 2009 11:05 am

Skin resistance varies from one to another, and it depend on too many criteria to be thrown up like that, skin humidity, temperature, thickness etc... We had a test three days ago at the university (currently doing a double license, maths and physics) at the electromagnetics class; my friend who has a skin resistance of approximately 40 kohms felt shocked by a 50V current passing from one hand to the other, The intensity was low, but he felt like a punch in the chest so he says. Voltage is something, see it like a speed; current is another thing, see it like mass. Energy is the combined of these two. Shoot a needles through your heart at 10km/s, you wont feel a thing, put your self in front of a truck running at 10m/s, and tell me if you didn't feel anything....
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sputnick
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Sat Jan 24, 2009 11:11 am

RP181, to respond to your question up there which I missed, there are 5 additional photoflash capacitors hooked up in parallel in the box, They started out just exposed, but then when I saw the first shock it produced, I realised I needed a safer container for them, that's why it takes so long to charge, because it has to fill up 5 capacitors total.
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TurboSuper
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Sat Jan 24, 2009 11:15 am

Just remember that most electronic devices you'll come into contact with are constant voltage sources. A car battery can easily push several hundreds of ams, but you probably wouldn't even feel a tingle from touching the terminals of one. That's because the 12V/(skin resistance) produces a negligible amount of current.

The capacitance only comes into play because a higher capacitance value will discharge slower and thus keep the voltage at a high level for longer. So the question really becomes: Does 200V/(skin resistance) produce enough current to kill you?

Just thought I'd clear that up :roll:
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sputnick
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Sat Jan 24, 2009 11:23 am

Turbosuper, sorry but that makes no sense, you will DEFINITELY feel a shock from a car battery, but there are certainly not "hundreds of amps" happening there.

I will go into this more later when I get back in a couple hours,
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rp181
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Sat Jan 24, 2009 11:33 am

sputnick, your wrong. You wont feel anything from a car battery unless you decide to cut your self. Current kills you, not voltage. This is a spud gun forum, so think about it like that. Voltage is equivalent to pressure, and current is the volume. A small pen tube filled to 400 PSI will do more damage then a marker tube filled with 10PSI.
It takes a combo of voltage and current to kill. The current needs to be high, but it won't matter when the voltage is not suffient to allow that current to pass. Turbo is right.
Taser's do not kill you because they do not source enough current. It has enough voltage, but the high voltage with the low power supply, can only provide so much milliamps. Its simple, look at ohms law. Do you get shocked when you touch a 1.5v battery? Its basic electronics, look it up.
TurboSuper
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Sat Jan 24, 2009 11:53 am

Yeah, people have a good deal of trouble wrapping their heads around this one. When you're a kid you think it's the voltage, then someone tells you it's the current, and you get to look all smart in front of your friends. Then if you go into electronics you come to realize it's a bit of both :P

Tasers are also operating at a high frequency, so I think the "skin effect" might come into play there...not sure. Most of the "litterature"(interweb) only mentions the low current.
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rp181
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Sat Jan 24, 2009 12:24 pm

Tasers have two electrodes that are close together, so path of least resistance. That will help too.
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