Bay 12 Games Forum
Finally... => General Discussion => Topic started by: ein on May 04, 2010, 04:56:38 am
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Hey guys, I've been thinking of building a portable coilgun for quite some time now.
I figure that the first step is finding a power source.
So, electrical engineers, I ask you, what would be a good power source?
I've been thinking of lead-acid cells because they can be made at home fairly simply, don't suffer from memory decay, have a decent energy density and voltage, and it fits in a bit more with the steampunk aesthetic I'm aiming for.
I would use lithium ion cells, but those seem like something that I would not be able to make at home, and I don't want to screw around with a laptop battery or something.
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I have but one suggestion: Point away from face... That is all.
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I have but one suggestion: Point away from face... That is all.
Remote Firing Mechanism.
For the prototyping stages, of course.
Easy to build, easy to use.
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I doubt you'll get enough power out of a lead-acid battery, but it'll be worth the try. I'd see if you could get some car batteries and hook them up to a capacitator of some sort. Hopefully they'll discharge quickly enough to load the capacitator up fully.
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If there's a problem with power, it'll more be having an effective battery and capacitors in a compact design.
I'll test the car battery capacitor thing.
I'll probably also reread my stuff on electromagnetics and maybe even start work on schematics.
Honestly, the biggest issue with this project is that I'm fifteen and the person I live with isn't gullible enough to just go buy me copper wire, capacitors, lead plates, etcetera, or even let me go buy it for myself.
Probably because I've been openly talking to a friend of mine about making gunpowder, napalm, and poor man's liquid nitrogen.
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Batteries are a no go. You won't get a high enough current from these. Capacitors are your only option - I hear that you can salvage some from disposable cameras.
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You can also make tasers out of disposable cameras.
But, will a capacitor operate without a main power source (battery)?
'Sfar as I know, the answer is no.
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It's sad, when a young man's scientific interests are stifled by fear and ignorance...
Also: Short circuiting or overcharging lead-acid (or even a lot of types of) batteries can make them explode. Be very careful if you're working with high energies.
Palazzo: I think he wants to use batteries in conjunction with capacitors.
I also don't know what you made before and your experience level, but you might want to start off with something more simple but alike, like a Taser.
Edit: GAH ninja'd :P
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We made these in uni, that was fun. Dont bother with batteries: Worthless. Okay, maybe you could use them to power down some strapped on laser pointer, but eh.
Go straight for capacitors.
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I am WELL aware of the dangers of short-circuiting batteries.
As for experience, I've made a radio, flashlight, disposable camera taser (in science class no less), quite a few computers, and a rudimentary mass driver that was more like a maglev than a coilgun.
I've also worked with bases a lot, and, if I remember correctly, acids are less dangerous than bases.
With non-science stuff, I've done a little bit of metalworking for jewelery and a little bit of carpentry, but I'm no good with manual saws and drills. Power saws and nailguns are the way to go.
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We made these in uni, that was fun. Dont bother with batteries: Worthless. Okay, maybe you could use them to power down some strapped on laser pointer, but eh.
Go straight for capacitors.
Point is that it has to be portable. Capacitors can store enough energy for a shot or 2, but they drain quickly even when they're not being used. Hence the idea to use batteries, who can store more energy, to charge up the capacitors, who can deliver a bigger punch.
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Bingo.
And I need a battery that will charge up the capacitors fast enough to be effective.
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Try reversing the polarity!
(Science-fiction solution FTW!)
OT:
I used to know of a site which went step-by-step in the coilgun making procedure. Too bad Geocities closed (Well, I think it's still a net-gain for the internet.)
When you say portable, Exactly what are we talkin' here. This:http://www.coilgun.info/mark4/home.htm
is portable in the sense you could carry it easily. but needs to be plugged in, at least until the capacitors are charged.
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Get some really high-quality caps and relatively small batteries that just compensate for leakage. Make these into one- or two- shot magazines. That way the weapon itself will have minimal weight and you can easily carry much more power.
Hold on, I'm going to have to draw this out...
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I may be completely missing the point, but are you suggesting the kind of guns in Artemis Fowl that those goblins use, that shoot literal ammo, but also have a separate cartridge of batteries they use at the same time?
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Try reversing the polarity!
On capacitors, that's always a funny... "solution".
For Dwarf Fortress values of "fun". :D
Hey, I've got nothing to add here except I'd like to see the end result :)
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I may be completely missing the point, but are you suggesting the kind of guns in Artemis Fowl that those goblins use, that shoot literal ammo, but also have a separate cartridge of batteries they use at the same time?
A railgun/coilgun works by accelerating a small piece of metal to ridiculous speeds using a strong magnetic field created by electromagnets. Basically it's a normal gun but using electricity in place of gunpowder, also it is much, much, more awesome/destructive. Bigger railguns can launch things at many times the speed of sound.
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I built a coil gun from old disposable cameras that I got for free at Walmart. You just go to the photo development section and ask if they have any used disposable cameras. If they ask any questions, just tell them it's for a science project (possibly for school).
Still have to test it though. In order to provide the juice I'll be using a wallwart to juice up the charging circuits which will in turn charge the capacitors. More circuits = faster charge time. Here's a good resource. (http://www.instructables.com/id/Coilgun-Handgun)
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I know you're probably not looking to copy someone's project directly, but this site (http://www.instructables.com/id/Coilgun-Handgun/) goes into OK detail about building the capacitor bank. If you type 'coil gun' into the search bar, you get a few other tutorials on them too. They also have a section (scroll down on the main page, I think you have to sign up though) for asking questions.
Edit: Oh, ninja'd by xtank.
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Why a coilgun? Its rather inefficient and always gonna be less powerful then conventional black powder, least with anything you can make.
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Because its a COIL GUN.
You are a monster.
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Because its a COIL GUN.
You are a monster.
I subsist on broken dreams.
Also, coil guns are kinda common as a project among basement dwelling mad scientist youths, why not make something more fun? Nuclear reactors are always good, but if you want something more murderous try replicating the shark killing spears the astronauts were given. It was for if they ever reentered and splashed down in shark infested waters. It was basically a spear with a compressed air canister in the handle and a hypodermic needle like stabbing tip. Stab in, release gas, shark has it's stomach turned inside out and shoved out it's mouth. They made a knife version too.
http://www.youtube.com/watch?v=Sa_NC-_fvKs&feature=player_embedded
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Is that where the "We're whalers on the moon, we carry a harpoon" song came from?
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Is that where the "We're whalers on the moon, we carry a harpoon" song came from?
I 'unno
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About that nuclear reactor...
Also, I want to do something with electrical engineering.
Hawaii has this BOE Recognition Diploma that you can get with good grades and a senior project.
The project just has to be something you're interested in, which for me is electrical engineering.
Anyway, I think my science teacher may be willing to let me construct this thing in her room.
I mentioned that I was going to make a lead acid battery and she said I should do it in there.
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About that nuclear reactor...
Also, I want to do something with electrical engineering.
Hawaii has this BOE Recognition Diploma that you can get with good grades and a senior project.
The project just has to be something you're interested in, which for me is electrical engineering.
Anyway, I think my science teacher may be willing to let me construct this thing in her room.
I mentioned that I was going to make a lead acid battery and she said I should do it in there.
Hmm. I'm not sure if coil guns would be legally forbidden in schools or not. Holy shit, MAJOR LOOPHOLE!
My father is an electrical engineer. Maybe next time we talk i can bring up the subject, see what he has to say.
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Hmm. I'm not sure if coil guns would be legally forbidden in schools or not. Holy shit, MAJOR LOOPHOLE!
"It's just an electromagnet setup Mr. Principal. It's not my fault someone stuck a small piece of metal inside, causing it to blast a hole in the gym wall." Yeah, that's real likely to work.
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http://reactor1967.fortunecity.com/
Nothing like building highly dangerous things with plans you found on the internet!
Also, if you want to do electrical engineering, build a death ray.
http://www.youtube.com/watch?v=6-orAgas6K8
http://unitednuclear.com/index.php?main_page=index&cPath=27_82
I've also got plans for a titan nuclear missile.
Hmm. I'm not sure if coil guns would be legally forbidden in schools or not. Holy shit, MAJOR LOOPHOLE!
"It's just an electromagnet setup Mr. Principal. It's not my fault someone stuck a small piece of metal inside, causing it to blast a hole in the gym wall and tear their arm off." Yeah, that's real likely to work.
Fixed
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In addition to practically everyone else, I'm saying use capacitors, and charge them from mains/generator shortly before each shot. If you try making the thing portable by giving it batteries, put simply, you'd be better off weight wise lugging a small genny and some fuel than all the Pb/SO4 batteries to power a moderate sized coilgun.
Honestly though, I'd say you're better off building a railgun instead. You get better performance for less effort and you don't have to worry about stuff like sequentially quenching magnets. Coilguns only really advantage over railguns is that you can basicallyl keep tacking magnets on, and increase the distance over which you accelerate the object. Since you're likely to be shooting BBs or nails, i.e. things that can handle a short sharp acceleration, stick to railguns.
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Hmm. I'm not sure if coil guns would be legally forbidden in schools or not. Holy shit, MAJOR LOOPHOLE!
"It's just an electromagnet setup Mr. Principal. It's not my fault someone stuck a small piece of metal inside, causing it to blast a hole in the gym wall and tear their arm off." Yeah, that's real likely to work.
Fixed
Well I would hope it has a mount of some sort to stop the recoil from killing you. Anyone firing a railgun without that deserves whatever happens to them.
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You are a monster.
I subsist on broken dreams.
I should make that my sig, but I won't.
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You are a monster.
I subsist on broken dreams.
I should make that my sig, but I won't.
I will then.
Anyway, railgun would be better?
What are the pros and cons of railguns versus coilguns?
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CoilGun
Pro:
No rail ablation, even a low power rail gun's rails will wear out if not perfectly sized to the projectile due to arcing.
Easy to make, any solenoid can be used.
Con:
Projectile velocity limited unless you want a complex multi-stage configuration.
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Multi-staging isn't all that tough.
There are lots of ways to pull it off.
Some cheap and dirty, others expensive and efficient.
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Also even a multi-stage coil gun has its max velocity limited due to the time it takes to build up a magnetic field though if your just making it as science project rather than an anti-orbital cannon its probably not a issue.
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I was under the impression that a railgun was at least a two-handed weapon, if not tripod or otherwise mounted, while a coil gun was more of a handgun and/or "BB-gun" weapon.
If that's the case, you can have a pulsed power supply the size of a car to power your Rail Gun, and you can give it two 60-lb. coils pretty easily.
Oh, wait, I'm wrong. The rail gun has a set of brushes and has a powered projectile. I wonder if you could make it a powered Sabot and reuse it.
I'm still optimistic you could orbitally insert a crowbar down Kim Jong Il's windpipe. I'll have to look up how accurate these things are...
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You really want to do something? Make a machine that lets you arc lightning out of your hands like The Emperor.
I think you can do that just by squating on a tesla coil actually.
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If you sit on a tesla coil, the electricity comes out of the highest point.
That's usually your head.
But an arc welder gauntlet would be pretty badass.
I've already made concept drawings for a flamer gauntlet.
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If you sit on a tesla coil, the electricity comes out of the highest point.
That's usually your head.
But an arc welder gauntlet would be pretty badass.
I've already made concept drawings for a flamer gauntlet.
Flamer gauntlet is easy. Any flammable gas product plus pilot light and then just stick it on a glove. Also, couldn't you just raise your hands above your head?
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You could, it just wouldn't be much like force lightning.
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I've heard that here's been work done on a form of lightning gun; basically, it shoots a laser first, which ionizes the air to produce a easy-to-traverse path for the following electro-shock. In other news, I want one soo bad.
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I built a shock device (basically the kind of thing which would be a power source in a tazer) at high school. It consisted of three 9V batteries, in series, a 16V DT relay, though a normally-closed relay would also work, and a button for turning it on and off. It was just wired so that the relay activating would break its own circuit, which would be followed by the collapse of the magnetic field in the coil, discharging a high-voltage low-amp shock through anything connected to both sides of the coil.
My physics teacher of the time recognised the design, and brought out his "spark generator". It was basically the same, but mounted on wood, with a large hand-wound coil and a hand-made switch for the coil to trigger replacing the relay, a lab bench power supply replacing the puny batteries, and a second coil around the first, effectively transforming the collapsing magnetic field to even higher voltages. It produced inch or two long sparks, enough times a second to look continuous...
I bet if we'd proposed it, he'd have helped us build a railgun. Oh well, I'll just have to build one of my own one day.
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You could, it just wouldn't be much like force lightning.
Also, you'd have a few megavolts traveling through your body...
If you really want to make a lightning glove, you'd need to have a sink close to the glove that's charged strongly opposite to the glove's charge. Use spikes on the glove to bring down the voltage needed to ionize the air. When doing tests always stand behind a metallic shield that you do not touch and keep your glove on the opposite side of it. For safety, line the "safe side" of your shield with cork or rubber and insulate it very well. Even then you're doing something that could potentially electrocute you.