Portable Coil Pistol

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[Daniel] had to have runaway in his mind when he built this coil gun. It’s hand held, holds 14 42 gram rounds and can propel them at speeds of 110km/h. Of course when it is battery powered, you have a 90 second warm up time between shots. It can also be used while plugged into a wall socket, which reduces the charge time to roughly 3 seconds. Great job [Daniel].

[via engadget]

57 thoughts on “Portable Coil Pistol

  1. I don’t understand the “warm-up time”. The capacitors are either charged or not. I understand that they can take some time to recharge when connected to a power outlet, but when not ? I fail to see where a regular battery would be located.

    I also second the need of a video or more details. It is so incredibly cool that I begin to suspect that this is only an art project that is not really functionnal. Please prove me wrong, this would make my day !

  2. to iv, capacitors take time to charge. Usually, they charge up “instantly” because their capacitance is relatively small. But if you’ve ever hooked a cap up to a scope with a square wave input, you’ll get a sawtooth output, because of the time it takes to charge and discharge the capacitors. Plus, with most coilguns, you need high voltage, so the battery voltage is probably boosted through cap switching or the like.

  3. Kewl. Anyone know how to find out more? I built one a decade ago but it was lame compared to this beauty! Looks like he’s got fairly high efficiency if he’s recharging in 3 sec and has that sort of muzzle velocity (best I could do was 27ft/sec with 1 Farad of caps).

  4. Okay, anyone else imagined the plasma weapons from Halo recharging when it said it had to charge? Now I want to make that and mod it to look like the plasma pistol.

  5. @overslacked: “And you can tell it’s quality because of the blue LEDs!

    That Had me LMAO..

    This is total sweetness
    [WANT step by step instructions]

    whats with the light bulb?

  6. why does it need the ugly lightbulb in the front? the main shape of the gun could be a bit more sci-fi cool shaped. besides that it’s a great project. wanna build one.

  7. jan: the lightbulb is prolly there to light up when its ready to shoot. at least i hope it is. the idea of putting an eniter light bulb on something, especialy something portable, to indicate something cracks me up.

  8. From the site:

    The bulb is used as charging resistor for the capacitor bank when using the mains connection. the higher wattage, the faster it charges. the problem with charging resistors is that they will dissipate a lot of energy, at this way it is safely dissipated which means less heat inside the gun.
    maybe it’s not the best solution, but it was the easiest.

    the bulb at the picture is 150W

  9. b4n4n4:”The bulb is used as charging resistor for the capacitor bank when using the mains connection. the higher wattage, the faster it charges. the problem with charging resistors is that they will dissipate a lot of energy, at this way it is safely dissipated which means less heat inside the gun.
    maybe it’s not the best solution, but it was the easiest.

    the bulb at the picture is 150W”

  10. @bhaalgom
    have 3 HW and 4 SW hacks and two more articles in engadget and slash dot (and 2 patents and one more pending). I would love to post my url here but I don’t want the spam or being attacked by people who disagree with me in this excellent site. It is not about how many articles we have. you are missing my point. i am a person who believe that we can promote creativity in different ways, but not through weapons and similar types of hacks. This site is watched by kids and I find inappropriate to show gun mods and vibrators (like two weeks ago hack). I am totally in favor of good, creative hacks. Cheers

  11. @sansan: I don’t think where you’ve been posted on the intertubes, if you think science involving weaponry is inappropriate for children you need some perspective.

  12. @silly

    He is free to have an opinion on violence.

    What “perspective” does he need? The kind that sees 7-year old “soldiers” mowing down people with a machine gun in guerrilla warfare?

    Rocketry and ballistics don’t always have to be about guns and explosives you know.

    Personally I would have enjoyed this hack better if it weren’t in gun form. Sadly that seems to be a simple way of carrying and aiming a handheld projectile system.

  13. this thing is awesome! best i’ve seen in a while. even just as a display piece; it kiks ass. check out his site. he clearly put a lot of time and effort into this thing.

  14. The lightbulb makes it look like a joke. Is it there as some kind of resistor? Anyway, very cool this is very interesting technology, which could be applied to other products that are perhaps less deadly.

  15. ellent site. It is not about how many articles we have. you are missing my point. i am a person who believe that we can promote creativity in different ways, but not through weapons and similar types of hacks. This site is watched by kids and I find inappropriate to show gun mods and vibratuld have enjoyed this hack better if it weren’t in gun form. Sadly that seems to be a simple way of carrying and aiming a handheld prwarm-up time”. The capacitors are either charged or not. I understand that they can take some time to recharge when connected to a power outlet, but when not ? I

  16. freakin’ awesome! glad to see these homebrew spaceguns. for the skittish… people have made weapons at home for millenia (such as John Browning, one of the greatest American mechanical engineers), and weapons will likely be a part of human existence forever. at least until we make a weapon *too* good! whoops.

    my only comment/concern is: 42 gram projectiles @ 100FPS or 30m/s isn’t a lot of velocity or energy. is the 42g required because it is the volume and density of ferrous material to get significant magnetic effects? if the projectile could be lightened but efficiency kept the same, muzzle velocity would increase, as well as accuracy, range, and penetration power. 42g, or 648 grains, is about the weight of a .50 BMG bullet! over twice the weight of a 230gr .45 ACP bullet!

  17. Wow. This article is damn cool in two ways to me.

    1. I love the look of that pistol.

    2. I’ve been trying to remember what the name of a movie was for a few weeks now. And wouldn’t you know, it was Runaway :D

  18. too the nuts on here saying guns are bad: this is a feat of engineering. your ten year old can not make one of these and shoot up his school. relax. enjoy it for what it is. nuff said.

  19. Neat, but I’m still looking for someone to build a portable one with ~1000 fps muzzle velocity or at least 350 joules, then things will get interesting.

    IMHO 42 grams is way too heavy, how about something between 10 and 15, 20 tops.

  20. @sidusnare: railguns r shit, not only would u need to carry the ammunition and the batterys like with this coilgun, but also exchange rails because the plasma discharge would wear them out every few shots.

  21. LOL in electronics class we tried to make a coilgun. We had a coil around a hollow plastic tube. Wired it in series with a morse-code-style button for a quick tap of power, then that to a 12 volt power supply. It failed.

    The screw only flew about 1-3 inches, and sometimes went backwards.

    This means we need higher voltage/more jiggawatts, and much better timing.

  22. @ designer: beautiful build. I look forward to finally seeing whatever documentation you have on it (once the deluge ebbs and your site is again accessible)

    @lucas: just a guess (since I haven’t seen the schematic yet), but the light bulb might be a charge indicator (less likely) or being used as a form of variable resistor: originally Wein bridge oscillators used light bulbs in a similar fashion.

    @everyone rabbiting on about guns: first point, know what your kids are doing on the internet. Second, if your child has the technical know-how to build one of these, bravo; if they learn what they need to know to build one, bravo; if they build one of these fairly labor- and parts-intensive projects without you knowing, you have other problems. Third, of all the myriad of things I wouldn’t want a child to see from this site, this is fairly low on my list. This will foster knowledge of projectiles, magnetics, and working within design constraints. Other, still fascinating, hacks on this site (e.g. reprogramming electronic construction signs) have little in the way of educational value to a kid, and are far easier to do. Further, the “gun” is a standard footprint, and portability places interesting design challenges on the system.

    @designer: did you try different projectile weights? It may be that you can get more kinetic energy overall: Given E_k = 0.5*m*v^2, reducing mass to increase velocity gives a better energy trade-off.

  23. One useful addition would be the use of a Krytron along with some Supercaps. Krytrons are easy to get as old copiers from years ago can be found and the krytron can be worth at least one good pulse but a few isn’t uncommon before it needs to be replaced.
    I used to work with Laser power supplies and typically saw a fresh Krytron worth 50 to 100 starts of a 35 watt laser.
    Given a krytron, big caps and a superconducting coil might be fun and dangerous toy.

  24. ive been following rail and coil gun tech for awhile, but havent seen anything new, not like this. apparently its come a long way, if he can get those velocities with that wieght of projectile, and only that amount of power, why the hell isnt he working for the military, theyve been trying to get guns to do that for years, and those all took room sized banks of capacitors

  25. Oh baby baby
    How was I supposed to know
    That something wasn’t right, yeah
    Oh baby baby
    I shouldn’t have let you go
    And now you’re outta sight
    Show me how you want it to be
    Tell me baby cause I nneed to know now
    Just because
    My lonliness
    Is killing me(and I)
    I must confess
    I still believe(still believe)
    When I’m not with you I lose my mind
    Give me a sign
    Hit me baby one more time

  26. Video from site:

    [youtube=http://www.youtube.com/watch?v=In6PM6OtHQc&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&feature=player_embedded&fs=1]

    I think smaller projectiles would help a lot. It would increase the speed of the projectiles, plus you wouldn’t need as large of a charge to move them.

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