Micro railgun

micro railgun

While some railgun projects are attempting to be the biggest and baddest, this one just wants to be functional. It’s not efficient or powerful, but it is really easy to put together. The barrel is constructed from two 3″ long pieces of aluminum weld bar with heavy duty Lucite sandwiched in between. The gap is only 1/16″. A disposable camera charging circuit plus 4 capacitors salvaged from other cameras provide the power supply. The projectile is a tiny piece of aluminum foil. It may not be the greatest gun ever made, but it looks like it would definitely be a good demo unit. Here is a coral cache of the site.

[thanks luke]


  1. spaceout says:

    my cat better be hiding from this one

  2. Jonathan de beir says:

    The pictures doesnt works :(

  3. crash2108 says:

    First to post.

    What would this be useful for?

  4. Jonathan de beir says:

    The pictures doesnt works :(

  5. bill says:

    Link does not work….:(

  6. joe says:

    build a couple of increasing delay one shot TTL’s with 555 (and ample voltage dividing and current protection to get down to ~5 v and small miliamps) in parallel with some sort of small SCR’s and parallel capacitors to get multiple current spikes as the projectile travels down the rails for increased velocity.

    probobly want more parallel charging circuits for shorter downtime.

    I was working on parallel chargers and discharging for multiple flashbulbs in parallel separated by small inductors to excite a 4″ YAG tube.

    higher voltage = shorter burst = more briliant.

    limit of high voltage before flash breakdown and flash… avoid with parallel caps, one polarity leads separated by inductor and flash bulb in parallel. discharge one, immediate potential between ends of inductor and will discharge through tube.

    shorter flash != more excitement.
    xenon flash spectra !~= YAG absorbment spectra
    longer flash better, more photon amp. time, ns/ms timer delays good.

  7. matt walde says:
  8. yurijm says:

    lol, bandwidth exceeded

  9. Stevo says:

    Why is the person who brags about being the first poster never the first poster? It just adds insult to injury regarding their stupidity.

  10. Nick pannuto says:

    stevo, I agree

    Is there a tutorial for this anywhere? I wanna impress my electronics teacher!

  11. grant says:

    God I hate geocities

  12. dirk says:

    this looks like a helluva lot of fun.

  13. weaszel says:

    teh grammer dont works :(

  14. 0xF050 says:

    hmm, a few hours ago when i first saw this link on hack-a-day I of course tried to goto the site, where i got the bandwidth exceeded notice.

  15. tiuk says:

    I can’t believe geocities is still around. All the other popular webhosts that I can remember from the late 90s are long gone.

  16. Adam says:

    After reading that has he concluded saying that he made it but it doesnt have enough power to shot and actaully have some effect? from the website –

    “The Micro-Railgun is capable of firing small graphite slugs, cut from a piece of drafting lead. Granted, they won’t pierce paper, but it’s a start.”

  17. nach0s says:

    the pics arent availabe in the cached version. Does anyone have the pics or a screenshot.

    Geocities is so useless…

  18. Mac says:

    with the seemingly immense bandwidth of hack a day, why doesnt someone make a place to upload hacks from places like geocities so the owners can still enjoy being famous and using their site?

  19. Mikel says:

    So when the OP wants us to harvest capacitors from 3 other cameras, why not simply order the capacitors themselves, wouldn’t that be cheaper?

  20. pretorious says:

    #19, not if you used the film from the disposable, removed it to be developed sepratly, then took the electronics out

    just make sure to wind the wheel for a while after the last exposure, so all the film goes into the canister. then ignore the do not open warnings, and a 35mm cassette is all ready to be developed

  21. ejonesss ejonesss says:

    i emailed the aothor suggesting to upgrade to premium account or if money is tight i could host it free and with unlimited bandwidth from my isp’ user homepage.

  22. TNS says:

    #20, Or you could just get the capacitors for free… Just go into any store that develops film and ask if you can have a few cameras. Once they rip out the film, they just throw the old cameras in a box and I assume recycle them. I once had the kid at Fred Meyer’s offer me every camera in the box…

  23. Jason says:

    If you are interested in building a railgun, go to http://www.4hv.org and search the fourms. That is the best/only group of guys out there that are building them.


  24. luke says:

    i have made the same gun as this a few weeks ago and you get a flash and a spark its fun but if you have the wrong sci staff at school they will think you are a terrorist i didnt even bring it to school and then i had to see the counsler.
    these things are fun to make have a go, it took me less than a day and yess (22) just go to camera shops and just ask for them they are happy to give you as meny as you can carry

  25. dirk says:

    some friends and I are currently working on this thing, we’ve got the capacitor bank up and running, and just need a little more work on the rails to get those going nice and spiffy-like. i did some reading on railguns on my own that I think’s gonna help.

  26. bob says:

    I built this the day I saw the post here. but Alas, I cannot get it to function properly. The projectile does not move. it sparks, and a few sparklets come out both sides, but Its a FAR cry from “a foot long streak of plasma” that the author Describes. It makes me sad.

  27. Jg Physsicsthings says:

    Hey guys. I’ve been getting alot of requests for photos/data of the microrailgun, and I’m
    extremely flattered by the interest in this device, but sadly this project was concluded
    almost two years ago, and what little I did take note of back then has been lost (computer
    failures and replacements). The original prototypes are just gone. Following this project I began (and completed) work on a larger railgun, but even that one has sat unfired for over a year. I just don’t have the time to work on these projects anymore. Considering the interest people seem to have in the microrailgun, I will put together a re-make of this device soon, and take photographs of the process. I’ll let you guys know where it’s hosted on this thread. I’ve recieved numerous, generous offers for bandwidth for this project. I’m sorry I can’t respond to these all individually, but I literally have an inbox full of these emails. Thanks again for the interest. It’s an honor to have been featured on hackaday.com. Luke, congrats on getting it to work, I hope you didn’t get in much trouble at school.

  28. Jacob says:

    I’m one of dirk’s (#25) friends helping with the project. We made a bank of 5 capacitors that came out of disposable cameras and we were unable to get the stream of plasma spoke of in the article. I’ve built a bank of capacitors out of 2200mfd caps found at a local surplus electronics store. 15 total equating to 33 farads. I’ve got the bank wired together and working, just need to get the gun from dirk who is going to be away for the next couple weeks.

  29. jacob says:

    Success! Our initial failure was because we used steel bars as the rails instead of aluminum, and that the size was 1/2″ x 1/2″. Yesterday I checked the site again and the images were there! I was able to find the intended dimensions from one of the images, and built the gun this morning. It works great with 33 farads, let me tell you!

  30. dnv says:

    I’ve been trying to get the images for the site for a while now and i’m not having any luck. Since you said you were able to see the images do you mind checking your cache to see if they are still there and if so could you upload them to a place like http://imageshack.us/ so that others can see them too.


  31. jacob says:

    Dunno why it worked once, but i downloaded the images as quickly as I could because I figured it would be a one-time thing. Here ya go!

  32. dnv says:

    Thanks for uploading the pics.

    I re-compiled the webpage with the images in their original positions to make it easier for people to view it and also for if someone wanted to rehost the page somewhere.

    Here’s a link to a zip file containing the webpage: http://www.mytempdir.com/329172

  33. jacob says:

    Got sick and tired of spending money on batteries so I bought an LM 117 and with a 100 ohm resistor and a 10k pot created a 1.5 volt power supply out of a wall wart i had laying around. I also found an old plastic container and made a nice case for the charging circuit. If anyone’s interested I’ll post images.

  34. Daedalus says:

    Hi, i was searching in google an i find this.
    there are the ignition circuit.


  35. Alex says:

    Hey, I was wondering if someone could create an “idiots guide to making a mini rail gun”? I have the cameras and stuff but I really have no clue what I’m doing ^_^ thanks

  36. brent says:

    i cant wait to make this on the weekend

  37. x says:

    If you don’t know what you’re doing, then you shouldn’t do anything. Those caps are dangerous; just four of them is a bit over 26 joules. You might get an idea of what I’m talking about even if you charge just one cap up to capacity and then short it with an insulated screwdriver. I don’t want to spoil your party, but it’s a bad idea to do things you have no idea about.

    Anyway, if you so insist on endangering yourself… you hook the caps up in parallel and then take one lead from the (-) rail and connect it to the (-) lead of the cap. Then, take a length of wire to use as a switch, connect it to the (+) cap lead, and use something insulated (so your fingers don’t fry) to close it once the caps are charged up. Good luck and don’t hurt yourself or anyone else.

  38. x says:

    if that was a bit confusing (as I know I didn’t actually try to explain) here’s a diagram:

    (+)|/ -|=====|
    (crummy attempt at an ascii switch)

    basically, get your projectile in, charge up the caps, and use something insulated to complete the (+) lead from the cap bank to the (+) rail. Remember, follow the right hand rule; the last thing you need is a ball of hot plasma flying at you.

  39. Adam says:

    Hey, i was wondering if somebody has a detailed step by step instructions for building a small railgun.

    I think i know enough about electricity to build one, But i don’t quite get the construction part.
    for ex. (how long are the welding rods)

    Stuff like that

  40. bgugi says:

    this is a wild idea, but did anyone ever consider clicking the link at the bottom of the page that says “main page,” and then clicking the link that says “micro railgun? *duh* it has photos and everything…

  41. char says:

    could you use tv capacitors instead, or do they not release the energy as fast as flash capacitors?

  42. trinitrogen says:

    I’ve constructed it as best I can from the directions. I got a bunch of Kodak cameras (They wouldn’t give them to me for free so I had to buy them at a whopping 48 cents each). I opened them up and I couldn’t exactly tell which was positve and which was negetive, so being that they were all pretty much were the same “chipset”, I just connected corresponding leads in parallel like the directions. They charge just fine, I can hear it power up and then the light comes on. I’ve got two aligator clips I connected to the ends of of the capacitor bank, but I leave one connected so the otherone is basically my ignition switch when I connect it. I get a little piece of tin foil “no thicker than the rails” (whatever that means. Put it in the middle, and once charged I connect the other aligator clip and…

    I get a big ol’ spark at the aligator clip but Im pretty sure the foil doesn’t move. I think once it vaporized. Anybody have the foggiest whats wrong?

  43. amgroben says:

    Yeah, well I got a bag of salvaged power line capaciters, there a bout 6 incehs in height, by 3″ in diameter….

    they should work fine right? just about 6 of them?

  44. xAVIRZ says:

    the instructions r kinda wacked is it aluminium bars sandwiched inbetween the lucite???????

  45. Xavirz says:

    yo this is boring no1 is answering me and by the way is lucite american/? caus im in aus and i asked the guy at the hardware store and all he said was “fcking americans” and grunted
    ???? help!

  46. R34P3R says:

    I dont think that this is an actual device (at least not from the way you described making it). Aluminum foil is undoubtedly NOT going to be propelled forward by an EMP. It would have to be something along the lines of a steel rod, or rail.

  47. R34P3R says:

    the “railgun” that you describe is not a rail gun, so much as a plasma rifle type item. a rail gun would utilize steel projectiles and launch them with magnetics coils and such.
    however, I feel that this plasma rifle is friggin awesome

  48. Anthony says:

    #46, #47: This is totally a railgun. Your confusion is the misunderstanding of what a rail gun is from the games you have played. It isn’t a railgun because it shoots rails, but rather because it has rails that the projectile moves between under magnetic forces.

    A Coil gun has coils up and down the barrel that pull the projectile along the barrier with magnetic forces.

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