coil gun

[3dude_2231]

anyone has experience with building a coil gun?

thought of adding something like this to my mini-bot,
anyway, I need someone to volunteer to be a human target
http://www.youtube.com/watch?v=m86gK-EOEsQ

AWSOMMEEE!!!
FIRTKM - for inspirtion and recognition of techinques (of buildng) killing machines

[lukevanoort]

That coilgun is immensely powerful--not something you want to mess with. Do not expect to build one that shoots steel rods through cans.

I did a bit of research into coilguns last year and built a proof-of-concept gun as a project in my AP Calculus class after we took the AP test, so I may be able to give you some advice. First of all, work with one hand in your pocket and wearing rubber soled shoes. You do not want to be electrocuted by the voltages coilguns operate at, which can be deadly. I can also speak from experiance that 300V, even if it only goes through a finger, is rather painful. (Keep in mind that this is coming from someone who spent many lunch periods toying with a Van de Graff generator that generated potentials of several thousand volts)

The most expensive part of a coilgun will be the switching system (especially if you are doing a multi-coil coilgun) SCRs, IGBTs, and MOSFETs rated at the voltage/current levels you will be using can get a touch pricey. For the actual triggering of the switching circuit, I would use an optical system since it is simpler than some other methods, reliable, and has no moving parts.

The actual coil itself will take some patience to wind as well as a few calculations to determine how best to wind it. The coil also presents another problem, while putting a current through it will generate a magnetic field, the inverse is also true. So, when you cut out the power a current will be generated by the coil opposite to the one you applied to it. This current can damage your electronics (electrolytic caps are especially vulnerable), so you need to put a diode & resistor across the leads from the coil in such a configuration that it doesn't conduct when you apply power to the coil but does when the magnetic field collapses. The magnetic field the coil makes can also wipe data from magnetic data storage mediums, so don't fire one near computers, wallets, floppy disk, and so on.

Another thing, disposable camera flash units are a goldmine for small scale coilguns. They contain electrolytic caps rated at somewhere in the neighborhood of 300V and a transformer circuit that turns 1.5V into around 300V. Often, you can pick up spent camera's from a photo developing place for very little money--twenty-four cameras should supply enough parts and spares for a 3-4 coil coilgun.

ABOVE ALL, BE CAREFUL! A COILGUN CAN KILL YOU, YOUR CAT, YOUR LITTLE BROTHER, AND ANYONE ELSE THAT ACCIDENTALLY TOUCHES IT! NEVER POINT ONE AT ANYTHING THAT YOU DON'T WANT DESTROYED OR DEAD, NEVER LEAVE ONE POWERED UP OR IN A CONDITION WHERE IT CAN BE ACCIDENTALLY POWERED UP, AND ALWAYS TREAT A COILGUN AS IF IT WAS POWERED UP EVEN IF YOU KNOW IT ISN'T!

Happy coilgunning.

[3dude_2231]

thanks for your response,
I'm pretty sure I won't be getting to it =]

but uhh.. maybe some day ^^

[vivek16]

awesome

Ive never seen a coil gun in action before, that was amazing.

-vivek

[Chief Pride]

that was pretty cool, but i dont know if you guys have seen the show on discovery channel called future weapons... really great show, anyway, the gun that can fire a million rounds per second is actually kindof simple... if u made one that just fired one bullet then reload, it just sets the bullet off with a small charge of electricity...

guns are not hard to make, i made a .22 cal pen gun in my metalshop once (yes, it was an 'approved' project)