SpudFiles

i built one out of a camera flash circuit. i eventually just gave up and used it to actuate my sprinkler vavle before i modded it, it was pretty cool......

i reccomend a simple camera flash circuit if your making it for a science fair. simply the fact that you can launch a metal marble 20 feet without making a sound is pretty impressive.

if i were you, i would take a pen tube, take some large-guage magnet wire, and make a coil 20 windings long and 15 windings in thickness. make sure you glue it together too......

then take a camera flash circuit (ask a phopo shop, they will give you like 6 disposable cameras for free, wich contain the neccecary components).

rip it out of the camera, and make sure you can charge it up. YAY it works. now solder leads to the capacitor leads, hook it to a switch, wire it to your coil, place a metal ball in the barrel (1/4 inch steel slingshot ammo works great) and flip the switch. next think you will hear is the marble hitting your target if it isnt too far away.

to increase power, add more flash capacitors............

one of the most important things to realize about a coilgun is that the placemnt of the projectile is key. put a nylon screw or something in the back of the barrel and turn it a 1/4 turn every firing untill the power decreases.

have fun. it should be a science fair hit when you soundlessly punch holes in cardboard..........

is the barrel suposed to be plastic or metal? does it matter?

definitely plastic metal will SEVERELY decrease performance becuase it will become magnetized

ive tried to build a coil gun once for a project on school

it didnt shoot, it just rolled a small metal ball forward



you may try to build one, but believe me
its HARD to get it working with power

the reason yours proboably just made the ball roll was because the ball was not placed properly in the coil.

you do realize how important the starting point of the projectile is. literally a 1/2 inch of of the optimum position will shoot it a few inches. but if the optimum starting point is found it could literally be going 30ft with the same setup (trust me its happened and it took forever for me to figure it out)

I bult one that could punch holes in carboard with crossbow bolt tips. They fit perfectly inside of Bic pen tubes. If you get enough cameras, make a bank of like 6 caps wired in series, and fire it with a HV relay. (I made my own) Just be very careful. You really should wear ruber gloves if you go with more than one cap. voltage that high can seriously hurt or kill you.

goto instructables.com and type in coil gun.

Coilguns are a good 'mini' because done right, they can be pretty small. A joint project between me and Ragnarok created a pretty good result for the few quid it cost to do.
Personally, I'd much prefer the coilgun than any other type of mini, just

However, spheres are the worst possible shape for coilgun ammo. If you get 1/4" steel rod, and cut it into inch long slugs, you'll get much better power.

There are entire forums dedicated to such things. You should do a google and take a look.

@hi: A stungun would be useless. The camera flash is only used to charge the capacitors, which is where the real power comes from.

joannaardway wrote:<snip>Ragnarok <snip>

Do you actually call him that in 'real life' or is it an internet thing.....

Michael

joannaardway wrote:I'd much prefer the coilgun than any other type of mini, just

Did you forget to finish that sentence?


I just remembered something I had upstairs.

A capacitor bank with 18 200v PSU capacitors of various farad ratings.
I originally wanted to make a small railgun, but I couldn't find a suitible rail material or a dc pulse switch.

What results could I expect if I made a coilgun with this? I want to know if it's worth it before I buy a bunch of magnet wire.

Do you actually call him that in 'real life' or is it an internet thing.....

If you do, you are awesome.

In their most basic form, these are relatively smal and only need one capacitor, or a bank of small ones.

But i'l probably get stuck into this next weekend, because I'll be using this whole week for a 4000 word report for school: on combustion vs pneumatic spudcannons

I wish I had to do that for school! I could probably write a book on it! I cannot WAIT to go to college!

_Fnord, where did you get your caps from?

i believe he said psu (power supply unit) there in computers, PS2, xbox, some stereos.... well basically anything that converts AC voltage into DC

I meant like from what company/supplier.