Heya, nice project. My friend made a railgun for his final project at school. It didn’t shoot though, anyway, I was wandering how do you know if the caps are charged?

Thanks for the comment Axim,

When the caps are charging they make a high pitched buzzing sound, when they are charged this sound dies down. Also I timed how long it took to charge using a stop watch and my multi meter, so I can approximate how long it’s going to take using that time.

Wicked! I’d really like to see a picture of the can after it was shot, though…

that is pretty awesome there. what’s the range on the projectile, and, can it break skin?
not that i plan on using this as a weapon or anything, just curious…

What kind of current is coming out of the ten capacitors in parallel?

Sweet. Im going to build one right now. What gauge magnet wire did you use?

ok now think about it from a physics perspective. and newtons laws. with out mounting the “gun” to a solid system you are loosing a large percentage of the force. i am assumin of cource that your “gun” is heavier than you “bullet”. if you were to mount the “gun” to a solid fixture and then fire at somthing all of the energy would be tranfered into the bullet and not into moving the gun. when you look at from the video it doesnt look like a large loss of energy but i could be. also if you were to use a magnitese projectial and then fire it will the opisite polarity you may have better results. and if your really really ambitious try multi stage. it is more effectent but also more messy.

Hey sweet project, but i have a question, what is the voltage and uf on each capacitor? iam trying to do some math as i am cheap and am using old capacitors off a psu. also what is more important the uf or voltage? and how does it all add up? 200 volts + 200volts = 400? or 200 uf + 200 uf = 400? oh also the capacitor my camera came with was 330 volts, 80 uf. (also i just want you to know that ur website kicks ass)(subnote: you kickass)(subsubnote: your gf kicks ass)

Hey Om, When capacitors are hooked up in parallel the voltage is the same across all the caps, my multi meter goes up to 2000 volts but this setup goes over that, so I really have no idea what the voltage is lol, but its a lot. Also when wiring capacitors in parallel the capacitances add, aka 100uf + 100uf = 200uf in series the capacitances are added using the formula, 1/Ctotal = 1/C1 + 1/C2 … aka. the total capacitance goes down. Thanks for the compliments on the site lol, I do what I can, hopefully its not painfully slow, godaddy is being a real bitch to me this week, I have to give them a call. Peace Om thanks for visiting!

Oh and about the capacitors being rated for only 330 volts… i just hope to god that they don’t blow lol, they are usually ok, only 1 has ever in my life, and the whole setup is inside the box so you should be ok, just make sure your protected lol.

hey matt um… does the voltage determin how powerfull it is or the uf.. if it is the voltage i need a couple more psu’s as i only have 400 volts.

Both the voltage and the capacitance determine the overall power, the formula for energy in a capacitor is Ec = 1/2 CV^2 aka the voltage matters more than the capacitance. Every time the voltage doubles the energy quadruples. Peace Om.

where does the switch with the black wires connected to it go to? what size project box did u get?

srry bout double post, another thought just came to me, there are other coil guns that have an LED light up when it is charged, can i do it with this model? is so, how would i go about doing that?

Yo Aaron,

The switch with the black wires goes from the capacitor bank to the coil. So when you flick the switch, the current flows from the capacitor bank through the switch and into the coil, thus firing the projectile. The project box is massive lol, I don’t remember the exact size but it has to be about 8 by 4 inches? It didn’t need to be that big though, I just had it lying around from another project. For the LED I think that if you just extended the wires going to the blinking light that comes on the camera you could just use that Thanks for the comment, good luck!

what do you mean it does from the capacitor bank to the coil, in the picture you soldered both of the ends of wire that are on the capacitor bank to the place where the first capacitor was. are u using the other end of the capacitor bank? or am i missing something?

also, where should the coil be placed, you put it at the end where the projectile is lying, but wouldnt it be more effective at the end of the barrel, so the projectile gets attracted to it until the end of the barrel, and not just at the beginning.

Yo Aaron,
The capacitor bank is connected to the charging circuit as well as the coil. When the switch is turned on the current flows from the capacitor bank into the coil. About the coil, if the coil was very far away from the projectile it would not have as much force on the projectile. Since the coil is only active for a very small fraction of a second the coil needs to be close but not too close. The coil on my gun can slide on the barrel so you can find the perfect location for each type of projectile. This location is crucial, and can be the difference between shooting through a can, and not leaving the barrel.

okay, so if i get this right the place where the capacitors are usually kept has one wire going to the capacitor bank and another going to a switch, on the other end of the switch, a wire going to the coil then the last wire from to the coil to the other place where the capacitor origianally was. am i right?

also, i dont know how to set up the button, its a press button, and when you lift off the casing, it has a concave piece of metal taped to it so when you press it in the metal makes contact with a small circle of metal that activates the swtich, where do the wires go, i can send you a picture if i had your email address.

i made a bad sketch of what i think you mean, is this what im supposed to do?

http://s457.photobucket.com/albums/qq300/Um0123/?action=view&current=scan0006.jpg

Hey I took a look at your pic and i fixed it for you k. http://img186.imageshack.us/my.php?image=fixedcircuithu7.jpg

thanks man, sorry for giving you trouble with all my questions, some things just confuse the hell out of me.

hey aaron, no problemo. Spread the word about matthack k?

Do you have a supply list of the items used so we can gather everything before we try to assemble?

can you use used cameras?

Of course you can use used cameras

Instead of paying for cameras, try asking for any cameras that have already been used at a place that develops the film. I got four for free, and I just asked to use them for a “science project.”