Step 4: Assembling the coilgun

Picture of Assembling the coilgun
- Desolder the wires connected to the flash tube (and to the reflector attached to it) and mark the places where the two main wires were.

- Wind a coil using the enameled wire and the plastic ballpoint-pen. Do this by turning the wire around the tube. The coil should be about 2,5cm long. Wind several (about 10) layers on top of eachother, but don't forget to insulate each layer with electrical tape.

- Scrape off the coating of the enameled wire at the ends of your coil; enameled wire-coating isn't conductive

- Solder one end of the coil to one connection where the flash-tube was before. Solder the light-switch to the other end of the coil, and the other end of the light-switch to the other flash-tube-connection.
question? is it muzzle loaded, is it a chamber load of sorts?
I'm going to make this some day when I can get enough disposable cameras.
I don't get it, how does it charge?
Inside the camera, when you hold down the button for flash, it charges the capacitor. Snce tou added a few more it might take longer to charge but it charges them all at once. Then when you press the take-picture button it discharges the capacitors to the flash. Little does it know the flash has been replaced with a coil.
alvin98616 years ago
I'm using an old paintball gun for kicking the round stock to the coil. I took out the guns barrel and made a new barrel with my coil on it . I use an auto ignition coil for my power source w/out caps. It does very well w/out the caps and can fire rapidly w/out constant charging.
what do you use to power the ignition coil?
lakevista55 years ago
I made a Coil gun using 15 capacitors with a total 300v and 1880uF with a single stage coil.  My coil is 39mm long  and 5 layers thick, using 24gauge magnetic wire.  the problem i am having with the gun is that it shoots backwards.  at 100v it shoots forward, at 125v to 175v it does not shoot at all and 200v to 300v it shoots backwards. 

what should i do... should i decrease the number of capacitors, increase the voltage or change the coil.  if the coil is the problem what size would you recommend?
Sorry if this is a bit late, but.... from comments on a similar instructable I'm betting that what's happening is that your coil is energized long enough for the projectile to get sucked back through again after launching the right way. Maybe move the projectile farther back from the coil? That way it's got longer to accelerate forwards before the coil's pulling it back.
I suppose you may be able to use some kind of Micro-controller chip to only allow electricity through the circuit for a short time (milliseconds, for the ammunition to go from the loading end of the barrel to the midway point) and then it could let the projectile shoot out the firing end without any sort of backwards dragging force from the magnet?

I am only a novice (if that) to electronics so I have only little knowledge on how well this would work.
I would be careful when introducing semiconductors into the coil stage of the gun, and would be *extra* careful when hooking it in any way to a microcontroller. The difficulty is two fold:
problem number 1 is you have the capacitor discharging into the coil, and according to ohm's law, current is directly proportional to voltage for a given resistance. The instantaneous current from that 330V cap can easily be hundreds of amps, and I have yet to see a *common* transistor survive that rush of power when you flip that discharge switch (in my experiences they'll likely fail in the most explosive way possible). Hook up a transistor you don't mind killing in place of the coil and you'll see what I mean.

Problem 2 is the coil is a giant inductor which you're passing very large current and pretty high voltages through. When that field collapses it'll induce *more* current, which has to be anticipated and dealt with, It's the same reason you can't hook a motor directly to an arduino.

I'm not an expert, so some of the details could be off, but in my personal experience, I haven't found a way to use commonly available parts to control a coilgun due to the incredible amount of power they'd be subjected to.
I do agree these all seem like major problems.

To resolve problem one I would, with my minimal knowledge, try to add a high operating voltage relay switch into the charging/discharge circuit, though if this works it would be hard to implement into an instructables due to the many different commercial circuit designs for flash op boards from cameras.

In regard to No. 2 I have very little knowledge of inductors but could you add another inductor which will take away the problem into a suitable circuit.

These are my novice ideas so can people please correct me and suggest suitable solutions.
Do the capacitors have to have the same rating if I wire them in parallel? I have 2 80uf, and 4 160uf but they have different voltage ratings. Can I use all of them together?
R.A.T.M4 years ago
pleas help if i have the coil coring the hole pen but 1 1/2 inch n the front
freerunnin15 years ago
does anyone know the best type of wire for a coil gun coil?
sorry if this is a stupid question but when you make the coil do you wrap it one way, stop at the end, then wrap it back the other way so that you have 5 or so layers that go right and 5 or so that go left?

Is it the same camera circuit just with extra capacitors?
well you can make a very simple one just add more caps to the camara and take out the light put there a coil
patlynz6 years ago
which one is the light switch?
patlynz6 years ago
which one is the light switch?
markubiak6 years ago
I'm using coated 12 gauge copper wire. Will this work?
anubreed6 years ago
When you say magnet wire do u mean copper wire. or is it that kind of wire thats wraped around a square block in side a radio or some thing and if so can i just unwind it from that and use it for this.
aodshocky7 years ago
I have a question on the coil creation. lets say I start on the left and wrap it to the right, when I get to the right hand side do I pull my wire back to the left and restart on the left going right again OR do I go back to the left?
Mattrox7 years ago
What sort of wire can i use? and will it matter if i use capicitors from different cameras?
vorian7 years ago
`yeah how do you see the little boxes?
Wait... So how long should the coil be? 2.5 cm or 2-5 cm?
AlfonsVH (author)  Einsteins Circuitry7 years ago
Two and a half cm
Namlem8 years ago
what do the two little boxes say? I can't see them because of the big box.
dumdog9278 years ago
my kodk came with a press thingy button to make it charge ho can I ive it a different switch+