Disposable camera coilgun

 by AlfonsVH

Step 4: Assembling the coilgun

inside.jpg
- 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.
 
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fire_fly21 says: May 2, 2013. 9:29 AM
question? is it muzzle loaded, is it a chamber load of sorts?
Liam.great98 says: Mar 9, 2013. 5:33 AM
I'm going to make this some day when I can get enough disposable cameras.
StandingRobotNextToMenus says: Mar 27, 2011. 3:17 PM
I don't get it, how does it charge?
Liam.great98 in reply to StandingRobotNextToMenusMar 9, 2013. 5:32 AM
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.
alvin9861 says: Jun 11, 2009. 9:15 AM
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.
positr_n in reply to alvin9861Dec 2, 2011. 12:27 PM
what do you use to power the ignition coil?
Electronics Man says: Jul 14, 2011. 7:51 PM
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?
LeelaKrishna in reply to Electronics ManAug 21, 2011. 4:29 PM
yes
R.A.T.M says: Jun 8, 2011. 6:12 PM
pleas help if i have the coil coring the hole pen but 1 1/2 inch n the front
lakevista5 says: May 24, 2010. 8:38 PM
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?
badideasrus in reply to lakevista5Oct 22, 2010. 8:08 PM
what kind of power were you getting? cuz i want to make a rail gun on a simmilar bank (actually about twice that....), and an interested in your results...
Darwinfish in reply to lakevista5Aug 16, 2010. 1:43 PM
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.
Purple Guy in reply to DarwinfishFeb 16, 2011. 1:46 PM
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.
S33PlusPlus in reply to Purple GuySep 7, 2011. 12:16 PM
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.
Purple Guy in reply to S33PlusPlusSep 11, 2011. 12:37 PM
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.
Speedmite in reply to DarwinfishAug 16, 2010. 7:53 PM
You could also make a bigger(longer) coil or use thicker wire. This would allow the electricity to pass quicker, maximizing the use of your cap bank, and not overkilling the coil
cooliodudeperson says: Jul 17, 2009. 9:37 PM
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?
alvaromanuel in reply to cooliodudepersonNov 29, 2009. 7:22 AM

yes
KhronosDiavolos in reply to alvaromanuelSep 3, 2010. 2:12 PM
actually no, you have to wrap the wires the same way every time. otherwise the electromagnetic fields would cross with each other and cancel each other out.
brooklynlord in reply to KhronosDiavolosOct 5, 2010. 9:00 PM
The charger will put out around 300v. Capacitors will blow up if their voltage is exceeded too much. If you hook up capacitors in series, the voltage increases when the capacity decreases. In parallel, capacity will add up while voltage stays the same. So 100v caps in series would be okay, but you have to be careful because u really should use bleeding resistors. With 330v capacitors, feel free to hook them up in parallel. (on a side note, if capacitors all discharge and one discharges early, the capacitors can discharge through the early discharged capacitor and blow it up.....)
brooklynlord in reply to brooklynlordOct 5, 2010. 9:03 PM
Whoops. It glitched.

i thought electromagnets only had 1 "polarity," so it would attract iron no matter how i wind the coil.
badideasrus in reply to brooklynlordOct 22, 2010. 8:01 PM
.... well, no matter the polarity, it will still attract the iron....... simple test is to take a magnet and put it on metal, first on side, then the next. it will still attach.

scientists actually have yet to make a magnet with only one pole, so that would be pretty amazeing if you did it with a simple electromagnet.....

like it was said befor tho, wind in the same dirrection. it shouldn't matter which way though.
freerunnin1 says: Aug 28, 2010. 12:47 AM
does anyone know the best type of wire for a coil gun coil?
Ben The Builder says: Sep 13, 2009. 7:50 PM
Is it the same camera circuit just with extra capacitors?
alvaromanuel in reply to Ben The BuilderNov 29, 2009. 7:21 AM
well you can make a very simple one just add more caps to the camara and take out the light put there a coil
patlynz says: Aug 26, 2009. 10:08 AM
which one is the light switch?
patlynz says: Aug 26, 2009. 9:56 AM
which one is the light switch?
markubiak says: Jun 4, 2009. 9:53 AM
I'm using coated 12 gauge copper wire. Will this work?
kevincai96 in reply to markubiakJun 27, 2009. 5:24 AM
Of course. However, because 12 gauge is much thicker than the commonly used 22 gauge, wind less layers. (for example, one inch long coil, 4 layers thick). Hope this helps!
anubreed says: Nov 11, 2008. 11:48 PM
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.
cyrozap in reply to anubreedJan 9, 2009. 2:42 PM
Copper wire would just short. Magnet wire has enamel on it so you can wrap it without it shorting itself. Yes, it is the kind of wire that's wrapped around a square block inside a radio.
amando96 in reply to cyrozapJan 29, 2009. 7:50 AM
yea but the one inside a radio is really thin, and has better use for radios... xD
cyrozap in reply to cyrozapJan 9, 2009. 2:43 PM
"Bare copper wire would short" is what I meant to say.
aodshocky says: Aug 10, 2008. 6:42 PM
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?
Mattrox says: Apr 11, 2008. 1:57 PM
What sort of wire can i use? and will it matter if i use capicitors from different cameras?
Magre1441 in reply to MattroxApr 27, 2008. 7:59 AM
No it wont but what kind of wire for where? The wire to the coil would have to be at least 14-12 AWG.
Mattrox in reply to Magre1441Apr 29, 2008. 2:06 PM
thanks i meant the coil anyway. what does awg and where can i get it from?
Magre1441 in reply to MattroxApr 30, 2008. 12:54 PM
The coil should be magnet wire prob 16 or 18 AWG. AWG stands for American Wire Gauge, its just a unit of measure not a type of wire.
vorian says: Mar 31, 2008. 10:57 AM
`yeah how do you see the little boxes?
Einsteins Circuitry says: Oct 29, 2007. 7:07 AM
Wait... So how long should the coil be? 2.5 cm or 2-5 cm?
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