Picture of Make a cheap disposable camera capacitor bank
explosion square.jpg
This instructable will show you have to make a simple capacitor bank and charger out of old disposable cameras that you can get for free at your local store.

You can then use it for powering things such as coil guns or just blowing things up! See the second picture above? that was the spark created when I discharged such a capacitor bank. It was also very loud too!

The video below is the bank being discharged through various items including thin wire, transistors, resistors and headphone drivers of all things.

Remove these adsRemove these ads by Signing Up

Step 1: Parts list

Picture of Parts list
You will need a few items to make this.

A few disposable cameras. You can get these from places like Tesco and Walmart for free, all you have to do is ask at the kiosk where they develop camera film and they will usually give you a bag full of disposable cameras for free! I once got given 20 of these at Tesco.

Wire. This is needed for connecting things up.

Veroboard/strip-board. You don't HAVE to use this but it helps when it comes to soldering and makes it look neater.

Solder+soldering iron. For soldering electrical connections of-course!

Electrical tape. Not essential, but useful for holding things in place and covering exposed high voltage electrical connections.

Terminal block. For connecting a discharge stick to the capacitor bank. Because of the high peak currents flowing, alligator clips are not suitable and will just spark becuase they just don't make good high current ultra-low resistance connections. You can however use them for connecting the charger to the bank or connecting the battery/power supply.

Also you could just use solder, I used the terminal block so I could easily pack the bank away.

Tools. A metal screw driver with an insulated handle.

I am in no way responsible if you mess up with this circuit. If you mess up, receive an electrical shock or burn your house down whilst making this circuit you have no-one to blame but yourself. By following this guide in order to make this circuit you agree to accepting all liability if something were to go wrong.

I will answer and try to help with any questions you have via the comments.
That was the best disposable camera intructable. I'm thinking of connecting four circuits togather to charge faster, I tried it 4 minutes ago and putting two togather charged the cap. Bank in half the time!! So I was thinking, which is better?

1- to connect the circuit battery and charging in parallel.

2- to connect the circuit battery wires in series and giving them 6v while the charging cap. wires are in parallel?


Thank you.
dtburford1 year ago
thanks dude, this was very helpful, I'm aiming to use it in a school project :-)
dew_it1 year ago
So how do you make the fast charger then? Cus I have now gathered a selection of capacitors with a total capacitance of 25434 μF with the lowest 'max voltage' at 10 V.. Should be good if I can get it to charge relatively quick right?
Alex1M6 (author)  dew_it1 year ago
Basically its just a home wound multi-tapped transformer being driven by some form of push pull driver, secondary side rectified by some fast recovery diodes.

Some form of feedback loop (comparator, opto isolator etc) is used to turn off the driver once the required voltage is reached.
dean141112 years ago
hey on some of your videos you have a toggle switch on your cap bank, im building a cap bank and charger in one. do you use a "special" toggle switch because of the high voltage? PLEASE reply
Alex1M6 (author)  dean141112 years ago
This switch just connects and disconnects the low voltage power supply (12-36v) for the step up transformer driver. Its just a standard mains rated switch that you can get from old junk or electronics stores (I found mine in an old CRT TV and it came with an insulating sleeve).

To connect and disconnect the high voltage side I use a PVC pipe with a bit of metal on the end ("chicken stick") which is connected to the negative side of the capacitor bank, this results in a bit of a bang when contact is made with a wire connected to the positive side ( :

If you use a mains powered supply then its a good idea to earth ground the negative side of the capacitor bank.

If you wanted to go solid state for the high current switching then an SCR is the best choice for high voltage and high current peaks. Its sort of like a high current transistor.

Hope this helps.
so how do you blow up diodes and resistors? (because i can see in the video you have alagator clips attached to them before they EXPLODE!!!) PLEASE reply
jross212 years ago
Needin some help I got the whole thing up and running but when I went to charge up the second time nothing only getting power to the power terminals on the board. ??? Cheers
jross21 jross212 years ago
O and after the first time that happend I switched boards and same problem only one charge then nothing. ?
Alex1M6 (author)  jross212 years ago
Not sure, could your tracks/wires be blowing becuase of the high peak currents? I would check everything with a multimeter to be sure. Make sure the charger is putting out voltage and that is being reflected on the banks rails.
nator_exe2 years ago
this instructable can be used to make a welder? i want it to weld some tabs to CR2032 batteries
Alex1M6 (author)  nator_exe2 years ago
You could try it but I don't think it would work very well since you need steady heat for a few seconds for that sort of thing, this just gives a sudden big burst that lasts for a few milliseconds (creating pit marks in the battery's and making them look not so nice neat).
mochimaster2 years ago
That is obviously AWESOME.

But concerning safety… I now see that from "Snerdguy"'s comment, it has enough charge to kill you. While taking apart a camera, I also got shocked by a small 330 V capacitor, lower current, so imagine what it's like to multiply that! What is the exact voltage here? What is the current?
Alex1M6 (author)  mochimaster2 years ago
Voltage here was around 310-320v since I use a custom charger. I have 21 caps on mine which gives me 2180uF.

Not sure on the peak discharge currents, but it can vaporise thin wires easily.

I actually made one of those little deodorant spray based cannons and used a small HV pulse transformer and a small HV capacitor across it for the ignition, worked quite well although that cap was only a few nF at most!
flamekiller2 years ago
If you need cheap desoldering wick (a few feet of the "real" stuff is $-something for five feet ... Preposterous!), salvage some old TV coaxial cable. Strip the sheathing off and recover the woven shielding from inside the cable. Pound it flat on an anvil (substitute "concrete driveway" if you don't have an anvil) and bam, cheap, effective desoldering wick. Probably works better than most solder pumps too.

The added bonus is you also end up with a medium gauge insulated solid conductor (strip this and wham, cheap effective bus wire!).
mochimaster2 years ago
I was also thinking that you could make a neon bomb with it.

But some pressurized neon in a jar or container, and put that spark plug/capacitor bank, and let it explode in the jar. That must look awesome.
dean141112 years ago
i made one before you posted this inst, but with one differance. i took the capasitor off the charger and put it in the bank. can you please tell me why you left it in the charger? please reply.
Alex1M6 (author)  dean141112 years ago

It makes no difference, the only reason I said to keep one circuit board with the capacitor on was so that people making this will know which side is positive and which is negative.

It makes it a bit less confusing for a beginner when it comes to connecting the charger to the rest of the capacitor bank.

oh ok thanks
R.A.T.M2 years ago
Haha about 8 months ago i finished mine mines 100 330v 180uf caps all wired up it rocks the house when it goes off
codycool552 years ago
Could this be used instead of a capacitor? What are the practical uses?
Alex1M6 (author)  codycool552 years ago
Electrically, the whole bank acts like one big capacitor. You could use it to power a coil gun or if you want a good experiment, discharge it into the primary coil of an ignition coil (with the HT wire close to ground) and you will get some good arcs out of it.

I was able to get 4-5 inch sparks out of one.
Can you elaborate? This IS a capacitor... it's just made up of smaller capacitors.

Are you talking about the Large capacitor in a Car stereo system?
Alex1M6 (author) 2 years ago
I (unintentionally) did this with just a few capacitors charged to around 300v and it was very bright for a brief second, then there was a small "pop" sound and it went out.

Upon closure inspection one end of the xenon tube was burnt black and there was a small crack in the glass, not to mention still quite a bit of charge still stored in the bank.

If I did it with my current bank I think the xenon tube would potentially explode so a blast shield would probably be needed along with eye and ear protection.

Wizzkid19842 years ago
this looks like so much fun!!!
Alex1M6 (author)  Wizzkid19842 years ago
Thanks, yes its good fun but you have to remember to play safe ( :
Lol u need to be safer bro
Alex1M6 (author)  fostersfriend2 years ago
I live on the edge ( :
Treknology2 years ago
I have one of these units fitted to the inside of the door handles on my car (each with only the ONE capacitor). If someone tries to lift the handle while the alarm is active, he gets a good jolt across the finger tips and is unlikely to try again.

Note that in normal circumstances the shock is only delivered across the fingers because both poles are represented under the door handle. The risk of a discharge through the body to 'earth' is extremely unlikely, and it's much safer than those under door flame throwers that are proving popular in South Africa.
Alex1M6 (author)  Treknology2 years ago
I have been shocked by one of these capacitors (just one on its own, not by the bank!) across the chest before when I first took apart a disposable camera years ago, and they do pack quite a punch!

Flame throwers in car doors!? They would never allow that here!
Yes, seriously. Car-jacking is an epidemic in South Africa and cars are fitted with a small LPG tank so that if someone is attempting to get you out of your car, you move your left foot beyond the clutch to activate the flame thrower. It gusts out far enough to seriously injure the would-be car-jacker, and doesn't ruin the paint on the car either.
not a bad thinkin Trek
I also have two very fine stainless wires threaded through the driver's seat. One is earthed, the other goes to the ignition coil. When one goes to start the engine there is a beeper to remind me about the kill switch, but your average their is going to ignore that and start turning over the engine, isn't he?

You can tell I've lost a couple of valuable cars, can't you?
MPaulHolmes2 years ago
very very cool!!!
Alex1M6 (author)  MPaulHolmes2 years ago
Thanks ( :
Snerdguy2 years ago
While it has some very interesting applications, it should be made clear that the capacitor bank can hold enough charge to kill you. It should be handled with great respect and kept drained with a shorting resistor when not in use.
Alex1M6 (author)  Snerdguy2 years ago
Thanks, I actually dedicated an entire step to the safety aspects of such a project and I have also put in reminders throughout the instructable. That should be enough warnings for people.

I also already covered how to correctly store the bank and about keeping the bank shorted out when not in use.