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136 Used Disposable Cameras

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flannelhead

Sat Mar 15 2008, 06:13PM

Registered Member #952 Joined: Mon Aug 13 2007, 11:07AM
Location: Finland
Posts: 388

BjÃ¸rn BÃ¦verfjord wrote ...

At least you have the opportunity to learn something very useful. Always try to verify your result using common sense and approximations.

Yep, it was just a *very* stupid mistake. I'll remember to verify all my results in the future now

Conundrum

Sat Mar 15 2008, 08:49PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

hehe.. I made a bank of 60 80uF photoflash capacitors for one of my projects.

I'm almost afraid to test it, got it up to 60V and the sparks were LOUD! made my 1F car capacitor look wussy

That said, it might be possible to use such a beast with a carefully designed air cored (to avoid saturation) transformer to generate 2V at some ungodly number of amps for spot welding.

-A

101111

Sat Mar 15 2008, 09:31PM

Registered Member #575 Joined: Sun Mar 11 2007, 04:00AM
Location: Norway
Posts: 263

I once had a capacitor bank that was made by photo flash capacitors.

They where in series and parallel 8x7. I charged them all with a MOT that was half wave rectified i took about 2 seconds.

It was a fun project and made allot of sparks and lightning, once i blew the walls in a cup filled with saltwater.

(NB: That capacitor bank almost killed me!)

Simon

Sun Mar 16 2008, 02:05AM

Registered Member #32 Joined: Sat Feb 04 2006, 08:58AM
Location: Australia
Posts: 549

Useful stuff:

The flash caps
Batteries
The xenon tubes (mostly for amusement - try hooking them up to all different kinds of PSU)

That's about it (although some people use the transformers and the cheapy lenses are worth keeping somewhere).

Oh and, yeah, the caps can be nasty. Taking apart one camera is no problem if you know what you're doing but it's easy to get complacent after several dozen. Remember: capacitors are never complacent in trying to kill you.

Andyman

Sun Mar 16 2008, 04:19AM

Registered Member #1083 Joined: Mon Oct 29 2007, 06:16PM
Location: Upland, California
Posts: 256

Make a single discharge stun gun?

teslaguy

Sun Mar 16 2008, 05:38AM

Registered Member #617 Joined: Fri Mar 30 2007, 07:29PM
Location: Buffalo NY
Posts: 49

I pulled out the boards and I calculated that all the capacitors can hold 773.6 joules at their maximum voltage. I think that i might build a giant disposable camera coil gun? or I could try drawing arc with an mot which could be fun as Ace7one suggested. Im afraid to remove the flash lamps from the boards but I started making parallel banks at or about 720uf each. I only have two done so far though. Do you guys think a .75kJ coil gun would be a bad idea? I also made a couple stun guns out of boards without the capacitors and I think that i might electrify the doorknob of my sisters room tomorrow xD. I appreciate all the replies, you guys rock. I still think that i can do something better though. Im going to get more cameras on monday on my way home.

Myke

Sun Mar 16 2008, 07:09AM

Registered Member #540 Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969

I think that the xenon flash tubes are fairly durable and I don't think you are going to break them by desoldering them. I've never had any problems with desoldering them. Just make sure the cap is discharged before doing anything with them because I've been shocked once with one cap while taking it apart. Does anyone know how hard they are to break?

101111

Sun Mar 16 2008, 10:20AM

Registered Member #575 Joined: Sun Mar 11 2007, 04:00AM
Location: Norway
Posts: 263

halomaster2004 wrote ...

Or I could try drawing arc with an mot which could be fun as Ace7one suggested.

That is not what i meant, i used the cap to blow up things to cause allot of sparks, lighting and very big bangs.
I believe that if you would charge the bank to about 2-3k KV then try to draw a spark the resistance in the spark would be so low that you would just short circuit it.

I used the bank for allot of coil guns experiments, using large MMC to blow a little capacitor etc.

Conundrum

Sun Mar 16 2008, 12:14PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

hmm.. well it might be possible to make a MMF (Multi Monolithic Flash) module, for high speed photography and/or laser experiments. The idea here is to solder the flash tubes together in a circular array with a reflector behind them, with wires wrapped around the tubes connected to your HV trigger.

The flash transformers can be used to build mini Geiger counters, as shown here.

regards, -A

[Edit: Image size

]

Sulaiman

Sun Mar 16 2008, 03:12PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

I have a bank of 12-series x 8-parallel x 120uF 330V photoflash capacitors from disposable cameras.
It scares the s**t out of me. (almost literally;-)
I measured the esr of the bank at about ONE OHM !
So at nearly 4kV it can discharge about 4,000 Amps peak !

Once I was measuring the voltage with a cheap dmm as it was charging, the range on the dmm was 1,999V.
Before it reached full-range there must have been an internal flashover - CRACK/KABOOM
The meter literally exploded as did the meter probe wires - in my hands.
I should know better - but we all make mistakes.

The danger is not just the energy stored, it's that the voltage is more than enough to overcome any skin resistance
and zap your heart with more than enough energy to kill - Rest In Pieces!
I suppose that in theory it would be like a de-fibrilator so there's a possibility of survival,
but I really don't want to test that theory.

So just because you've got a small low-power charger doesn't equate to any kind of safety - be extremely careful.

On the other hand, such a cap bank can blow stuff to pieces in a most spectacular manner :)

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