Build Your Own Stun Gun

mariox19 writes "Wondering what to do with your disposable camera when you're finished with it? TechTV has an article describing how to reach out and zap someone with a home-made stun gun. I discovered the link via Bruce Schneier's latest Cryptogram, where Schneier half-jokingly warns not to let airport security find out about this, lest (in their 'wisdom') they ban cameras along with nail clippers."

Comments

Stun Gun in a Camera...

[whiteranger99x]

And the best part is that you could zap them and capture the moment. Now there's a Kodak moment!!

Hmmm

[MikeXpop]

...Schneier half-jokingly warns not to let airport security find out about this, lest (in their 'wisdom') they ban cameras along with nail clippers

The first rule of Homemade-stun-gun Club is...

Way back...

[grub]

In junior high electronic shop class (~1978-79) we'd charge a capacitor up, say "Hey $NAME.." and toss it to the person. Force of habit dictated the person would usually catch it and get a nice suprise.

Re:Way back...

[metlin]

Actually, if you can have any kind of discharge, you can build a primitive coil gun/sten gun.

In my freshman year of EE, we used to build capacitor banks and use them to power our coil guns.

And another thing to do is to use Flyback drivers to discharge and use them to power hi-voltage stuff. Ofcourse, this knowledge came to us much later, but was useful neverthless :)

With a little bit of expertise, you can build a transistor flyback driver in a matter of minutes and do quite a lot of nasty things with it ;)

Re:Way back...

[nomadic]

I did the same thing, only even more low-tech. We'd take a styrofoam cup covered in tin foil, charge it with static electricity from a van de graf generator, and toss it to the person.

We had it even simpler in NYC public school. We'd shout someone's name, and when they turned around we'd shoot them. Good times.

Could they get banned at airports?

[wheresdrew]

Sure. Different airports ban different things. On a recent trip from Seoul to Tokyo, I had a pack of Duracell AA batteries confiscated by security at Gimpo airport in Seoul. Not rechargables or anything special like that, just plain alkaline AAs, still in the package.

However, when I was leaving Japan I noticed security at Haneda had no such rules. In fact, you could buy both alkaline and lithium batteries at the shops beyond the security checkpoint there.

I've yet to get an explanation for why plain batteries are considered a security risk.

Re:Could they get banned at airports?

[hypergreatthing]

They should just start banning passengers. If there's no passengers, there's no threat, right?

Don't think this is going to work to well...

[Caeda]

I suppose its possible that "some" cameras have the right hardware inside to make this. However, personal experience leads me to believe that there are cameras which will deliver just enough shock to piss someone off even more. In fixing a rather nice digital camera a while back, I just happened to touch the wrong wire and... ZAP!!! Ouch? Yes. A knockout? Definately not. Confusing, especially since the batteries werent in the thing. Put it back together, tried it, ended up charing the thing again. Took it apart again. Discovered another wrong spot to touch... ZAP! Equally painful the second time, but still no knockout... That time I ended up throwing the thing in a brief hand spasm which resulted in it landing on my leg and... oh no.. ZAP! That was number 3 and damn I hated that thing but it was still just painful and nothing like a stun gun should deliver. Heck. Not even as bad as picking up a damp laptop battery and having it discharge into you. That'll make your arm numb for hours ;)

Where's the love?

[sn0wman3030]

Did anyone else notice that the URL is http://www.techtv.com/unscrewed/IHATEYOU/story/0,2 4682,3653392,00.html ?

I can see the FARK now

[gravyfaucet]

"Bully breaks student's camera, low voltage hilarity ensues."

This is dangerous

[sploxx]

Yeah, capacitors on slashdot once again :)
But beware that this is really dangerous. I touched a flash capacitor some time ago, 40uF@400V are not really nice. 200uF@600V and I can assure you that you will fly across the room, hopefully surviving the shock. I have several 1uF@10kV caps, and I don'T dare to charge them to > 3kV (LOUD, risk of EMI, some PC failures already because of cap discharges)

Because this is all too destructive, here is a nice modification (I TAKE NO RESPONSIBILITY!!):
Leave the connection to the flash tube intact. Increase the capacity of the HV cap. Add capacitors salvaged from other cameras, or as a very cheap alternative, from PC power supplies.
Check the voltage rating. Often, they're rated at 800uF@200V, if your flash light operates around 200V, connect two of them in series (+ -)(+ -).

You can get nice, very *bright* flashes with this method. Do not add to much or the flash time will explode.

Problems here:
- NEVER touch power supply caps, they can store 10x - 20x the energy of flash caps. Lethal!
- Discharge the CAPs from the power supplies before salvaging.
- Discharge the unit after use with an *isolated* gripper, better yet, a high-wattage resistor (few kOhms) hold by an *isolated* gripper.

Someone said that more that more than 10 joule are dangerous, but I think you should not set an upper bound for harmless capacitors.

PS. Someone told me that you have to drink much liquid after an electric shock. Because it removes toxic products from your body which could result in kidney failure or so. Maybe the medicine-studying /.ers know more?
But... better don't let this happen!

Re:This is dangerous

[ColdWetDog]

"PS. Someone told me that you have to drink much liquid after an electric shock. Because it removes toxic products from your body which could result in kidney failure or so. Maybe the medicine-studying /.ers know more? But... better don't let this happen

Yeah, not a bright (so to speak) idea. When a significant jolt of electricity runs through your body, it can cause destruction of lots of cells (including those that do important things like regulate heart rhythm). When the cells get fried, the explode. If they're muscle cells (and you have lots of them even if you're a ninety pound weakling), they spill a protein call myoglobin. Too much myoglobin clogs up your kidneys. This isn't a desirable outcome. Since "the solution to pollution is dilution", pushing lots of fluids can help protect the kidneys. This is typical care for an burn patient (electric or otherwise) in a hospital setting. As the old saying goes, "do not try this at home..."

Actually, if you can have any kind of discharge...

[quonsar]

...you should see a doctor ASAP.

Yay, more uninformed stupidness on TechTV

[Powercntrl]

After watching a video where they take apart a MuVo2 for its Hitachi Microdrive and then say the iPod mini has the same drive (correct, but the iPod's microdrive will NOT work in any digital cameras), I'm convinced TechTV's "dark tips" have become dangerously innacurate.

Don't do this. Compared to a stun gun, a photoflash capacitor stores a lower voltage, direct current high amperage charge which is delivered all at once. Yes, if delivered across the heart, it could be leathal. If delivered across flesh, it will burn you. In almost no cases will it stun you other than the surprise of getting shocked.

Real stun guns use a high frequency alternating current, VERY low amperage spark. Real stun guns are also quite cheap on eBay.

If you want to make a joke shocker from a disposable camera flash, here's a much safer method:

Get a cheap disposable camera and take it apart. Discharge the capacitor with a screwdriver. Get rid of the capacitor.

Notice the heavily insulated wire running to the center of the xenon photoflash bulb? Remove it from the photoflash bulb and attach a longer wire that will go to one of you're "shocker's" probes. Make sure the connection is well insulated.

Locate the portion of the circuit board that is shorted to activate the flash charging circuit. Usually, it's a small flexible metal "button" with plastic over it. Yank that sucker off of there and short the points on the board out with solder, or if you like, you can attach wires and add your own on/off switch.

Get a battery holder, some sort of case to put all this in, and a momentary pushbutton switch. Attach the wires from the battery holder to the circuit board, a wire from Negative to your other "shocker probe". Connect the momentary pushbutton switch to the trigger circuit (usually two peices of metal that were positioned near the shutter). Position the probes to be less than 1/8" apart. Put all this crap in a box and try it out. When you press the momentary pushbutton switch, you should get a nice spark.

Re:Wow

[some guy I know]

the capacitors in a CRT monitor contain more than enough juice to kill a man.

This is why CRTs should be repaired by women.