View Full Version : iTouch Box Coil Gun

03-21-2009, 02:32 PM
I have always wanted to make one of these. We made crude liner actuator motors in high school electronics class but they had a fixed level of travel. Then about a year ago I was googling random things and came across a coil gun site. So I started researching and came up with a prototype that utilized 15 330v 80uF photo flash capacitors. This new Capacitor bank will contain 30 of those same capacitors. This will give me a stored energy value of 330v 2400uf. That's 100 Joules of stored energy if I got my maths right. Its no where near the energy that some people push through a coil to launch a projectile but I should be able to send an 8p nail with the head cut off through a soda can. That will be fine by me as I am not looking for something deadly , but rather a novelty to show off to other geeky friends.

This is where the warnings come into play. This capacitor bank stores enough electrical energy to kill you. If you short the leads from the capacitor bank with a screw driver the result will be a huge plasma spark , loud pop, and the wires welded to the screw driver. The flash is just as dangerous as the arch from a welding electrode so do no look at it with bare eyes. Unless you have experience with high voltage you should avoid trying this at home. I take no responsibility for you causing injury or death to your self.

So now its time for some photos..

The box my iTouch came in. The top is covered in blue tape and put to the side to prevent scratching.

1/3 of my capacitor bank. Its made from 330v 80uf photo flash capacitors I salvaged from used disposable cameras. For a working voltage ofXXXX

A close up of 1/3 of the bank.

I will be using the power switch out of an old HP case that was at least 10 years old. Its rated for 15 amps and will not be welded shut from the high voltage surge that will flow through it during firing. I will be powering the charging circuit with 2AAA batteries.

Top of the charging circuit. Also salvaged from a disposable camera. The LED will light up with the bank is fully charged. Notice that I removed the xeon flash tube as well as the capacitor. The 2 white wires are: 1 is for the switch to make the bank charge. The other will be the lead wires that will actually feed the capacitors.

The bottom of the charging circuit. The soldering looks a tad crappy but I will make it look better when I get a new tip for my Iron.

That's it for today. I will try to have more posted tomorrow. Thanks for looking and please comment.

03-21-2009, 07:30 PM
Cool project. Can't wait to see more. +rep

03-22-2009, 09:42 PM
Got a little more work done on the project today. After test fitting everything I realized that I will only be able to fit 20 of the 330v 80uF caps into the box. This will mean a loss of 800uF but I think I can compensate for that with the coil. You will notice that the charging board is a different one. I accidentally managed to lift a pad while re-soldering the wires for the charge switch. So I found a suitable replacement. Unfortunately I fried this board because I was not smart enough to realize that it was powered by a small 1v off sized battery and the magic smoke came out when I hooked the 2 AAA to it. To solve this problem in the future I will be re-wiring the batter holder to run the batteries in parallel.

Ok pic time.
I wanted a way to experiment with different coils to get the maximum distance and power out of it. Digging through my junk box I found a set of binding post. These should work nice.

Now where should they be mounted? To make the lid easy to remove to fix or change things I decided that the edge of the lower half would be perfect.

Holes drilled and ready for mounting.




With that finished I began wiring the coil pack up.

Finished with the long bridges and working on the short ones.

Finished with the first coil pack. I am 5 capacitors short from being able to complete this pack. These specific sized capacitors are found in Fuji Silver disposable cameras. I will make a trip to wal-mart this week and see if the photo lab has any used ones I can have. Last time I did this they gave me 3 bags full of cameras.

Test fitting things. Looks like everything is going to fit just fine.

another angle.

Soldering the lugs on for connecting the caps to the binding post.

Something every modder should have on the bench. I buy these at harbor freight for $3 every few months when they go on sale. I usually pick up 3-4 boxes of them because I hate using electrical tape.

And the goods inside.

Heat shrink on and ready to heat.

The finished product.

I stopped there for the day because I had a few steaks to throw on the grill and some basketball to watch while throwing back a few of the finest barley and hopps that Sam Adams has to offer. :twisted:

03-22-2009, 10:22 PM
:eek::eek:Words fail, I shudder to think how often you've been zapped to get the experience to try this.

A long time ago, my physics teacher showed us video he had gotten from a student's father. This particular father worked for the DoD. The video showed a rail gun that was yards long (memory fails). What I do remember was that it was accelerating what looked like an 3/4" acrylic plug and burning through a half inch aluminum plate.

Can't wait to see how this works but cripes, be careful.

03-22-2009, 10:39 PM
Rail guns and coil guns are 2 different animals. A coil gun uses electromagnetic pulses to propel a projectile. There is no exposed arc or plasma or anything to shock yourself on. They are silent (if designed right) and do have recoil but not much. A rail gun is very dangerous due to the velocities involved as well as the danger of shock, fire, and hazardous fumes from vaporized aluminum.

I have taken a few hits from a single fully charged 330v 80uF cap. It hurts and makes you think twice about doing it again. The last time I got zapped was from a 400v 180uF cap and it left a nice blister and my finger twitched for 3 days. I have not and hope to never take a hit from the full pack. I take every measure possible to prevent accidental shock when the caps are charged. I can not stress enough the dangers involved with high voltage capacitors. They can and will store the charge for years even if they are removed from the board and tossed in the trash. If any thing conductive shorts the leads it will discharge all of that stored energy in less than 1/1000 of a second and if the cap is large enough (rating not physical size)it can kill you. So please only attempt this if you are trained or have had experience with high voltages. My grandfather built ham radios and all sorts of high voltage gizmos from Tesla coils that made 4 foot sparks to vandegraff machines that would store millions of volts. I grew up with this stuff and was properly trained to handle high voltage.

03-23-2009, 02:17 AM
gunna be cool... me and my friends have been thinking of this one for ages... couldnt bring ourselfs to spend like 60 bucks on cameras tho :)

im very interested

03-23-2009, 10:21 AM
Cameras come free via any photo lab. Just ask for the used disposables. They just throw them away anyway.

03-23-2009, 01:13 PM
this looks neat :up:

03-23-2009, 05:08 PM

03-23-2009, 05:33 PM
I've been wanting to make a Coil Gun fr some time now. This is by far my favorite one:

Can't wait to see this up and running!


03-23-2009, 05:50 PM
That guy put much more thought into his than I did mine. Thanks for the link.+rep

03-24-2009, 02:18 AM
good work telling me that the cameras are free... now im gunna kill myself trying to make one :) thanks tho

03-24-2009, 11:23 AM
Please be careful. when you take the camera apart do not touch any thing on the circuit board until you short the leads of the capacitor with a screwdriver. Be prepared for a big spark and a loud pop. If it doesn't work the first time try it again making sure the 2 leads are shorted. If you want to be absolutely positive that its empty use a multimeter on the leads. Negative goes to the side with the big stripe.

03-24-2009, 11:46 AM
This is a pretty cool project. +subscription

03-25-2009, 02:38 AM
lol cheers :) yeah they hurt when they zap you :)

03-27-2009, 11:40 PM
This is a simi final update. Meaning that the electronics and construction is finished. (I still need to get 10 more of the 330v 80uF capacitors and build the second bank) But other than that the only thing left to do is cosmetics. When the bank is finished I plan on wrapping the bank with a graphic designed by you that warns of high voltage and the risk of death. More on that in a minute.

Ok so I am on my 4th charging board because I was trying to over power the board with 2 AAA. So I needed a single AA holder. Still sticking to my goal of building this with what I had I found a 4 AA holder and cut it down to size. Sorry I have no photos of the full piece, but I forgot to put the card in the camera for the first 4 shots. So here is the AA holder rough cut.

It was a tad over-sized and was taking up valuable space so I broke out the old piece of plexi and sand paper and sanded the sides down.

Rounded the corners and used a lighter to remove all the fuzz.

I used hot glue to secure the AA holder to the base.

I needed a switch to turn the charging board off so it was not always charging the cap bank. A simple rocker switch will do the trick. Wait... It needs a hole.

I did not have a good photo of the hole cut out so this will have to do. In this photo you can also see that I have soldered and heat shrunk the leads of the switch and wires leading to the board.

This is a shot of the iPod Touch case all sealed up and everything in place. The Battery holder and board are held in place by hot glue. The cap bank is just there until I can get enough of the proper sized caps to finish the bank. The case is held together by Duck Crystal Clear packing tape.

Another shot of the case all closed up.

This is my favorite shot of the week and I have taken a lot of bridal and senior portraits this week. I charged the cap bank up and put 2 pieces of 18awg wire on the binding post. Then held one in place with my helping hands. Grabbed the other with some insulated needle nose pliers. With camera in hand I pressed the shutter button and then touched the leads at the same time. The stuff you see flying away is molten solder from solder that I had wrapped around the wire. The flash was very bright and very very loud. Please do not try this at home.

Here is where the molten solder landed. My arm. Yea it hurt. Its what I get for playing around and being careless.

Ok so about that contest. I am going to post something about it in the graphic art forum so check it out here http://www.thebestcasescenario.com/forum/showthread.php?p=237286#post237286

Drum Thumper
03-31-2009, 01:01 AM
I inadvertently popped one of those caps from a disposable camera a few years ago with a poorly designed screwdriver (probably from Harbor Freight). It tingled a little bit.

And scared the living piss out of a co-worker.

Interesting work so far, can't wait to see the end result!

03-31-2009, 01:42 AM
Thanks DT. I have to stop by wal-mart tomorrow and pick up a box of disposable cameras they have been saving for me. The lady called and said it was full. So I am guessing I have 50 or so cameras to salvage more caps from. My sister is having her baby tomorrow so I wont have time to work on winding the coil tomorrow but maybe later in the week I will get to.

03-31-2009, 02:05 AM
cooleo looking forward to it

08-04-2009, 02:51 PM
good work telling me that the cameras are free... now im gunna kill myself trying to make one :) thanks tho

Photo labs will also give away film containers (you remember what film is right?). These are very useful for storing loose change and a large variety of electronic components, like leds, chip holders, resisters, etc.

One thing they don't usually give away is their silver drum. Too bad, imagine the plating you could do with that stuff... :)

BTW, check out my photos of me shorting one of those disposable photo PCB's, (one capacitor and one capacitor only). My post from Alien Autopsy: The Death of an Alienware Powersupply (http://www.thebestcasescenario.com/forum/showpost.php?p=251658&postcount=24)

BTW +Rep!

08-04-2009, 05:50 PM
I can't wait to see this project finished!

05-03-2010, 07:24 PM
is it done yet?

05-07-2010, 01:17 AM
It was finished a while back and I somehow lost the actual coil gun I wound for it. I could stick finishing nails into a soda can at 5 feet with it. At point blank it would pass through both sides of the can. I might paint it and wrap a new gun this weekend.