Learn how to make a simple coilgun using only a few parts that are fairly easy to obtain. Be Willing to spend more than a week on this and you might need a few heavy power tools (Only to make good projectiles). I built my first one in only a week after I had all the parts.

Coilgun Principal:
Coilguns(Pulse Accelerators), like railguns(Linear Accelerators), use intense electromagnetic fields to propel objects at incredible velocities unreachable with modern gas driven weaponry (given enough stored energy of course). This coil gun is known as a reluctance coil gun. The coil uses its electromagnetic field to pull a ferromagnetic (magnetically affected) projectile, in this case a shaped steel round, toward its center. Ideally the current supporting the electromagnetic field will turn off when the projectile is in the center allowing the projectile to continue traveling down the barrel, out the gun, and to the target. Use a coil and a few batteries to understand the properties of this system better. Many coilguns incorporate multiple stages at lower energy levels as efficiency tends to die off as more Stored Energy is used for a single coil design. For more information go to step 5.

A basic coilgun operation diagram is included at the bottom.

'!!!!!!Learn More About Coilguns!!!!!!'

What is a relay?? (Elaboration on step 2)

How does it work?
A relay is a simple electromagnetic switch. It uses an electromagnet to pull two contacts of a separate circuit together, completing the circuit and allowing electricity to flow.

What is it used for?
A relay was originally used to allow a machine or computer to switch something on or off electronically. In this application it is used to switch the capacitors energy into the coil.

Why use it?
Relays allow more current to pass through them than regular push button switches, which normally weld together. You can use a very high rated toggle switch for this, but it is usually more expensive and larger than a relay of the same rating.

Part Deals

The Parts You Need Are:

From Radio Shack or Other Electronic Parts Dealer:
-20 or 22 AWG Hookup Wire (Buy both the solid and stranded)(Larger wire is better because it lowers the resistance in the system which increases the coil gun's efficiency)
-22-20 gauge Magnetic Wire (Depending on your coil preference;See step 2)(Radio Shack has a Package with 40 ft of this but I recommend buying it from a different store to save cost and to get at least 100 ft for a coil more than 7 layers thick)
-A Relay (Electronic Switch), Preferably 30 Amps or more (I got a 12VDC/30A SPST Automotive Relay from Radio Shack, but I would recommend a higher voltage and current rating)
-A Momentary Switch( I used the SPDT Switch with 3/4" Roller Lever from Radio Shack, but you can use a lower rated switch)
-An On/Off Switch(I used the DPDT Heavy-Duty Rocker Switch from Radio Shack but you can use a lower rated switch)
-Battery Packs (More than 2 2AA Holders and 1 9V Holder)(The more 2AA Battery Packs the better)( I would suggest getting a few 2 C Battery Holders as they provide substantially more power to the Charger, resulting in a MUCH faster charge time; be careful not to over load your chargers, see last step for safe charger to battery ratios.

From Other Places:
-Used Disposable Camera's (The More The Better as this is the gun's central component), You can get them by asking most photo places like in Walmart or CVS for used disposable camera's. Remember: it is for the batteries, not a gun...never
-Straws from Burger king or local chain(You May use another place's straws but the coil's inner diameter will differ; Of course if you choose a smaller straw a smaller projectile will go faster but not pack as big a punch, AKA momentum)Also,Smaller Straws may be used to place on the back of your projetile for stabilization, this works well.
-Large Nails (3/16 to 1/4 inch Diameter, or bring your straw to Home Depot to fit the right nail)
-A Bolt, two washers, and a nut. (The bolt needs to be the diameter of your straw and the washer needs to fit well and be as wide in diameter as possible)
-A spray paint "can gun" handle or other handle. (I got mine from Harbor Freight)
-Plexiglas, wood, or sheet metal(Optional for gun casing)
-Electrical Tape
-Flux (Not necessary, but it does help)
-Super Glue/ Epoxy/ Hot Glue(Used for gun casing)

-Wire Cutters
-Wire Stripper( A big help)
-Glue Gun( For outer casing)
-Screw Driver(Flat Head)( To get cameras apart and discharge capacitors)

Losing Drive To Build This? Check out The Videos

The PAR-1 video demonstrates the kinetic output of a 12 layer coil with a 470uF 400V(to 450V) capacitor, that's only 50 Joules!.

Finished a coilgun and want to share it? Post it Here: Coilgun Arsenal

Useful Electronic Goods Sites:
- Mouser Probably the best Distributor I've come across, vast selection of items, best pricing for a non-wholesale electronics site, and great navigation and organization.
- Goldmine Great prices on useful parts
- Digikey Good for hard to find parts.
- MPJA Great place to buy magnetic wire and LEDs
- Electrostore Large high voltage capacitors at cheap price and other high power components.
- Surplus of Nebraska Great prices on magnetic wire if bought in large quantities.
- Alltronics An OK surplus store



Step 1: Charger Circuits

The first Step is to dispose of the disposables. Take apart the Kodak cameras first by using a screw driver to pry the case open on the side. Remove all but the center plastic part that holds the circuit board (BE CAREFUL, OR don't either way you will probably shock yourself unless you wear gloves, a good idea for the weak of heart(literally)) Make sure the battery is out then touch the capacitor's leads together with a screwdriver to discharge it, the capacitor is the cylindrical device that has two leads extruding from it, location shown is second picture.

Why connect chargers into a bank?

chargers themselves aren't very powerful, but when you connect them together in parallel like shown in the last picture you increase the possible power output that the chargers can handle. Increasing the number and size of your battery bank (at 3V) will increase the chargers output (to a point) until the chargers fry.

Connecting the chargers in Parallel OR Series?

The chargers are connected in parallel, i.e. each terminal is connected to the same terminal on the adjacent charger as shown in the picture diagram. I do not recommend putting the chargers in series, so don't worry about it.

Look and read the picture comments, the pictures show you how to make your chargers better than I can describe it.

First take your circuit and use a pair of wire clippers and cut off the section defined by the small transformer on the top right of the circuit (this includes a transistor and diode)(look at the picture for reference). Attach leads as defined in the picture.

Camera circuits are mostly inefficient i.e. 16% by my testing, if you want your gun to charge faster and with less battery drain check out my DC to DC HV Boost Converter.

The Mini Charger Idea credit Comes from Instructable member "245Tommy" who got it from you tube member "Halo2maniaccc". Thank You both


Remember: Flux/Rosin (Which is used to enhance solder's "stick") is important here. You do not need it, but it does help a lot.
<p>Do you think it would be possible to place a smaller projectile in a nerf gun bullet tip and have one of these guns accelerate that?</p>
It would be hard to get ot to accelerate enough to launch, or to make it slow enough not to kill a small child. <br><br>NOT suggested for dart tag, but yes you could do it for a nerf sniper
Yes, and no. It would work, but might kill someone anyway.
<p>the circuit boards from the Kodak disposable cameras I got look different than the stuff in the pictures, do I need ones that look the same as in the pictures?</p>
<div><div><div>Hello<br>How do I download content?<br>Can you email me the pdf form?<br>my email is:dr.hosseinnasiri@gmail.com<br>thanks<br></div></div></div>
<p>hello</p><p>hello my Friends</p><p>How to build a coil gun<br>What is needed components list?</p><p>thanks</p>
<p>What did you use for the case?</p>
<p>how do i load it?</p>
<p>I really want to make a nerf gun using this method :)</p>
do coilguns require high voltage or high current <br>
<p>High current is what you need.</p>
<p>every time i try to get mine to work it just wont BUT if i disconnect the capacitor bank and the coil wire from the relay, the capacitors actually charge up and then when i touch the coil wire to the + capacitor wire (thus completing the circuit) it will actually discharge the capacitors and shoot. im not sure what i am doing wrong to make it not fire with the relay/switch combo but i need it to and im stumped...could i be using the wrong relay or something?</p>
<p>Hello, I was wondering if you could just use a capacitor at say, 2.7 volts and 100 farads (370-some joules) to get the same result as using a capacitor that has around 600 volts, but very low capacity. Just wondering if the voltage matters even if it has a very large joule value. Thanks.</p>
<p>Btw i once saw a 15kJ 2.5V capacitor somewhere for around 800$, would that even work? (probably in a line so they make some more volts and 100mm&sup2; wire)</p>
<p>I got a 385V/2200&micro;F (163J) capacitor, and got a small coil (~0.2mm wire diameter) to fire an iron core half a meter far (it was charged to ~25-44J), so a thicker coil would surely work?</p>
I am having some trouble im trying to do this with an electric weed eater any advice
<p>Electric weed eater.. well, I'd suggest to put that down, and try using the suggested components instead. Good luck!</p>
<p>does someone knows how to charge a capacitor?</p>
<p>apply current</p>
Sorry again, decrease*
Sorry again, decrease*
Would it decrease charging time if you were to use more than one charging circuit, turning them on one at a time, and having them linked in parallel to the bank?
<p>I have fawned a way to make the coil gun a automatic. I put a lm555 timer ,but you can use any of the 555 chips, to make it a automatic gun.</p>
If you were to make a coil gun with just a single disposable camera circuit, you would just need to apply the power bank to where the battery would have gone, with a switch also on the positive wire, and apply your coil (with your lever switch on the positive wire) to the capacitor. (positive with positive, negative with negative) now if you used eight circuit boards,( keeping in mind on how I explained a single circuit board coil gun works) line them up in series, with each capacitor removed from them and put into a separate bank, the boards would all receive power evenly, which in turn, provide the power to the capacitors. My point is that nobody has to even follow this tutorial when they can simply do this, for one, you wouldn't have to destroy a perfectly good circuit board, and two, this way also allows you to use ANY KIND of circuit board as long as each one uses the same power source. Lastly, why would you want to waste so much money on building the guns body and/or case, when you can simply use the body of your choice water gun, nerf gun, etc. The inside of one is bound to have enough space to hold everything, and you can paint it the color of your choice when you finish putting it all together. That way it can save you the hastle on buying, finding, wasting much MORE money on the things to make one.
<p>There's actually a very good reason you don't connect he boards and caps in series, that is because they wont balance correctly. Each cap has a different capacitance, it can be off by only a few microfarad or off by hundreds of microfarad, regardless, if you put them in series, the lowest value capacitor will stop charging first, and current will cease to flow through the loop at that point. (findamental property of a capacitor is that it stops allowing current to flow once it's charged) This is not a big problem if all your caps are almost identical, because you will get pretty close to the correct voltage on each capacitor. But if you're using cheapo disposable camera capacitors, then odds are your bank will stop charging long before every capacitor is fully charged. The solution is to use an active balancing solution, or a microcontroler, that systematically monitors the voltage of each cap and drains and charges them as needed to maintain balance. But that is an expensive and involved solution, the better method is to put them in parallel. <br>Further, you dont gain any power when putting them in series over parallel</p>
<p>the soloution to this problem (caps in serial unbalanced) is to use the voltage divider principle. just put on each cap a low-tolerance reisistor in parallel. This will make sure that each capacitor will be charged. Please google the math for the right resistors.</p>
<p>i am in a country that dont have exactly that cameras :P soo i cant easy make this and i need to know WICH coil-magnet wire i need can someone pls send a link to me? &lt;3 thank you </p>
i also wanna give thanks to instuctables user Plasmana. without his idea on his worlds smallest electronic shocker, i wouldnt have been able to use this idea for the coil gun charging circuit, and have been able to decifer rwilsford07's method.
for those of you who want to know EXACTLY on what connects to what using rwilsford07's technique, i drew up a diagram that'll make it much easier to understand. this way will also allow you to once again, use ANY curcuit board as long as it has all the correct componants shown in the diagram. the best thing about this diagram, if your a experienced solderer, you can desolder the components and solder them together OFF the curcuit board, which is best because it'll allow you to save A WHOLE LOT of space within your coil gun.
Why not just connect the circuit boards in series instead of in parallel, so each board can receive power evenly, and without having to cut out ANYTHING as well. You can make a simple cheap coil gun from a single camera circuit board without having to or cut anything.
<p>how to manualy connect a kodak ( disposeable camera ) transformer to wires to connect to the transformer and get high voltage?</p>
<p>I'm not sure for that application, but I made a taser like that.</p>
<p>Did u actually brand it with FESys</p>
<p>Does this work?!?!?!</p>
<p>how many batteries do i need?</p>
rwilsford07, may i ask your email?
<p>hi uh what kind of capacitor did you use i' new to this so i'm not really sure, i know it isn't a super/ultra capacitor but if you could give me a link to a similar capacitor to the one used in this instructable that would be helpful thanks</p>
<p>I think I'll try this project this weekend.</p>
I have got myself two types of disposable cameras (FUJIFILM and Polaroid). <br>I can't tell where to cut the circuit board (and what the transformer looks like) so that the transformer comes out. <br>If It's not too much trouble could someone draw on the photos where I need to cut. <br>Thanks.
The circuit board with the red LED. Do I need to cut it with the Transformer?
When you say the capacitors should be rated 300VDC...<br>Do you mean each capacitor or all the capacitors in the bank must equal 300VDC to 900vdc?
Each capacitor.
the design bears striking similarity to that of a high power emp device, will the gun emit an emp pulse when fired? http://www.wikihow.com/Build-an-EMP-Generator - (link to wikihow that shows how an emp device is created)
Where else can I get charger circuits from? A lot of the stores nearby me are not that generous.
I'm willing to bet you get better picture quality with one of those kodaks.
Hey,I'm use circuit disposable fujifilm,how to make it into parallel ? <br>
So I am looking at the semi automatic design, and I was wondering what exactly the injector solenoid did? Also if I used the &quot;Boost Converter&quot; that he also shows you how to build would you need the disposable cameras?
In reply to ishmal1103: <br>It's possible you've heated a transistor too much and it has burned out just replace every transistor but be quick and make sure it doesn't get too hot again or it will blow one of them out and then you will have to replace all of them again because you can't tell which one is the dead one (make sure when you get a new transistor its matches the one on the circuit board or it wont work e.g. the circuit board one might be negative positive negative (npn) so you will need to get a npn and not a positive negative positive (pnp) you can search up how to test between the two.