Coilgun Handgun

Coilgun Handgun
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Learn how to make a simple but extremely effective Coil gun using only a "few" parts that are fairly easy to obtain by only going to a few places and possibly online. 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!!!!!!'

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( 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
-Solder
-Flux( Not necessary, but it does help)
-Super Glue/ Epoxy/ Hot Glue(Used for gun casing)

Tools
-Solderer
-Pliers
-Wire Cutters
-Wire Stripper( A big help)
-Scissors
-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!.

My Web Page: Future Experimental Systems
Go to see all the coilguns and railguns

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

Read All Instruction before getting supplies (Especially second to Last Page), Research on pricing is recommended and I would recommend buying online or at a surplus store and not Radio Shack, Unless your impatient like me.

This simulator is about 30% accurate on average and is a great design tool for you to use, it has some issues but once you get the hang of it it is very useful:
Very Useful Coil Gun Simulator
Experimental research shows that as the magnetic flux increases above 4-5 Tesla the actual efficiency dies off dramatically, which is not shown in the simulator.

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 best navigation and organization.
- GoldmineGreat prices on useful parts
- Digikey Good for hard to find parts and best customer service and shipment speed.
- 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

NEED CAPACITORS CHEAP? HAVE A PAYPAL ACCOUNT? LET ME KNOW, I have hundreds of photoflash capacitors just sitting around, help me find them a home.
All funds go toward my SVPAR-1 coilgun super rifle, let's make the world a safer place.
 
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Step 1Charger Circuits

Charger Circuits
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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) or mind) 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. Post the number and type of the batteries you want to use and I give you a guesstimate on how many chargers you'll need.

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 other chargers as shown in the picture diagram. I do not recommend putting the chargers in series, so don't worry about it.
If you need to charge a capacitor bank above 500V view my DC-DC converter and let me know your requirements and I will give you the part numbers you'll need.

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.

USE THE CAMERA CIRCUITS IN THE PHOTOS BECAUSE THEY WORK THE BEST, they are from Kodak cameras. Most other circuits only work at 1.5V max and will only put out a max of around 250V.

Camera circuits are mostly inefficient i.e. 16% by my testing, if you want your gun to charge faster and with less battery drain build 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

TEST EACH CHARGER INDIVIDUALLY BEFORE YOU PUT THEM INTO A BANK

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.
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2893 comments
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Jan 14, 2012. 10:19 AMurmit says:
hello, I am fairly new to making this coilgun so I have a question. I have 12 capacitors, and 8 AA batteries (in a holder from RadioShack). So how many chargers do I need to use?
Dec 25, 2011. 7:40 PMR.A.T.M says:
do i have to cut down the charger circts or can i hook them normaly up in parralel
Oct 7, 2011. 4:14 PMtinker234 says:
thought could i magneticly suspend the bullet so that way there is no friction on the projectile
Dec 8, 2011. 12:55 AMjalvarado-3 says:
I got a roll of magnetic tape, could you place that above the straw so it draws the metal projectile up a little, effectively reducing its weight. I dont know, havent built one yet, just wondering
Dec 6, 2011. 9:07 PMbodacioushammer says:
I have been following your extensive guide and have been able to make a fairly simple design. since i am not shooting for anything fancy i am working with the bare minimum. I am using a 20 AWG magnetic coil with 4 layers and a Gauge wire linking everything together. I have 8 capacitors in my bank. I can get a big charge, but i cannot get it to pass through to the coil. does the wire have to be the same gauge as the coil? or do i need more layers on my coil to make it work?
Dec 4, 2011. 7:32 AMbjohnson45 says:
can i replace the straw with PVC pipe?
Nov 28, 2011. 9:02 AMRedIrishman says:
This is one of the best "rail guns" I've seen, love the casing. Have you thought about adding more coil, cap and flasher circuit stages to it? You'll get a lot more velocity out of the projectile and overall fps. You could use hall effect transistors or photo transistors, but you'd have to use SCRs, MOSFETS, or High current transis tors as relays wouldn't switch fast enough. Just an idea. but it would probably be a riffle at that point. lol
Nov 30, 2011. 10:28 PMrmccollum says:
whats wrong with a rifle at that point it would be stronger and have an actual practical use even military use possibly
Nov 27, 2011. 10:56 PMOgmoe says:
Very nice! I'm really impressed by the plastic casing on the PA-III-B. How did you make it?
Nov 22, 2011. 2:11 PMHav0c says:
if you use metal washers when winding the coil do you have to take them off after or can you leave them on for strength.
Nov 18, 2011. 6:15 PMIwantbigboom says:
How much did it cost to buld for the paiiib model,and what model does this inst'
show how to make?
Oct 23, 2011. 2:36 PMBrunoG says:
Why not use a microwave capacitor they have high capacitance and a lot of voltage.
Nov 17, 2011. 10:14 PMjj.inc says:
They are AC, they would work, but you get half the capacitance that they say they have.
Nov 17, 2011. 5:04 PMbbobbson says:
How many chargers will I need for a coil gun using 10 9v batteries?
Nov 15, 2011. 3:52 PMIwantbigboom says:
How much did it cost to build?
Nov 2, 2011. 7:50 AMjalke116 says:
Good day!!!
I just want to know if What software are you using in making your digital schematics?
Oct 9, 2011. 6:15 PMkurtiggler says:
the charger circuit in the cameras i have appear to be slightly different, i am having trouble relating the one in the pictures with the ones i have. there is no diode above the transistor, there are two much below it, unfortunately i have already cut out the corner as in the picture.

if someone could help me that would be much appreciated
018.JPG
Aug 21, 2011. 11:41 AMngunarathne says:
why not use a good 'ol neodymium magnet as a "hammer" that goes thru the coil and strikes a non-ferromagnetic projectile? that would eliminate any back firing effect and you wouldn't even have to time when the coil goes off. right?
Oct 7, 2011. 4:10 PMtinker234 says:
wow thanks i will try this when i make one
Oct 7, 2011. 4:02 PMtinker234 says:
what if i used a cell phone battery and had it in the handle when emtpy i can just plug it in
Oct 7, 2011. 7:03 AMlightfiredark94 says:
Cool website bro.
Jul 13, 2011. 11:21 PMpopomaster says:
What is the purpose of the transformer in the charger circuit? Doesn't the 3v input build up in the capacitors to the desired amount? Is it to reduce the voltage when the capacitors release the current through the coils and back through the charger circuit? Im sorry if it's a newbish question. If the question is too hard to understand than a diagram (or step by step) of the flow of electricity through the circuit would be nice. Im just so confused on how the circuit work detached from the main board with the new connections and the ground wires and crap. Thanks
Sep 22, 2011. 7:18 PMd3monhax0r says:
if you just connect 3v to the capacitors, it will ONLY charge to 3v.
the transformer is part of the charging circuit, which will charge it ( so it can reach the limit of the capacitor)
Sep 1, 2011. 8:56 AMcrissangelic says:
how would you test the charger
Sep 22, 2011. 7:13 PMd3monhax0r says:
connect it to the capacitors to see if it charges...
Sep 9, 2011. 4:18 PMlord voldamort says:
i have 16 cameras, how could i get the most out of them? thank you
Sep 22, 2011. 7:12 PMd3monhax0r says:
put capacitors in parallel
put charging circuits in parallel
keep AA batts
Jun 6, 2011. 9:01 AMPyro Fiend says:
What if I used a 2600F capacitor at 2.5V.
Would this work?????????????
Sep 21, 2011. 1:39 PMd3monhax0r says:
no... much more voltage is needed
Sep 1, 2011. 6:17 PMzwells says:
can you give me the blue prints
Sep 1, 2011. 9:30 AMcrissangelic says:
in the first diagram you show a "charging switch" but in the second there isn't one is the switch necessary
Aug 31, 2011. 1:48 PMcrissangelic says:
so i made a coil 40mm long with 6 layers when i connect a battery to both ends i see sparks at the + side but it is not magnetic did i do something wrong
Aug 31, 2011. 8:20 AMcrissangelic says:
is using a short (4 inch) coil more effective than a longer (1 foot) coil
Aug 31, 2011. 7:59 AMcrissangelic says:
how many camera circuits would you recommend
Aug 21, 2011. 6:35 PMrocket_man says:
I have a question that am pretty sure most ppl that see this instructable could answer http://www.instructables.com/answers/make-a-camera-circuit-only-charge-to-200Vs/
Nov 8, 2009. 4:49 PMEkzile says:
 Is it possible to make one semi-auto or even fully auto? Or does it need to charge before every shot?
Aug 21, 2011. 5:42 PMLeelaKrishna says:
you would have to have different sets of capacitor banks .
for every shot without wait would take that many capacitor banks
Jul 13, 2011. 7:52 PMjbrueggeman says:
It would be semi-auto with this design, however the second shot would need time to charge the capacitors before you got any real distance out of it. Automatic would require straight raw power instead of charging a capacitor bank, in which, the setup here would be fairly useless. If you're thinking about automatic, your best bet would be to try and amplify the current, which would require heavier gauge wires and most certainly would be much more expensive, heavier, and less mobile. Besides, unloading automatically is extremely unnecessary. The only reason to fire anything automatic is in war. Anywhere else, semi-auto is more than enough.
Dec 8, 2011. 12:57 AMjalvarado-3 says:
Could you build two+ banks of capacitors that all get charged but each shot only uses one bank, then next shot uses another bank etc, when all the while, the previous capacitor banks are being charged?
Aug 5, 2011. 12:42 PM_Scratch_ says:
For full auto, just have dual or quad, depending on the rate of fire, that change each shot. So while the recently fired cap bank charges, you fire from another bank. It would be rather bulky, and far more expensive, but not that much harder to do.
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Author:rwilsford07(Future Experimental Systems)