coilgun handgun

7/27/2019 Coilgun Handgun

1/21

http://www.instructables.com/id/Coilgun-Handgun/

Home Sign Up! Explore Community Submit

All Art Craft Food Games Green Home Kids Life Music Offbeat Outdoors Pets Photo Ride Science Tech

Coilgun Handgunby rwilsford07 on November 13, 2007

Table of Contents

License: Attribution Non-commercial Share Alike (by-nc-sa) .............................................................................

Intro: Coilgun Handgun ........................................................................................................

step 1: Charger Circuits ........................................................................................................

step 2: General Details ........................................................................................................

step 3: Coils, Capacitors, and Results ............................................................................................. 1

step 4: Bring It All Together ..................................................................................................... 1

step 5: Projectiles ............................................................................................................ 1

step 6: Coilgun Research and General Information .................................................................................... 1

step 7: Updates .............................................................................................................. 1

Related Instructables ........................................................................................................... 1

Advertisements ............................................................................................................... 1

Comments ................................................................................................................... 1
http://www.instructables.com/member/rwilsford07/?utm_source=pdf&utm_campaign=titlehttp://www.instructables.com/tech?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/science?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/ride?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/photography?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/pets?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/outdoors?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/offbeat?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/music?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/life?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/kids?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/home?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/green?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/games?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/food?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/craft?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/art?utm_source=pdf&utm_campaign=categorieshttp://www.instructables.com/about/submit.jsp?utm_source=pdf&utm_campaign=titlehttp://www.instructables.com/community?utm_source=pdf&utm_campaign=titlehttp://www.instructables.com/tag/type-id/?utm_source=pdf&utm_campaign=titlehttp://www.instructables.com/account/gopro?sourcea=inside_pdfhttp://www.instructables.com/?utm_source=pdf&utm_campaign=title


2/21


License: Attribution Non-commercial Share Alike (by-nc-sa)

Intro: Coilgun HandgunLearn 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. BWilling 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 f irst one in only a week af ter I had athe parts.

Coilgun Principal:Coilguns(Pulse Accelerators), like railguns(Linear Accelerators), use intense electromagnetic fields to propel objects at incredible velocities unreachable with modern 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 aferromagnetic(magnetically affected) projectile, in this case a shaped steel round, toward its center. Ideally the current supporting the electromagnetic field will turn offwhen 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 understthe 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 asingle 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 toflow.

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 intothe 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'sefficiency)-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 differentstore 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 ancurrent 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 providsubstantially 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 batteryratios.

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 forused 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 willfaster 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 SystemsGo 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 surpstore and not Radio Shack, Unless your impatient like me.
http://www.coilgun.ru/http://futureexperimentalsystems.googlepages.com/http://www.radioshack.com/http://users.skynet.be/BillsPage/MassAccelerators.htmlhttp://creativecommons.org/licenses/by-nc-sa/2.5/


3/21


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 useVery Useful Coil Gun SimulatorExperimental 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- Goldmine Great 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 the

home.All funds go toward my SVPAR-1 coilgun super rifle, let's make the world a safer place.

Image Notes1. PA-III-B Completed

Image Notes1. PA-III-B Before Completion

Image Notes1. Finished PAR-I
http://www.alltronics.com/cgi-bin/category.cgi?category=0http://www.surplussales.com/index.htmlhttp://theelectrostore.com/shopsite_sc/store/html/capacitors.htmlhttp://www.mpja.com/default.asphttp://search.digikey.com/scripts/DkSearch/dksus.dll?site=us;lang=enhttp://www.goldmine-elec.com/http://www.mouser.com/http://www.gausspistol.com/Simulator.html


4/21


Image Notes1. Permenant internal relay power supply2. Integrated laser sight3. Internal LED Flashlight4. Ammunition clip5. LED Flashlight/LASER switch6. Bolt Action7. Single 400V 470uF Capacitor8. ON/OFF9. Before Completion PAR-1

Image Notes1. Tools

Image Notes1. Charger Circuits2. Capacitor Bank3. 22 AWG Coil, 8 Layers, 30mm Long4. Relay5. Relay Power Source, 4*9V Batteries, later replaced with one 9V6. 2 AA Battery Holder, One on Each Side Of Gun to power two Charger Circuits.7. Unsupported Barrel, Was Later Supported by Vertical Panes of Plexiglass8. This was my first coilgun, I have since inproved greatly on it's design as well asothers. I keep it on here to show how I started.

Image Notes1. 6.8mm Round Entry and Exit2. Exit Pattern


5/21


Image Notes1. CLICK THE "i" FOR THE ORIGINAL (Legible) SIZE

step 1:Charger CircuitsThe 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 centerplastic 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 ofheart(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 i t, 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 thechargers 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 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 recommenputting 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 anddiode)(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 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 .
http://www.instructables.com/id/DC-DC-HV-Boost-Converter/


6/21


7/21


Image Notes1. Multiple Finished Mini Chargers2. Transformer3. Transistor4. LED5. Diode

Image Notes1. 8 Charger Bank In Parallel2. HV Negative Out3. Positive Input Wire (3V to be safe) Using a higher voltage may destroy yourcircuits.4. Negative In and HV Positive Out5. Electric Tape for insulation between Circuits6. Double layer Insulation Tape to prevent shorts.

Image Notes1. Input Wires2. - Input Negative3. + Input Positive (3V max for safety. Use more at your own risk.)4. Output Wires5. ++ High Voltage Positive 500V at 3V input6. -- High Voltage Negative Output7. Transformer8. Transistor

9. LED10. Diode11. Connection Wire12. Single Lead From Circuit Split into two.13. SMT (Surface Mounted) Resistor


8/21


step 2:General DetailsCapacitors:Connect the capacitors Via bare Solid wire and solder( Line up the negative with the negative!).The capacitors should be rated 300VDC to 900VDC for best results, I recommend energy levels below 200J per stage or below 2000uF. The energy found in a capacican be calculated based on this formula:

1/2 x C x 1e-6 x V2

or

0.000005 x C x V x V

Where C is the capacitance in micro-farads (uF) and V is the Voltage the capacitor is charged to in Volts.

Coil:

Using the simulator or the previously test coils on step 3 determine your coil dimensions, gather the following supplies.

Here is a good video that shows you how to wind your coil:How to Wind a Coil

-Bolt of an appropriate length and diameter-Large diameter washers and nut to fit on the Bolt-Electrical(usually black) tape or preferably super glue or epoxy-Straw or paper to create a space between coil winding and the bolt-Magnetic or Enamel wire-I use Plexiglas( which can be found at Lowes or Home Depot) washers created via a hole saw and drill press. This allows you to super glue each layer to the plasticwashers that way the coil is much more structurally sound when taken off the coil. If you choose to have plastic washer you can feed the starting wire through a grovehole cut in back plastic washer, this aids greatly in winding.

Now, get your straw or piece of paper and cut it about 1-2mm longer than the desired length of your coil. Put the end washer(s) on the bolt and place the straw or papon the bolt as shown in the picture, if the straw doesn't fit on the bolt simply cut it length wise.fit the remaining washer and nut on the bolt as shown.

Now feed the end of your magnetic wire though the center of your end washer and allow about 2-3 in of the wire to come out the other side. Wrap the wire that was puthrough the end bolt around the head of the bolt to secure it in place. Now start to wind the coil in a clockwise or counter-clockwise manner around the bolt. DO NOTswitch from counter-clockwise to clockwise or vise versa, always wind in one direction around the bolt., otherwise your coil will not work .Continue to wind until you hreached the other end, secure the wire wi th your thumb and if you have tape tap the layer down tightly, if you are using super glue DO NOT glue the first layer, this wiglue the wire to the straw or paper.To make a second layer simply continue to wind, rotating in the same direction you started and making you way back to the other end of the coil on top of the first layeOnce you have reached the other side glue or tape the assembly and continue to wind in the same clockwise or counter-clockwise direction back and forth along thelength of the coil. Wind the coil as perfectly as humanly possible and keep the wire as perpendicular to the bolt as possible.

Once you are done with your coil tape or glue the assembly as tight as possible and let it sit for few hours. Then, take the coil off the winder as carefully as possible anremove the inside of the straw or paper with pliers.

To Make the Guns grip open the plastic handle and hot glue in the roller switch so that the switch is triggered by, well, the trigger. Drill holes in the back and attach wirto the switch (1,3) and then put the wires through the holes. Close the Handle and if you can hear a click when you pull the trigger it should work.

RELAYA relay has two working elements in it, an electromagnet and a mobile contact.First a little Vocab:

NC-Normally Closed-When no current is applied to the electromagnet C and NC are connectedNO-Normally Open-When current is applied to the electromagnet C and NO are connectedC-Common- Connected to either NC or NO based on state of electromagnetSPST- Single Pole Single Throw- Either NC or NO is included in this relay, not bothThis relay will have 4 connections, Although some appear to have more, If the location of the electromagnet is unknown apply a 9V-12V source to each connectioncombination possible until a click is heard, this is the electromagnetic and when the relay is hooked up as in the diagram in the subsequent step the gun will fire when proper voltage is applied to these connections once more.SPDT- Single Pole Double Throw- Both NC and NO are included in this relay(Shown in Picture below)This relay will have 5 connections, Again If the location of the electromagnet is unknown apply a 9V-12V source to each connection combination possible until a click iheard, this is the electromagnet and when the relay is hooked up as in the diagram in the subsequent step the gun will fire when a proper voltage is applied to theseconnections once more.

For this Project either a SPST or SPDT Relay can be used, we only use the C and NO connection so a SPDT will have an unconnected Lead.

Opening the Relay will allow you to find these connections much more quickly, but put the cover back on when your ready to install the relay.

Also Below is a picture of the semiautomatic configuration in my PA-III-B.
http://www.youtube.com/watch?v=547hM79Y3Vg


9/21


Image Notes1. You can place Plexiglas washers inside the steel washers and super glueeach layer to them to get a better made coil.2. grove put in washer to fit the initial wire.

Image Notes1. Straw on Bolt2. Wire through grove3. Nice!

Image Notes1. Finished Coil2. Wind Your Coil as Perfectly as you can.3. You can also use Plexiglas washers to aid in winding the coil as well as givethe coil extra structure when taken off the winder.

Image Notes1. Capacitor Leads Connected2. Negative Side Has Stripe3. An Example of a capacitor bank

Image Notes


10/21


1. Trigger Switch2. Leads to be Place on Outside

Image Notes1. Spring Return2. Nylon Injection Pin3. Nylon Injection pin glued into 1/2in Bolt armature4. 1/2in Bolt(Armature), this is the device that is pulled into the injection solenoidand therefore pushes the projectile into the Optical Sensor which fires thePrimary Accelerator Coil.5. Rear Support, The Injection Solenoid is very powerful and must be fitted to thstructure very strongly.6. Injection Solenoid, 20-40 Layers, 26-30 gauge wire, 20-30 mm Length7. Ammunition Magazine/Clip8. Projectile9. Primary Accelerator Coil Support: This Support must be fitted to the CoilgunStructure as rigid as Possible.10. Optical Sensor, Senses the Projectile and Fires the Primary Acceleration Co

A contact Sensor may Also be Used Here.11. Primary Accelerator Coil: I did not use a barrel inside the coil so that the coiland the projectile would be as close to each other as possible. A thin layer ofsuperglue inside the coil was used to protect the coil from damage.12. A Barrel was fitted to the front of the Primary Accelerator Coil's Structure inorder to guide the Projectile out of the gun.13. Plexiglas Washers: 5mm14. Please Click on the i to the left to view the full size diagram.

step 3:Coils, Capacitors, and ResultsCoils, Capacitors, and ResultsAll measurement are taken from velocity test with chronograph and are maximum achieved.

22 gauge:-UM:7 Layer, 33mm L, 6.5mm InDia 1320uF 330V E.37m/s 4g(11*330V 120uF)

-8 Layer, 30mm L, 8mm InDia 960uF 350V 24m/s 8g(8*330V 120uF) 3.9%-12 Layer, 30mm L, 8mm InDia 600uF 350V 12m/s 8g(5*330V 120uF) 1.57%-12 Layer, 30mm L, 8mm InDia 470uF 450V 27m/s 8g(1*400V 470uF) 6.1%-16 Layer, 30mm L, 8mm InDia 470uF 450V 28m/s 8g(1*400V 470uF) ****Best results 6.6%-UM:12 Layer, 30mm L, 8mm InDia 470uF 800V E.>50m/s 8g(4*400V 470uF)

20 gauge:-UM:12 Layer, 29mm L, 8mm InDia 940uF 400V 31m/s 8g(2*400V 470uf)-UM:12 Layer, 12mm L, 8mm InDia 1200uF 350V 26m/s 8g(10*330V 120uf)-8 Layer, 12mm L, 8mm InDia 880uF 450V 13m/s 9.0g(4*400V 220uF)-Ferrite Surrounded-8 Layer, 12mm L, 8mm InDia 880uF 450V 14m/s 9.0g(4*400V 220uF)-8 Layer, 30mm L, 8mm InDia 1100uF 450V 33.0m/s 9.0g(5*400V 220uF) SCR Switched 4.4%

E.=Estimated Velocity-The velocity here is estimated based on visual comparison to the other results, they are Not measured.UM=Unmaximized- Coil not experimented with to achieve maximum results

If you do not have access to a chronograph the method HERE is relatively accurate.If you use this method to get velocity results make sure your coil is perfectly horizontal and don't fire to the ground, fire at a piece of foam that is a meter or so away.

Also HERE is an optical velocity measurement set up. I have not done it my self so I do not know how accurate it is.

Even at best the shown results are + or - 20% correct, this is because most electrolytic capacitors capacitance rating is within the + or - 20% region. In ordto get the results above you may have to test several different capacitors to match whatever value mine might have actually been.

My projectiles and speed measurements are close to 100% accurate so + or - 20% is the maximum offset.
http://rp181.110mb.com/index.php?p=1_24http://www.coilgun.eclipse.co.uk/projectile_speed_measurement.html


11/21


step 4:Bring It All TogetherNow Connect Everything Together. Follow the Picture Diagram and Schematic.

Test the system, if it works use Plexiglas, wood, or even metal (avoid this) to make housing for your gun depending on the desired size/weight etc.

Let Me Know If you I can Improve this page.

The Battery Banks Must not exceed +3V for safe operation.

Image Notes1. Coil2. Relay3. 9V-12V( N )4. Fire Switch5. Capacitor Bank6. Charger Circuit Bank


12/21


Image Notes1. !Charge Switch Must be turned OFF before firing!2. Check Data sheet for SCR Pin Outs

step 5:ProjectilesProjectile Material:

The projectile material is the MOST IMPORTANT part of your coilgun system, I won't go into detail here but it determines probably 80% of how your coilgun will perfor-Basically your projectile must be ferromagnetic, i.e contain mostly Iron, Nickle or Cobalt.-It must be magnetically soft, which means that if a magnetic field is applied to it the material will not stay magnetized.-It must have the highest magnetic saturation point possible

The Best Materials I know of are listed below from best down:

Nickle-Cobalt

Nickle-IronPure Iron >$100Low Carbon Steel (Steel with a rating of 10XX where XX is the lowest number possible, such as 1006)Stainless Steel - Most stainless steal is NOT ferromagnetic, it must contain at least 80% Iron to be considered ferromagnetic.

Round Low Carbon Steel 1006 from McMaster-Carr will be the best material I found for your projectiles for a reasonable cost and availability. It is the lowest carbon stI could find for "low quantity" purchasing.

If you want efficiency in your coilgun but don't have the tools, time, or effort to make your own projectiles buy HERE , you can customize your rod cuts for a considerablow price and you don't have to do the tedious work, and the steel is low carbon, which means higher iron content and more efficiency. Also they sell acrylic for mycasings, which is a plus.

Projectile Fabrication

Now this is the "Hardest" and most t ime consuming part. In order to make the projectiles, cut the heads off of the nails using a Dremel tool with a reinforced cutting dis(will wear quickly) or a large grinder with a cutting blade.You can also use a hacksaw with a steel cutting blade, credit for this idea goes to memberjondo huang, I never even thought of it. This is the preferred method as it icheaper and the cut is much better.

Then cut the rest of the nail to the correct length ( They should be 3/4 to 5/4 the length of the coil). If you are looking for efficiency, i.e. velocity, simply grind the edges the projectile to a rounded flat surface and not pointed.Mine are sharp so they can do more damage. In order to do this I placed the projectiles in a drill press and used the grinder to grind the edges down, if you use theDremel you can get a smoother finish and finer point. This can be a long process, but well worth it.

You can glue smaller diameter straws to the end of the rounds to stabilize them, usually the longer the round, the longer the stabilizer will have to be.
http://www.onlinemetals.com/merchant.cfm?id=198&step=2http://www.mcmaster.com/#steel/=2v5xcv


13/21


Image Notes1. Used to make perfectly round tips

Image Notes1. Grinder2. Used to hold nails in place while cutting3. Dremel

Image Notes1. Round Blank2. Shaped3. completed

Image Notes1. Different caliber Ammunition

step 6:Coilgun Research and General InformationShoot cans, tins, or whatever your heart desires.(With the exception of others, unless they deserve it, not really). I am not responsible for you being stupid with this, Ifmade right you could seriously injure or Kill someone with this.

Experiment with a different amount of capacitors to maximize the Muzzle Energy.

Equations:

-Potential Energy=(1/2)(capacitance in uF/1,000,000)(voltage in V)2-Kinetic Energy= (1/2)(mass in g/1,000)(velocity in m/s)2

Equations for Capacitors in Parallel-Capacitance(C) total=(C of 1st capacitor)+(C of 2nd Capacitor)+...-Voltage(V)max= Lowest rated Voltage

Equations for Capacitors in Series-1/(Capacitance(C) total)=1/(C of 1st capacitor)+1/(C of 2nd Capacitor)+...-Voltage(V) max=(V of 1st capacitor)+(V of 2nd Capacitor)+...

-Power=(V)(I)

I-CurrentV-VoltageC-Capacitance


14/21


IDEAS POSTED HERE MAY BE OUT OF DATE (4/28/08)

Key Things to Know:I would recommend reading "all" of the following as a good understanding of system maximization is key to build a worthy gun. Some Very general characteristics to hyou create and maximize one are as follows.

A Few Variables

(These statements assume all other variables are unchanged and are as simply put as possible)(Maximization is reached at the greatest efficiency)

(These are SUPER Generalized statements and are Approximate (in reality there are many, many more factors). But these statements do provide a simplerunderstanding of the system.)

-The coil :

-The larger the wire diameter and the fewer layers it has the more Capacitance is needed to maximize it.-The smaller the wire diameter and the more layers it has the less Capacitacne is needed to maximize it.-The shorter a coil is, a shorter pulse time is needed for maximization, Therefore more layers for shorter coils is required for maximization resulting in a lower maximizcapacitance and a faster pulse time.-The longer a coil is, a longer pulse time is needed for maximization, Therefore fewer layers for longer coils is required for maximization resulting in a higher maximizincapacitance and a slower pulse time.-18-22 guage magnetic wire and 30mm Length seems to be a common place in most guns.

Capacitance :

(Discharge time constant(discharge to 37%) is determined by the product of capacitance and resistance) t=RC(for a simple RC circuit)

-A larger Capacitance has a longer pulse time and therefore affects the projectile a longer amount of time and so longer or heavier projectiles are needed formaximization.-A smaller Capacitance has a shorter pulse time and therefore affects the projectile a shorter amount of time and so shorter or lighter projectiles are needed formaximization.-The pulse time also relates to the length of the coil, a longer pulse time will be nessesary for a longer coil and a shorter pulse time will be necessary for a shorter coil.

...Take a Breath...

Voltage :

-There is a point where Higher voltage will taper off the output energy of the gun through power dissipated through heat. Power loss=I2*R (where I is current and R issystem resistance)-As far as I know an Increase in Voltage provides an increase in the output of the coil gun, to a point. That point is reached when the dV/dT (Change in voltage overchange in Time) is significant enough to produce a large amount of eddy currents.-Through research and experimentation it seems the best voltage range lies in the range of 200V to 800V, reason being 200V is a low enough voltage to where the wineeded to discharge the same amount of energy is significantly larger, which reduces the current density and increases the coil cost and size. The Upper limit of 800Vdue to the higher dV/dT which results in large eddy current losses, experiments with 900V capacitor banks show significant (ie the firing of non-metallic projectiles viaeddy currents) eddy current losses.-In general I recommend using 50J per stage for 200V banks and 200J per stage for 900V.(These are vague at best, but the limits produce better results)

Projectile :

-Ferromagnetic (objects which can be attracted by a magnet but not perminantly magnetized) material is what your projectile should be made of. I use large galvinizedsteel nails cut to size. Usually the nails will flip through the air, but if you attach a straw on the back the projectile will be stabilized (The longer the projectile the longer stabilizing straw must be)-Greatest effeciency according to projectile length can be reach with experimentation, but in general a projectile the length of the coil and as snug fitting as possible wiyield close to maximized projectile deminsions.-Smaller nails, screws, or even sling shot ammo can be used if power tools are unaccessable to you, but you will not get much effeciency with them, expecially spherprojectiles.

System Resistance :

I am still in the process of simplifing this as many factors in coilgun performance relates to resistance.

-Resistance is ultimately the defining aspect of a coilguns maximization. Many think that less resistance is always better, but this is not always the case. The fact thatresistance is indirectly related to current (I(current)=V/R) and a greater current produces a greater magnetic field; this points to less resistance and more current for agreater projectile acceleration. Although this is true, resistance also plays a direct role in pulse time, which determines the amount of time the capacitor takes todischarge, and the amount of time the projectile is under acceleration.-In conclusion one can say the higher the resistance, the longer the pulse time and lower the ampere peak; the lower the resistance the shorter the pulse time and higthe amperage peak.

-Also, with very low resistance ringing occurs in the system due to the coils inductance, resulting in the possible need for a protection diode reverse and parallel to thecoil, resulting in a much longer pulse time and current leakage through the diode.(see topic below)-will be continued...

Protection Diode :

-Many coilguns use a protection diode to prevent back emf(high reverse voltage that results from the coils induction) and to prevent system and capacitor failure. I didresearch with and without diode protection and the results explain the higher efficiency which my coils have been operating at compared to other much more advancemultistage guns. Experimentation showed an average of around 1/4 velocity loss wi th a reverse diode compared to no diode protection. As of now no damage has beedone to the capacitors or any circuits due to back emf. I will continue to do testing.

I may be wrong on some, or all, of this. : )

USE THE SIMULATOR ON THE FIRST PAGE FOR YOUR APPLICATION

DisclaimerI take no responsibility for your actions. If you shoot, shock, or otherwise injure yourself or others, Your


15/21


On Your Own.

Ideas, Comments, Questions? POST

Image Notes1. 6.8mm Round Entry and Exit2. Exit Pattern

step 7:UpdatesNews:-The clip spring for my new rifle was completed and works properly, for the most part. 11/17/07-Drilling through the back of the rounds proved a hard task and did not result in stabilizing the round completely, although it did mildly improve accuracy and velocity(Lof mass). 11/16/07-I just got a Velocity Chronograph to experiment more accurately with maximizing velocity.(Unfortunately it only works in sunlight and I'm not home to often during theday; Progress will be slow) 11/18/07-Larger(C and D) Batteries provide the coil gun with a MUCH faster load time(Due to ampere increase) with the same amount of batteries. Used with 2 in series lined with others that are 2 in series via Parallel) 11/18/07-The general concept of more Charger Circuits for a curtain amount of Battery Power is flawed: I found that for every Battery Power there is a maximizing amount ofcircuit Boards to use but more batteries are always better unless you surpass the power rating of the charger circuits.( More research for different size Batter ies isneeded) 11/18/07-Surprisingly Faster Charge Systems leading to large automatic coil guns possible. Due to Battery Breakthroughs. 11/19/07-Solenoid that was bought doesn't contain a push back spring, new solenoid was found and will be installed shortly after arrival. (Another long wait for the main; whichalways seems to come right before work)-Next Generation Coilgun will be a multistage rifle due to research into contact triggers(Goal is 75m/s, Possibly automatic which seems a simpler task than semi-auto charge time is reduced significantly, I figure aim high)(HAMSEMLA I ).11/21/07-Final Research Design Before Rail gun research will be a multi barreled Mini gun type gun(Because it looks cool; O and it will allow the coils to cool betweenshots)11/24/07-Research into the maximization of the coil of EMILA II has lead to an interesting discovery, the Kinetic energy of the projectile is maximized (As well as efficiency) whthe projectile is the length of the Coil, while Velocity is maximized at about half the length of the coil. A worthy compromise between the two is a projectile at 3/4 thelength of the coil. 11/24/07-Placing a smaller straw at the ends of your projectile make them fly very straight, which although good, means that even flat headed rounds fly through two inch thickStyrofoam with ease. 11/24/07- In general, for a certain coil in specific conditions, the center of a round must be a certain distance from the center of the coil no matter how long the round is. Thismeans that for Larger Rounds, more placement inside the coil is needed, while smaller rounds require placement that may be outside the coil; eventually the small rouis too far outside the coil, significantly decreasing its energy taken from the coil in terms of Kinetic Energy.11/24/07- I experimented with a 12 layer coil(30mm Length) and some new capacitors(4 470uF 400 V). I used one 470uF 400 V capacitor and was able to more than match thevelocity of the 1080uF 380V handgun. Efficiency of this is the best so far. 12/3/07- I experimented later with the 12 layer coil and the new capacitors(4 470uF 400 V) I was able to align them to get 800 Volts at 470uF and was able to fire it around 8times before the charger circuit's transistors started smoking then exploded(I used 8 charger circuits with 16 C Batteries lined up to get 12 Volts and a 900 Volts outpualso used a wall transformer and it basically exploded from the demands of the Capacitors before using the batteries). The result was an extremely powerful coil gunwhich when fired pierced 1mm thick steel plate as well as an entire tin can. See pictures below. 12/3/07

- I have not been able to make much progress on the newer hand gun and the charger meltdown is a huge set back. I t will be a while till progress continues. 12/3/07- Charger circuit tests show that you can use up to 6 C cell batteries in a 3V configuration with one charger circuit without burning up the transistor, I would recommenusing just 2 per charger circuit, also using more charger circuits reduces resistance in the system and power capacity of the charging unit. 12/11/07-Charger circuit tests show that you must use 3 charger circuit for just 2 D batteries at 3V in order to not burn up the transistors. I would recommend using at least 6Chargers per 2 D batteries. 1/28/08-Reverse Diode Across coil- Every professionally made coilgun uses a "protection" diode across the coil to prevent back emf. Research was done pertaining to this maand a great deal of efficiency loss was examined. Several coils were tested and a average of about 1/4 of the velocity of the projectile was lost to the diodes prolonginthe electromagnetic field. More research will be done but as of now great efficiency may be due to the lack of diode in my system. Also tests with a high rated diodeconnecting the coil to the capacitor which allows current flow one way, prevents a prolonged field, and prevents reverse voltage from back emf will be tested as well asother means to prevent back emf. 2/20/08-Work on my new PA-III has been slow, but initial fi rings without maximization seem to put the gun as having great potential. The projectile ripped through a tin can ankept going until it suck in my drywall.-PA-III Main support structure, Ammunition casing, and Power source construction has been completed. Next will be the autoloader and possibly a reduction in totalstored energy as efficiency at high levels appears to dies of. A relationship between Increased voltage and Energy levels effect on efficiency will be mapped soon.-I have moved and extensive work on my new workshop will be needed until research and other projects can be continued. 07/01/08-Work on PA-III will be suspended until proper tools are accumulated again. 07/07/08-The PA-III was redesigned and subsequently named PA-III-B, I t is nearing completion and only requires painting as of now. Also previous research into camera circu


16/21


reveled that the number of camera circuits DOES NOT change the output of the circuits, but simply allows more power to flow through the them before failing. Theampere-hour rating , or capacity, however does directly relate to the output power, ie the more batteries you have in parallel (increasing capacity) the higher the outputhe camera circuits until the point to which the chargers fail. Once time allows a graphical representation and report will be completed and posted as a l ink, time howevis short so it may be a while. 11/11/08

Image Notes

1. New SDPA-1 Model

Image Notes1. Simple gun made on vacation (high velocity low mass)

Image Notes1. More Capacitors2. 400V 470uF Capacitors Bought at Electronic Goldmine for $2.

Related Instructables

My Mini Tazer(first solderedproject) (video)

by cowscankill

9 volt secret

taser by emorulz

Disposablecamera coilgun

by AlfonsVH

Cheap/freecapacitor bank

and charger by

n3ldan

20,000v Flyback

Transformer by

slipknot rules Electromagnetic

Floater by

J_Hodgie

MR-1.2 Coilgun(UPDATE: NEWINTERIORPICTURE)

(slideshow) by

mspark400

coilgun

blueprints by

eneergcam
http://www.instructables.com/member/eneergcam/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/coilgun-blueprints/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/coilgun-blueprints/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/coilgun-blueprints/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/member/mspark400/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/MR-12-Coilgun/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/MR-12-Coilgun/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/MR-12-Coilgun/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/MR-12-Coilgun/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/MR-12-Coilgun/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/MR-12-Coilgun/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/member/J_Hodgie/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Electromagnetic-Floater/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Electromagnetic-Floater/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Electromagnetic-Floater/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/member/slipknot%20rules/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/20000v-Flyback-Transformer/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/20000v-Flyback-Transformer/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/20000v-Flyback-Transformer/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/member/n3ldan/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Cheapfree-capacitor-bank-and-charger/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Cheapfree-capacitor-bank-and-charger/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Cheapfree-capacitor-bank-and-charger/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Cheapfree-capacitor-bank-and-charger/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/member/AlfonsVH/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Disposable-camera-coilgun/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Disposable-camera-coilgun/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/Disposable-camera-coilgun/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/member/emorulz/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/9_volt_secret_taser/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/9_volt_secret_taser/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/9_volt_secret_taser/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/member/cowscankill/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/My-Mini-Tazer-first-soldered-project/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/My-Mini-Tazer-first-soldered-project/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/My-Mini-Tazer-first-soldered-project/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/My-Mini-Tazer-first-soldered-project/?utm_source=pdf&utm_campaign=relatedhttp://www.instructables.com/id/My-Mini-Tazer-first-soldered-project/?utm_source=pdf&utm_campaign=related


17/21


vertisemets

Comments

50 comments Add Comment view all 2511 commen

Barrettkg says: Feb 10, 2010. 11:47 AM REPCan discharging your capacitor bank destroy capacitors?

Gladiater says: Feb 8, 2010. 12:31 PM REPoh and stupid as i am i forgot to ask one thing; that is how much chargers will i need? i've got alot of them from old disposables, but i dont know how muchuse really.

Gladiater says: Feb 8, 2010. 12:14 PM REPYeah, this is a great instructable, and i'm curious to see the APA-1 when finished. im building this too for a sience project and my exams kinda relie on thisso its a bit important hehe. but ive got 2 questions.1: lets say i use 4 400V 470uF caps is that enough power?and 2: i cant find any roll of spooling cable that has a clear coating longer than 23 metres :-/ . what would be better; If i roll a coil of this, 30 mm long 8 mmInDia and like, 9 layers or if i solder 2 together? i'm afraid soldering 2 together will give a huge loss of power, so much that the coil will become useless.any tips/help/hints?

moshee says: Feb 7, 2010. 1:59 PM REPHey rwilsford, is your project pretty much dead now?

eggman says: Feb 7, 2010. 2:42 PM REPi think he mentioned before that college was taking his time, but i have noticed that be basically stopped updating his site.

rwilsford07 says: Feb 7, 2010. 3:34 PM REPThe APA-1 Project is still alive, unfortunately I've had my free time full making power supplies and filling orders for others. The good news is I havemost of the parts, I just have to finish the current orders I'm working on first and hope no other orders come in.

moshee says: Feb 7, 2010. 5:30 PM REPWell, it's great to see you're actually making money for this. I'm really looking forward to seeing how this turns out.

eggman says: Feb 7, 2010. 4:17 PM REPawesome. i cant wait to see how that gun comes out.

skiz1989 says: Feb 1, 2010. 9:36 AM REPWhats the point of D1?.... is it to make sure the current will always flow one way?...or does it prevent "suck back"?

moshee says: Feb 7, 2010. 1:45 PM REPIt's to prevent "back EMF" which can damage the capacitors and possibly blow them up.

hunter566 says: Jan 31, 2010. 10:39 AM REPcan i use 220uF 400V capacitors and still get enought power to shoot omething a couple feet away

eggman says: Jan 31, 2010. 3:56 PM REPabsolutely. throw a few of those in parallel, and you've got yourself a formidable coilgun. depending on whats available to you, i'd aim for 5 or 6 ofthose capacitors in parallel.

hunter566 says: Feb 2, 2010. 3:23 PM REPif i used 7 how many cameras do you think i would need
http://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/hunter566/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/hunter566/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/hunter566/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/hunter566/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/moshee/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/moshee/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/skiz1989/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/skiz1989/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/moshee/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/moshee/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/rwilsford07/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/rwilsford07/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/moshee/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/moshee/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/Barrettkg/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/Barrettkg/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments&comments=all&sort=OLDEST#commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments&comments=all&sort=OLDEST#commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments&comments=all&sort=OLDEST#commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#comments


18/21


eggman says: Feb 2, 2010. 8:11 PM REPthat puts you at 1540uF i would use 6 or 7 chargers running on 4 D batteries at 3V.

JamesRPatrick says: Jan 28, 2010. 6:40 PM REPI'm considering turning a barrel out of aluminum with a spool for the coil built in. would this create any problems with conductivity? The barrel wall would bearound 1/16" thick.

eggman says: Jan 29, 2010. 7:19 PM REPthis would cause large problems with eddy currents inhibiting the force of the field getting to your projectile. you can inhibit these currents by cuttingslots lengthwise in the barrel to eliminate continuity along thecircumference, but it is best to use a plastic barrel. i like the idea of milling the spool right

onto the barrel, maybe you could use a block of teflon or something of the like.

JamesRPatrick says: Jan 29, 2010. 8:11 PM REPThanks. I feel so stupid not thinking of that...

hunter566 says: Jan 28, 2010. 3:57 PM REPI cant fine any disposible cameras around where i live is there a web site or somewhere else i can get them

kerneykid1 says: Jan 24, 2010. 6:53 PM REPthis is pretty amazing man

hunter566 says: Jan 21, 2010. 11:37 AM REPCan you use a heavy duty toggle switch instead of the heavy duty rocker switch

riku1 says: Jan 21, 2010. 6:54 PM REPyes you can but if u get 1 with an led it wont light up and dont try to super glue it in place because it will ruin the switch it really po'd me when thathappened to mei had to learn the hard way.and use one with any volt that is rated 12v or higher and it will work and ithas to be at least 30amps.i didnt want to use a relay either.but mine worked well witha toggle switch.and if anyone knows the location and price of hobby composite that is usedto make ice rinks ic christmas villages i would apreciate it if u could tellme(using that to fix my bb gun im puting my coilgun in)reply A.S.A.P. plzO_o

Gladiater says: Jan 13, 2010. 9:37 AM REPis it bad if i use chargers from different kind of circuit boards? cause i've got alot of disposable camera's, but they're from like 5-7 different brands ofcamera's.Oh, and another question i've got quite some capacitors but the microfarads or voltage are not imprinted, how can i f ind out? if you need, i can supply sompictures if necesarry.

rooftoptile says: Jan 19, 2010. 3:41 PM REPyou need to get a multimeter. theyre like ten bucks at radioshack

eggman says: Jan 19, 2010. 6:04 PM REPmost multimeters won't measure capacitance. we generally disregard unmarked capacitors.

Gladiater says: Jan 20, 2010. 6:19 AM REPSo you're basically saying i should throw away the capacitors? that would be a problem cause i dont have any others. no other solution?

eggman says: Jan 20, 2010. 1:26 PM REPas a last ditch effort you could just assume they're ~300V and ~80uF. there are big problems with this though, as they could easily overvoland explode gloriously. if you realll lly needed to use these, you could go out and get a capacitance meter and then find the rated voltage.
http://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/rooftoptile/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/rooftoptile/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/hunter566/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/hunter566/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/kerneykid1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/kerneykid1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/hunter566/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/hunter566/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/JamesRPatrick/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/JamesRPatrick/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/JamesRPatrick/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/JamesRPatrick/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=comments


19/21


eggman says: Jan 19, 2010. 2:38 PM REPdo you know how much current a bank of 5 chargers would pull? i tried powering them with an lm317 at 2.5V and it only charged to 48V before itoverheated and shut off. this vreg was rated to 1.5A

rwilsford07 says: Jan 19, 2010. 5:30 PM REPIn my experience the camera circuits will pull as much as they can, which is why your power source, i.e. how many batteries at 3V you have in parallel,determines the output power and the camera circuits will break themselves before limiting the input current.

For my PAR-1 the output power of the 6 chargers was about 50W with 8C batteries at 3V. That means that that charger bank pulled 16.7A from thebattery bank, so quite a bit more than 1.5A, although the LM317 probably limited this to less than that.

If you can't use 3V worth of alkaline I really recommend a Buck converter to lower the voltage instead of a linear one, as the linear converter will

decrease the voltage conversion efficiency by much more than half (For example if you plan on pulling 3V at 1.5A from an 18V source the linear regulawill have to dissipate the dif ference in voltage times the output current (18V-3V)*1.5A = 22.5W, that's a 16% conversion efficiency. One the other hand buck converter will only take a l ittle over the required power and operate usually around 90%. Keep in mind the charger circuits operate around 16%efficiency. Of course in the end a boost converter will win out on both size, power, and total efficiency (usually about 70%).

moshee says: Jan 19, 2010. 3:32 PM REPWhy would you use a voltage regulator for camera circuits?

eggman says: Jan 19, 2010. 6:09 PM REPi need to bring 18V down to 3V to power the chargers.

Barrettkg says: Jan 15, 2010. 8:18 PM REPOk, I'm having a BIGproblem trying to figure out the size of the coild from the 'ibleusing 22 gauge wire, how long should I make the coil and around what size bolt should i wrap it around?

tim.vrakas says: Jan 15, 2010. 3:26 PM REPI have some old NP1 12v batterys how do i make them work

tim.vrakas says: Jan 14, 2010. 1:13 PM REPcould someone tell me where to get camareas

max0506 says: Jan 13, 2010. 10:22 AM REPHello guysI am making a coilgun made of a disposable camera and some capacitors.I have made a drawing with google sketch-up. Could you please check if I have made all the connections right? ( I am not an expert yet)

www.elektronica_stuff.webklik.nl/page/voorpaginaplease reply

Gladiater says: Jan 13, 2010. 9:48 AM REPoh and one more thing: you say i ts safe to put 3v on the chargers, but they normally work with 1.5v, so what's up with that?

riku1 says: Jan 12, 2010. 4:45 PM REPhow well would a 15-25 layer coil work ifit was about 2-3 cm long on a straw and was out of 20 gage wire that is in most down step t ransformers and howmany micro-ferads at 330v would it take to launch the round at least 20yds as a single-stage coilgun?

riku1 says: Jan 8, 2010. 1:23 PM REPso even if i dont mod the circut and just put it in the coilgun how it is when u take it apart i would need another relay?

JamesRPatrick says: Jan 11, 2010. 1:46 PM REPAre you even reading these responses?

riku1 says: Jan 11, 2010. 4:49 PM REPyes i amand there are 2 types of relays one uses an electro magnetic switch and keeps it turned on when pored is appliedand the other converts dc curreninto ac currenti took two relays that were different off of a circut board and checked their serial#s and then took em apart and one stayed there and the othermoved back and forth really fast
http://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/JamesRPatrick/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/JamesRPatrick/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/Gladiater/?utm_source=pdf&utm_campaign=commentshttp://www.elektronica_stuff.webklik.nl/page/voorpaginahttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/max0506/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/max0506/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/tim.vrakas/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/tim.vrakas/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/tim.vrakas/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/tim.vrakas/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/Barrettkg/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/Barrettkg/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/moshee/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/moshee/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/rwilsford07/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/rwilsford07/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=comments


20/21


that is how i know this and on top of that u only NEEN a relay if u mod the camera circut because they already have one in them and u can yust usan on off toggle switch to fire though it can shock u if not hooked up correctly

eggman says: Jan 11, 2010. 7:05 PM REP"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."

also, i don'y know why you're so convinced that there is a relay in the circuit already. there is not. all there is on the camera boards is the largecapacitor, two transformers, and somemiscellaneous smd resistors, capacitors and diodes.

riku1 says: Jan 11, 2010. 8:45 PM REPu know the small transformer thing that usually has yellow tape and a green wire coming out of it?

that is a very small relay that turns the light on when it is done charging the capacitorsand u definately dont liuve in alaska because a toggle switch is cheaper up here

rwilsford07 says: Jan 12, 2010. 12:57 AM REPriku1, the small transformer is just a transformer, the transformer together with the additional transistor and resistors turns the 3V DC inthigh voltage AC and the output diode rectifies it into DC which charges the capacitor.

A relay is an electromechanical switch, I recommend goggle. In most cases a 30A toggle switch wi ll be more expensive and larger than 30A relay. It is not used in the charging circuitry, it is used to switch current from the charged capacitor bank and through the firing coil.

Eggman knows what he is talking about

riku1 says: Jan 12, 2010. 12:22 PM REPi know how the circut it works and the camera circuth i am using are different then the ones you are using that is why i am saying thiim not tryin to be an ahole about it but the ones i am using have a relay 2 or 3 diodes 1 led and 1 transformer they are set up the sa

way the camera circuts u used but are built differentlyand this orignally started out as askin i f the relay is used in the moded circur because if it was i didnt need to buy one because theones im using already have one in them and im not moding the circuts because the ones i have are totaly diferent than the ones youusedand if i made anyone mad i am scinceerly sorrybut i thought i mentioned that the circuts are different and had i mentioned that we would have avoided thisonce again i am sorry

eggman says: Jan 12, 2010. 1:09 PM REPpost a picture of the circuits you are using. chances are you will need a relay because the one that may possibly be on yourboard isdefinitelynot rated to switch 30A

riku1 says: Jan 12, 2010. 2:26 PM REPi decided to not use a relay and to use a toggle switch instead because ifound 2 30 amp toggle switches in my room not in uand that are rather smallbut i do appreciate your help and it willprove useful in the future&unless my mom decides to be nice i dont have a camera to take pics with

riku1 says: Jan 12, 2010. 12:29 PM REPand the reason i thought it was used in the charging circut that u used was because of the way the yellow wires conect toh the cbank and the charging circut in pic#2 on step 4srry for the frustration and confusion

riku1 says: Jan 12, 2010. 4:46 PM REPhow well would a 15-25 layer coil work ifit was about 2-3 cm long on a straw and was out of 20 gage wire that is in most dowstep transformers and how many micro-ferads at 330v would it take to launch the round at least 20yds as a single-stagecoilgun?

eggman says: Jan 11, 2010. 2:08 PM REPi really don't think he is. the relay is a SWITCH. it has nothing whatsoever to do with converting ac to dc, or transformers, or anything. all it is is ahigh rated switch.

eggman says: Jan 9, 2010. 10:49 AM REPare you sure you're clear on what a relay is and what it does?
http://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/rwilsford07/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/rwilsford07/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/eggman/?utm_source=pdf&utm_campaign=comments


21/21

riku1 says: Jan 9, 2010. 5:55 PM REPiv done that it didnt helpand i asked my uncle who works with electronics every day what a relay dose and he said that it converts ac current into dc current and he knows that kindof stuff

view all 2511 comments
http://id/Coilgun-Handgun/?comments=all&sort=OLDEST#commentshttp://id/Coilgun-Handgun/?comments=all&sort=OLDEST#commentshttp://id/Coilgun-Handgun/?comments=all&sort=OLDEST#commentshttp://www.instructables.com/id/Coilgun-Handgun/?utm_source=pdf&utm_campaign=comments#DISCUSShttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=commentshttp://www.instructables.com/member/riku1/?utm_source=pdf&utm_campaign=comments

coilgun handgun

Documents