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Future Weapons Systems Technology Project

The EM-15 coil gun is a handheld, battery powered (12 VDC) rifle that is capable of launching a .30 caliber metallic projectile at adjustable velocities. The electronic circuit consists of a voltage step-up transformer converter, a Cockcroft-Walton voltage multiplier cascade, a capacitor energy storage bank, a voltage comparator to set the charge voltage on the capacitor bank, an SCR switching section and a single accelerator coil. Other components of the gun are the barrel, breech loading mechanism, battery supply, capacitor bank, control panel, display, projectile, pistol grip with trigger assembly and an aluminum stock that contains all of the components.

Watch the movie to see the possible future of military rifle technology. Email me if you'd like the link to the orginal movie file (my download quota has been getting exceeded every month)

Plans Available Soon
The full detail plans explain the design and construction of every part needed to build this exciting technology - right down to winding the transformer needed for the high voltage converter circuit.

EM-15 Main Circuit Board
The circuit board contains the step-up transformer converter, a cockcroft-walton voltage multiplier cascade, a voltage comparator to set the charge voltage on the capacitor bank, an SCR switching section, control panel and connectors for the 12V battery pack, capacitor bank, accelerator coil and the fire switch.

Transformer Construction
The plans include the detailed instructions to wind the step-up transformer from parts that can be obtained at any hardware store. Once you know the lost art of transformer building you will be able to use this knowledge for many other exciting high voltage projects.
Energy Storage Capacitor Bank
The Capacitor bank is comprised of ten 200 VDC @ 1500 uf capacitors wired into a configuration of 1000 VDC @ 600 uf. The charge time between shots is approximately 16 seconds.

Fire Switch And Pistol Grip
The pistol grip is mounted to the bottom of the guns aluminum frame and holds the trigger - a standard microswitch.

Capacitor Bank And Side Panels
This picture shows the capacitor bank and aluminum side panels mounted to the bottom of the frame and the pistol grip with trigger.

Barrel, Accelerator Coil And Breech Loader
The barrel is nylon painted flat black, smooth bore, 14-inches long with a 3/8-inch diameter. The projectile is loaded from the top and seated into the proper position in the coil with the bolt. The bolt contains a small magnet that holds the projectile in place until the gun is fired.

Front, Side Panels, And Top Covers
The covers and side panels are constructed of aluminum, primed and painted flat black.

12 Volt DC Battery Pack
8 x 1.5 volt AA

Fire Switch

Side View Of Control Panel And Circuit Board
The gun is 19.5 inches in length and 3 inches wide.

Breech and Coil
The initial position of the projectile seated in the coil is important to achieve maximum velocities at different voltage levels. The adjustable breech accommodates experimentation with different types and positions of projectiles.

A 1/2-inch projectile was cut from a piece of .30 diameter cold rolled steel and then filed on one end for a more aerodynamic shape. Iron crossbow tips that can be purchased at WalMart make ideal projectiles for this type of coilgun.



Nuts And Volts Magazine Article

The EM-15 was featured as a DIY article in the March 2008 issue of Nuts and Volts magazine.

Capacitors C3 and C4

Note that there was a typo for the values of capacitors C3 and C4. The correct values for C3 and C4 are .01uf at 1.5KV DC or higher, ceramic disc.


There have been a few questions about the reset switch SW2. If SW2 is pushed the charging section of the circuit will stop oscillating - this was used when designing and experimenting and can be left out if you want.

D9 is used to protect the capacitor bank from reverse bias due to back EMF from the accelerator coil..