First of all, what is a coilgun? A “coilgun” or “Gauss gun” is a form of gun that uses a high powered electromagnet to shoot a projectile instead of using gunpowder and a firing mechanism. The gun works by inducing a magnetic field in a coil of wire around the barrel using an extremely short, but high energy burst of electricity. This is usually accomplished by using capacitors and a high voltage charging circuit. When fired, the electromagnet that is created pulls on the ferromagnetic projectile (able to be magnetized) with great force, causing it to quickly accelerate towards the center of the coil. In the fraction of a second it takes for the projectile to reach the center of the coil all of the power supplied to it has been exhausted and the magnetic field has dissipated. This allows the projectile to continue out of the barrel with its own momentum. Coilguns can vary in complexity from the most complicated, multi stage, computer controlled designs, to the simplest single coil, untimed models. Below is an example of a single stage coilgun and the illustrated step by step process of firing a projectile.

1.) The projectile is loaded into the barrel and the capacitors charge.

2.) The capacitors are discharged into the coil, thus inducing a magnetic field that pulls the projectile towards the center of the coil.

3.) Before the projectile reaches the center of the coil the power from the capacitors is exhausted and the magnetic field dissipates.

4.) The projectile continues out of the barrel with it’s own momentum.

Now for a little chitchat about my coilgun. I built this coilgun last year when I stumbled apon a link to the CoilOsapien (a coilgun mounted on a robosapien!) on Hack a Day . That project inspired me to go about building my own modified version. I baciaclly took the same circuit, beefed it up with some more flash capacitors, put it in a nice enclosure and hooked up some sweet old school charging/firing controls. Oh, I also made a modular barrel/coil connection so I could experiment with different coil and barrel combinations. If you want to see how to build your own coil gun, check out the Coil Gun v2.0 page. It has step by step instructions with pictures and videos.