Three Stage Optically Triggered Coilgun
Principles of Engineering Spring 2010
Designed and built a three stage optically triggered 2-axis coil-gun with a group of fellow students. My primary role here was in the electro-magnetics of the system, designing the coils and capacitor banks required, and fabricating the barrel and coils.
A coilgun is made by wrapping thick magnet wire around the barrel of a gun. When a burst of current is sent through the wire, a magnetic field is generated that pulls all ferrous materials towards the center of the coil. This is what we planned to do, with one major change: we attached three coils to the barrel.
This greatly increases the amount of energy involved but it raises a few complications. The coil continues to pull the projectile back into its center as it passes into the next coil, which means that we need a way to turn off the previous coil just as the projectile passes into the center of it. In order to do this, we placed a photodiode under the coil which will trigger a current gate when the projectle passes over it (cutting off the light) which turns on the current to the next coil. In this way, we produced a much more powerful coilgun than a single coil set up.
We decided to place the gun on top of a mount, making it a multi-stage coilgun turret. The mount uses a servo and a stepper motor attached to a turn table to rotate the gun and tilt it up and down.