are projectile accelerators that use electromagnets to pull and then push a magnetic projectile, accelerating it to high velocities. Coilguns are either single-stage or multi-stage; a single-stage coilgun uses one electromagnet to propel the projectile, where a multistage uses two or more electromagnets in succession, each increasing the velocity of the projectile rapidly. In this case, the students built a four-stage coilgun.

The overall concept of their gun is simple enough. It's controlled using an Apple iDevice--an iPhone, iPad, or iPod Touch. The iDevice connects to the coilgun using Wi-Fi and a Wi-Fi hub. The coilgun can turn or move up and down on a turret and fires using the iDevice interface. It also has a camera on the end so that you can see where it's pointing on a laptop. I don't know about you, but I see these students working for the some day.

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