Barry's Coilguns

Barry's Coilgun Mark I

What if I made a multi-stage coilgun, with digital timing to control the firing sequence? How well can it work?


My first model, the Mark I, will launch small projectiles at a modest speed. In this (my first coilgun) there's a few things I want to accomplish:

  • Build a coil gun with predictable and controllable characteristics.
  • Identify the main elements of design. That is, what variables affect performance, and how?
  • Close up picture of drywall screwLaunch small (< 1oz.) projectiles at moderate speed. They should go fast enough to be fun, but not so fast as to cause permanent damage to body parts.
  • Use inexpensive and common components.
  • Simple mechanical assembly with a minimum of mechanical adjustments.

To be precise: My goal is tolaunch a 1-inch screw or nail 16 feet straight up . (That's the height of our living room ceiling, or about 5 meters. I hope it doesn't stick there!)

Design of the Mark I

I just hate to mess around with fiddly little mechanical adjustments, so my main goal is the "simple mechanical" part. I want to eliminate adjustments as much as possible. Therefore, the Mark I will have a few coils controlled entirely by digital electronics. (I am much better at electronic assembly than working with tools!)

I choose to run my coils in a pre-determined timing pattern. I know the performance would be better if there were a detector to fire coils according to position, but that would mean fiddling with the detector's position and the length of the projectile. So I won't use detectors.


Building the electronics for a coil gun involves several components. Fortunately, today's electronics offer a rich variety of possible timing and power control devices. Here's what I chose for the Mark I:


Building the mechanical parts of this coil gun involves several components.


Because this coilgun is running open-loop, we need to calculate when to turn on/off each coil. Here's how:


As of 20 Feb 1999, this coilgun has achieved 1.7 m/s with one coil:

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