The Bobbinator

Linear actuators are motors that work in a straight line. They’re very useful for controlling valves and levers, building robots, and retrofitting old mechanisms for digital control. The simplest form of linear actuator has only 2 positions, while more complicated actuators can be positioned just like stepper motors and servos.... Read more »

Better Nerf Gun

Like most geek-filled offices, at my workplace we have several Nerf guns and similar toy weapons floating about. Not impressed with the performance of my colleague Lester’s Nerf Maverick, a mainstay of Nerf’s suction-cup-dart-firing “N-Strike” series, I decided to build a better Nerf gun myself. Here’s the result: a simple... Read more »

Build a Lawnbot 400

I have always hated mowing the lawn. I was the guy who only mowed when the grass got to be 6″ taller than the neighbors’ lawns — not because I don’t like my neighbors, but because mowing was such a pain. After being hit by one too many rocks, I... Read more »

The Fire Piston

Carl von Linde was dead tired. The eminent engineer, considered the father of the modern refrigerator, had just returned to his home in Germany from a lecture tour that took him to, among other places, Malaysia. This being the late 19th century, the voyage had taken months. Von Linde had... Read more »

Electromagnetic Aluminum Levitator

About 13 years ago I learned of some military research into a satellite- and missile-defense device that would propel projectiles using Lenz’s law, which governs the direction of electrical current induced by a changing magnetic field. I decided to make a little gadget based on the same principle for my... Read more »