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The Bobbinator

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. I needed 32 linear actuators […]

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Better Nerf Gun

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 weapon, single shot only, but […]

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Build a Lawnbot 400

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 decided I no longer wanted […]

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The Fire Piston

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 seen and learned much during […]

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Electromagnetic Aluminum Levitator

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 kids, to get them interested […]

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Clean Metal: Remove Oxidation or Paint From Metal at Home

Clean Metal: Remove Oxidation or Paint From Metal at Home

I love using old machine parts for my projects; often their workmanship surpasses that of anything new, and you can get them cheap or even free. Find a junkyard full of ancient, rusty industrial equipment, and you can build almost anything — or at least be inspired to, which is half the battle! But many […]

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