It’s true that a lot of the projects we feature here (and build ourselves) are created to accomplish some sort of goal. But, many times the project itself is the goal. That’s the case with [Proto_G’s] self-oscillating pneumatic machine, which he built with no particular use in mind.
[Proto_G] started this project simply as an engineering exercise; he just wanted to see if he could make it work. That’s the kind of spirit we find very admirable — not every project needs to be the culmination of your life’s work. Sometimes, just doing the thing is motivation enough.
Like any good engineer, [Proto_G] thinks mechanisms and linkages are neat. And, even Hollywood agrees that an oscillating mechanism is not a trivial design. Adding pneumatics to the mix just adds to the interest. The basic idea is to switch opposing valves on and off when the carriage reaches each side, which is accomplished with pneumatic actuators which trigger air pressure in a “magnetically coupled rodless cylinder.”
The magnetically coupled rodless cylinder is a pretty interesting component, which utilizes a magnetic piston within the cylinder to move the magnetically coupled carriage on the outside of the cylinder. This lets the piston work with pressure in both directions, as both sides are sealed. Could this have been accomplished in other ways? Sure, it could. But, this way is pretty darn cool, and is something you can add to your list of mechanisms that you might use in future projects.