Yes, it has been done before, but the point with Ben's project was to create a cheap and easy version. If you were to build one with pneumatic systems it would cost way too much. AND the crusher in the video needed a custom-built frame to withstand the force from pneumatic systems.
I liked the build they were attempting to do, and i think it could have been done with a linear solenoid like they were trying to build, but it could have been just as compact if they had used a purchased instead of self wound solenoid. The biggest problem they didn't look at before building was how much pressure it actually takes to crush a can, then you could find a properly rated solenoid, and if you pop a microntroller or some other small circuitty it could be made to run on a push button or cycle with a toggle switch. But again i do like that they were trying to show that you can make your own lenear solenoid which could be a project in and of itself.
