TD (@enginetankard) will concur--- I wouldn't shut up about it when he was here.
Chinese laser cutters often come with a little air pump; it's used to blow smoke away from the optics while cutting. You're supposed to set it up somewhere near the machine, and run an air tube in. It's a simple little AC coil/solenoid attached to a piston. It also vibrates enough that it will walk across a workbench under its own power unless you bolt it to something. I want my air pump internal to the cutter, and I want it automatically controlled to only be on when cutting. Vibration would be a major problem mounting it inside the case, so I took two of the little ones, machined a custom output valve housing/gasket and connected them in opposing orientation. Viola! No vibration.