@Mackrock I've got an idea for you. Obvious the oscillating device would have to apply pressure to powders, right? Since solids do not move. So if you were to use a wall in which you can enclose a liquid, like water, and put pump on the bottom (for electric control.) The water would move up and down(with the pump), perhaps pushing a gas?
Oscillating device: a "switch" (not the element) opening and closing at regular interval (every n frames). I could produce pseudo AC current... In fact, rather square waves.