So here are the parts that I will be using to create a "breathing hill". The first solenoid let's air in, the second let's it out. The piece of aluminum will be faced by a milling machine, then drilled and tapped to allow for some attachments to be screwed into it. I think I will be getting a larger inner tube, but for now, this is good enough for the purposes of creating a model. There are many more details that need to be worked out, but this is the basic bone structure.
