Truly automatic? Surely you mean truly "semi-automatic."
I understand what you're trying to do. I look forward to seeing it completed.
You might find the "bike pump" extending when the pressure chamber is filled - you would need a valve somewhere on the tubing to prevent that, or you might not, depending on the pump.
That's definitely what I meant, I just forgot to put "semi-" there. Thanks for pointing that out; I fixed the error.
Tanks for the tip about the bike pump, as well as your support. I look forward to seeing it completed, too.