That's an awesome neat idea, thanks for sharing.
I was going to build one, an purchased ez vacuum instead, when I learned I need the vacuum switch.
I don't think I can get that kind of "quick switch" here, now I am thinking using a switch to activate a relay
Any idea of sealing the DIY vacuum tube sealing ? Right now I just pucture a hole, insert the tube and give some aquarium silicone glue, which gives me trouble after a few jobs.
My only Idea is to ask a friend to lathe a nozzle with a base that I can insert between the plastic tarp.