At this point I can't remember if my intent was to actually build a ventilator, although at the time I seem to remember a relative lack of posts on StackExchange pertaining to ventilator design, despite it being all over the news.
I think my goal with this post was in some way to contribute to open-sourcing ventilators. It turns out I did not know how complex a ventilator was, and as a result I discovered my basic design was missing a few parts although the basic functioning of it could potentially conform to the guidelines for pressure controlled ventilation (PCV) however missing a few parts thus making it most accurately a BiPAP machine. At this point the details aren't really all that important (and they are all in the guidelines), since I don't think I will ever build this thing. So anyway, my idea; here are some doodles I hope they are self explanatory:
ascii art schematic of the Party-Balloon BiPAP:
(close-circuit when balloon is full) ....switch.................. . __\__ . . / \ ____._____ . / party \ |Controller| . |balloon| ----.----- . \ / . . \ / . . \_ _/ . . /_\ ............ . || . .exhaust regulator=T=====++=======++=====T==========/switch _I_ solenoid || solenoid (open-circuit when exhaust flows) / \ valve || valve | | (inhale) || (exhale) | | (oo) | air | \?/ | | T patient |_____| /\
controller logic table:
switch switch inhale exhale party exhaust solenoid solenoid 0 1 1 open 0 closed done exhale: begin inhale 1 1 1 open 1 open balloon full: begin exhale 1 0 0 closed 1 open exhaling: stop air intake 0 0 0 closed 1 open continue exhaling: air flowing
here's my new improved truth table:
----controls---- State e b next exhaust_s intake_s 0 0 0 1 open closed 0 0 1 1 open closed 0 1 0 0 closed open stay inhale phase 0 1 1 1 open closed begin exhale phase 1 0 0 1 open closed stay exhale phase 1 0 1 1 open closed 1 1 0 0 closed open begin inhale phase 1 1 1 1 open closed State = 0 = inhale-phase, State = 1 = exhale-phase exhaust flap: e = 1 = closed-flap, e = 0 = flowing-exhaust balloon switch: b = 1 = balloon-full, b = 0 = not-full
...and associated logic diagram & karnaugh map (done in GIMP):
...and my resulting digital logic / logic-gate circuit (Logisim):
So there, I came up with a very basic logic diagram. I'm not sure the rest of the idea is sound though; I took a lot of inspiration from Macgyver.