See video at https://youtu.be/jtI85dCgnkM .
Also click on picture files below.
(mod edits)
the video is made 'private'
edited: made public now
This is a great project.
A suggestion for next step: While a ventilator is used in an environment where the patient has one on one human care 24x7 it would be great to have a second processor that monitors all the functions and alarms if it senses anything not right.
Another part is making it portable so it can be used in an ambulance or while transporting the patient even within the hospital.
Keep going - your onto something 
Great project GL wit that!
Awesome project, really liked it. Although, I have a friendly suggestion, you should use TFT LCD instead of 20x4 LCD as that one looks professional. 20x4 LCD gives it a student project look.
Thanks for the encouragement fellows! I deeply appreciate any and all advice, questions, comments etc.
jackthomson42, those 20x4 LCDs were what I had sitting around (true for the model boat servos, wood, and Arduino MEGAs too). I've been thinking about a backlit TFT LCD too. Which one(s) would you recommend? And, can they be programmed by an Arduino?
smitthhyy, about all it "senses" now, is air pressure inside the mask. Useful for letting it (optionally) delay for a few seconds in hopes the patient starts breathing on his own, if he doesn't start breathing within X seconds, the machine starts up and helps with one breath for him. Wash rinse repeat. Several doctors have pointed out that there is always a danger of overpressuring a patient's lungs, which can cause significant injury. Next model will have another knob where the doctor can set the maximum allowed lung pressure, if it reaches or exceeds that, the machine backs off on that breath and sounds an alarm. Might soon have an air-velocity sensor too.
Another projected change coming: The BVM is designed to let the patient inhale through the bag (with a squeeze from the doctor or machine if needed), and exhale through a sideways valve so he doesn't inhale the air he just finished exhaling. But if I put a hose between the bag outlet and the mask, then the patient WILL inhale part of his own exhalation (the part that's in the hose between his mouth and the BVM unit), which is unsatisfactory.
I haven't been able to take apart the BVM unit, and don't really want to. I want the doctor or helper to be able to whip a fresh BVM out of its factory bag, pop it into the machine, and go, without having to take it apart or otherwise fiddle with it.
So on the next model, the bag-squeezer mechanism will be attached to the powersupply/controlpanel/Arduino console by a long cable, 3 feet or more. The mask will be attached directly to the bag/mask unit (as it was originally designed), so the patient's exhalation goes one way while the inhalation comes in another (through the bag), as the BVM was originally designed to function.
The bag-squeezer will be two lightweight levers hinged together at one end, with the servomotor and drawstring at the other. It will sit on the patient's bed near the patient's head or chest where it can squeeze the bag, while the bag rests next to his nose and mouth, as it must when the bag is attached directly to the mask. The present arrangement is unsatisfactory. I should have thought of this earlier.
Thanx all, please keep the comments coming!