On Fri, 27 Mar 2020 18:19:45 -0400, "Mr. Luddite"
wrote:



Apparently, after promising to
tool up to produce ventilators, GM started
demanding excessive up front money, jacking
the price per ventilator up and
producing less than was
originally promised.

Trump just punched back, invoking the
Defense Production Act to require General Motors
to produce the ventilators, like it or not.


That's it.

I am trading my GM Canyon in on a Ford.

There was a guy from a ventilator company on NBC tonight saying they
have a deal with GM so let's see how that goes. These things still
take time. It took almost a year before the Guide Lamp division could
tool up to make M3 submachine guns in WWII but once they did, they
were rolling out the door by the thousands. I just wonder what we are
going to do with a half million ventilators when this is all over.

I am still fascinated with the bare bones designs after looking at the
MIT thing. I see a few things they could improve right away. It is
clear these boys were working with what they had in the robotics lab
and the actuator is far too complicated, perhaps too fragile too for
something that has to go three quarters of a million cycles or more a
month. I think some kind of industrial bellows, a gear rack and a
stepper motor might be more appropriate and cheaper. I doubt you even
need a PIC. Maybe something as simple as a dual 556 timer, a D
flipflop to make pretty square waves and a stepper motor driver chip.
Timer one is the stepper motor drive and timer two sets up the timing
and length of the stroke, in conjunction with the motor speed. A
couple of opto sensors to tell you where the rack is and a pressure
regulator. The brain could be a couple of garden variety CMOS gates
just determine which way to go based on where the opto sensors says it
is. I doubt I am much over $20 in parts plus the price of the can, a
filter and the mask hose assembly.
The reality is once someone designs the can and the mounting points
for the hardware in a pattern that any metal fab shop can bang out,
this is easily that $100 ventilator and it could be built in a light
industrial bay anywhere.
That is just me thinking out loud. I have every confidence American
ingenuity will solve these problems pretty fast.
BTW, no gloves, use a dog poop bag if you are just handling random
objects that might be contaminated.
(an idea from the military Facebook group)