Added an idea for an "African Solution"

African_Solution.txt

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+Here is an "African Solution"
+
+Do a more universal construction!
+Use car parts like:
+-Wiper motor of VW/Skoda/Audi MQB model series "golf class".
+Get Parts at your local car dealer with oem part numbers.
+Advantage: Car manufacturer must provide logistics 15 years after end of production of his car series.
+Also there are a lot of after market parts.
+So look for matching car parts.
+Also add functional safety:
+-have alternative way if processor fails.
+-have two processors and do lockstep, or have a minimum PWM-speed generated by hardware (e.g. NE555 and MOS-FET)
+Plus 12V ---- MOTOR --- NFET1 (controlled by cpu) --- GND
+                                     + NFET2 (controlled by NE555-PWM) ---- GND
+
+I like your approach and I also have 2 ambu bags for my family and I also build myself an electrolysis device from sewage pipes to produce oxygen. But I did not invest too much time into the thing.
+Better Ambu bags have a 40mm water blow off valve, 
+so I can just take a of the shelf electronics lab supply, add the wiper assembly of a car and run the motor at the desired speed. (Voltage controls speed, current limit controls maximum torque of a dc motor).
+Also one can use a switch mode power supply to generate the motor supply voltage and control the voltage at the error amp to give the desired speed.
+Here one can also use the pressure sensor to generate a set point for the error amp.
+this can be done using analog electronics which are more reliable as an op-amp does not hang or needs to be programmed.
+
+
+
+Mechanics:
+Use a windshild wiper.
+https://youtu.be/1tl2AZ2k7WQ?t=291
+Look at the two arms that move the shafts of the wipers. Add some pads like wooden pieces with screwed on (mind the size of screws not to puncture the AMBU!!) pipe holders, that connect the wooden pieces (plates of 15cm x 6cm) to the small arms of the mechanism which forms a parallelogram. So you have 2 small plates pushing 2 AMBU-BAGS that sit in a wooden wine box.
+So you can put it alltogether into a wooden (wine) box and you can squeeze 2 AMBU bags at the same speed and density. Not perfect but scales better.
+This is far more quicker, as you can go to a scrap yard or a car parts shop and get a matching wiper mechanism of any car which has a similar mechanism. 
+Also wood work is quick and easy compared to cnc metal work.
+Just screw or nail the wiper mechanism into the wooden box. Sand the surfaces so they dont hurt the ambu and clad it with some cloth if you want to further protect the AMBU from friction and wear.
+No CAD drawings needed, just use wood tools and build the wiper assembly into a wooden box, use your intuition to make it fit.
+Looks like an "African solution" but it scales far better.
+
+B                        Wiper Mechanics                          B
+O                   +---------------------------+               W O
+X  ( ======= )    W/ L                         /W (=========)   O X
+W  (AMBU-BAG  )  O/    I NK                   /O (AMBU-BAG2)    O W
+A  (  1    )    O/       Wiper-Motor         /O  (        )     D A
+L   =======    D/                           /D  (=========)     E L
+L              +---------------------------+                    N L
+
+///
+Update:
+Looking at the code of the original, I see that the motor just pushes to a certain ammount and then retracts to have a certain pressure and to hold it.
+
+So using this approach only one AMBU can be used.
+
+//
+Doing it more "African"
+One uses two AMBU BAGS, rotates the motor through and just controls the 
+speed of the motor, so the motor always gives full strokes to the AMBU BAGS.
+In order to "control" the Pressure one uses the blow off valves in the AMBU 
+BAGS that have an override setting but here must be set to e.g. 40mm water
+to protect the lungs from overload.
+
+AMBU bags are made to be squeezed by humans without special controllers 
+so it is sufficient to have a motor of variable speed squeezing the AMBU bags.
+
+If one makes the box a bit to big one can add some moveable wooden parts to 
+control the ammount of compression the bag experiences from the motor,
+so the bag can be pushed more against the oscillating wood board or retracted
+a bit in order to control the volume to be send to the lungs with each cycle.
+
+So one can just use a "speed controller" which is a variable power supply 
+or a PWM speed controller of a model car to feed the wiper motor.
+It is important to have alternative ways and to connect a pulse oxymeter
+to the patient to be quickly alarmed if the machine fails and the oxygen in the blood declines.
+By all means have the box open, so a person can grab the AMBU bag and continue to operate it by hand as intended by the vendor of the AMBU!
+
+