In April 2020 I contributed to efforts to rapidly scale ventilator manufacturing by making a fully machinable ventilator based on the Go2Vent. Fortunately, these were never needed, but I got the chance to design a neat manometer that is easily fabricated with manual machining and does not require calibration.
The device measures lung pressure by using a main air intake channel to pressurize an array of vertical channels, each of which has one to five steel dowel pins. The channels are open at the top so that air pressure from below can raise each stack of pins until they contact the top, sealing off airflow in that column. The manometer is read by viewing which pins are at the top, with each channel representing an increment in pressure.
Catherine Pavlov 