OP-Vent
OP-Vent, a project initiated by Stanford University is developing a simple ventilator can be built with just two off-the-shelf components: a proportional solenoid valve and a microcontroller (and a pressure relief valve for safety). The microcontroller modulates the valve to control the flow to the patient. In this simplest configuration the ventilator operates “open-loop”. With a calibrated sensor and either regulated input pressure or input pressure monitored with a sensor, flow rates accurate to +/- 20% can be achieved open loop.