MoMed: An Affordable Mechanical Ventilator

Development of a working prototype of an affordable mechanical ventilator is discussed in this paper. The device uses a bag valve mask and two pushing handles to compress it and force-feed the air into the patient’s lungs. A stepper motor along with a reduction mechanism made up of belt drives and spur gears are used to drive the pushing handles. A flow sensor is used to measure the airflow enabling closed-loop control of the air volume supplied to patients based on their lung parameters, i.e., compliance, resistance. Two absolute barometric pressure sensors are used to measure and report the gauge pressure and trigger the alarm buzzer in the case of high respiratory pressures. The prototype is tested using a test lung and the test lung’s parameters are estimated using the flow and pressure data logged by the onboard microcontroller. Estimated compliance is very close to the test lung’s reported compliance but the resistance is higher and the reason seemed to be the tube used to connect the prototype to the test lung.