Dr. Khalid Mehmood Ul Hasan

In Pakistan, hundreds and thousands of people die every year in search of medical facilities especially breathing equipment. Our project focuses on the development of a fully functional and low-cost ventilator with a wide range of user friendly controls. It involves the design and making of a prototype that will provide oxygen-regulated, volume and pressure-controlled air for mechanical ventilation. Precisely calibrated sensors will provide feedback signals for a closed loop system. A DC air pump controlled by a modified buck converter pumps air into the lungs via a mouth piece. Gating signals to the converter are generated in response to real time values of precisely calibrated pressure and flow-rate sensors for their respective cycles. The flow rate sensor, AWM720P1, has been calibrated using a curve fitting tool in MATLAB. This results in the development of an equation that allows mapping of an entire range of permissible voltages to discrete flowrates. Pressure measurements are made differentially using sensors BMP180. Raw output voltage levels from the sensing units are converted to variable-duty PWM signals and then fed to the microcontroller for feedback. This additional measure is for circuit isolation. Additional features include oximetry to detect oxygen levels in medical air, a GUI developed in Raspbian environment for easy access to system settings and the option to connect the ventilator to a LAN. The ventilator will both be directly powered and battery operate-able for flexible use. Our prototype is being built to support a wide range of controls so that it is adaptable from patient to patient. User-input through a Graphical User Interface(GUI), displayed on touch screen module, will act as control signals. It is in response to these signals that the breathing cycle will adjust. Alarms will be generated in response to anomalous input or system constraints out of range input or low battery. Ours is a conscious choice and a deliberate policy to build a tool that helps our masses take a collective step towards greater relief, less suffocating breaths and a selfrealization of the right to a dependable future. We are looking to build a portable ventilator with all necessary features to provide a locally possible, low cost solution to ensure no man dies of suffocation.

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