[For educational purposes only. Not for human use.]
My goal here is to build a low cost, computer-controlled (rather than pneumatically-controlled) prototype ventilator that could generate various waveforms used in the medical industry. Gas energy would be transmitted through an existing off-the-shelf patient interface.
This is a very basic explanation of what I'm working on.
Step 1: Software
I worked with software for rapid prototyping to get the idea together. The attached image shows some Ruby code I was able to integrate to build my own interface.
The interface has an oscilloscope configured to read in cm/H2O (i.e. pressure) and includes user-selectable pneumatic/monitoring controls. It will be updated to include more waveform controls, but for now it is configured as a therapy device.
I'll eventually be moving towards enbedded harware, so in the event of a shutdown, the user is still able to manipulate physical controls on a board without the need of a separate computer.
Step 2: Hardware...
I coupled the IC board with solid-state relays and a power supply for controlling pneumatic valves. Valves were sized for volumetric flowrate which will be fine-tuned down the road.
The patient interface is from an IPV machine that we had already owned. See the embedded video above to see a test run.
[All steps posted under Creative Commons License]