Our ventilator prototype has been up and breathing under software control for the past few days. We are working on tuning the control loops, testing different tidal volumes and patient conditions, and additional hardware/software integration tasks. In this video you can see several basic closed-loop pressure controlled breaths occurring. The control loop is not fully tuned yet, but we are still able to regulate the inspiratory pressure to around 40 cmH20 (this is very high for a patient scenario, but that's the test case where we took the video :) ) We regulate the patient pressure by rapidly varying the speed of our air blower, which has a very fast dynamic response. So far things are looking really good!