Testing and Verification

As with any design, several iterative testing steps were necessary to test and verify the functionality of our proposed design.  Below is the approximate progression of testing and verification:

I.   Preliminary Testing

After receiving the data acquisition and accelerometers, preliminary testing was necessary to determine whether the two separate systems were compatible.  As seen in the first picture to the right, a cellular telephone set to vibrate ring mode was utilized to simulate a relatively high frequency similar to that found of the high frequency ventilators.

II.  Shaker Testing

The mechanical engineering department vibration laboratory facilities were used to conduct some initial analysis as to what filtering techniques were necessary.  Following advice given by the accelerometer manufacturer, a low-pass filter was constructed.  A voltage regulator was also introduced to maintain a consistent 5 Volt supply to the accelerometer via two 6 V batteries in series.  The initial breadboard setup can be seen in the second picture to the right.

III. Hershey Plastic Test Lung

Realistic testing was necessary to encompass any variation in lung compliance and background noise from the ventilator.  Several test scenarios were used to simplify and pinpoint sources of error which will be considered for the final deliverable prototype.  The plastic lung also enabled the team to vary the flow into each of the two billows as seen in the third picture to the right.

IV. Neonatal Patient Testing

Upon successful completion of the design  project, the Neonatal PALL team intends to conduct testing on patient at Hershey's NICU.  One such patient on a high frequency ventilator during one of team's trips to Hershey can be seen in the fourth picture to the right.  Per Dr. Palmer's request, global changes will be recorded for significant time periods to help determine global changes in ventilator effectiveness and will be displayed in two displays: one showing real-time results and a second display to general trends.