• Ported Pressure Sensors
  • Pressure sensor 1 is connected in the main tubing line using a t-splitter while sensor 2 is connected to the side hole of the manufactured cup.
  • One pressure sensor was integrated in Phase 4, while the second was integrated in Phase 5.
• Controllable Solenoid Valves
  • The team planned to implement controllable solenoid valves to have a way to safely release the built up pressure automatically from the DAQ, but were not able to obtain them due to purchasing and shipping difficulties.
  • Instead, the team decided to move forward with manual valves in Phase 5 to achieve the same purpose.
    • If another team continues the work of the project, controllable solenoid valves should be included as an update.
• Peristaltic Pump
  • The final piece to completing the beta prototype was a more advanced peristaltic pump
    • This pump should include rpm or flow rate control and a greater accuracy of power draw compared to our alpha-prototype.
    • Having an exact rpm or flow rate is vital to the testing and operation of the end product. When the team has access to exact flow rates, it presents greater possibility to accurately characterize the mechanical properties of the skin.
  • Issues relating to COVID-19 delayed the arrival of this advanced pump.
    • It is currently on purchase order and the team should have the pump integrated before the innovation expo as well as the Phase 6 deliverables.
• Integration Plan
  • To integrate the new elements, the team focused on adding one part at a time.
    • The code was first improved and Raspberry Pi implemented rather than Arduino.
    • This allowed for the second pressure sensor to be added. Challenges were previously faced using Arduino and both pressure sensors
    • Once the pressure sensors were able to collect data, they were attached physically in the system, focusing on cup integration
    • Lastly, the manual valve was included
  • Verification testing occurred after each integration to make sure components were functioning properly before increasing system complexity.
  • Final system tests were performed for validation.
• Testing/Evaluation Plan
  • In this phase, the team tested the functionality of their fully integrated system. The aim of this test was to test the data collecting capabilities of the device and the consistency of the results it provided.
    • In particular, the team was looking at the repeatability of the experiments and the difference between the pressure readouts at 1 mm deformation.
  • The test was performed by turning on the DAQ and turning the pump on at full power, which provides an approximately 40 mL/min flow rate.
  • The probe was placed on the testing individual’s forearm and data was collected for 5 seconds. After this time, the cup was taken off the forearm. This test was repeated an additional two times to provide an opportunity for a comparison of consistency between the results.

These areas of focus helped continue the prototyping process and develop a more complete system than was present in phase 4. This integrated system provides the ability for more accurate future testing and the optimization of a model to calculate mechanical properties of the skin.