Subsystem Build & Test
Table of Contents
Team VisionThroughout the Subsystems Build and Test Phase, Team BASE has successfully produced:
- A 3D-printed Rev. 2 Prototype will all sensors integrated;
- Bluetooth 4.0LE implementation which transmits all data from the prototype to a generic mobile application; and
- Updated firmware which provides increased robustness and flexibility.
Rev. 2 Prototype
A revised prototype was designed and 3D-printed out of ABS (see Figure below).
This second prototype has undergone many improvements in the mechanical housing, including:
- Earbuds for stability;
- PPG integration that provides accurate SpO2 sensing;
- New environmental unit placement within the earbud to minimize heat transfer from the body; and
- Smaller microcontroller and battery housing for a more ergonomic design.
Due to time limitations, it was decided to place the PPG sensor behind the ear as opposed to within the ear. During MSD I, we performed initial sensor accuracy testing and demonstrated strong signal quality at this location due to good blood perfusion. This is a good example of risk mitigation, as we recognized early-on in the design process that the in-ear PPG may not be possible and, consequently, we explored alternatives locations during initial feasibility testing.
The main program was updated to increase robustness and efficiency as well as allow for Bluetooth streaming. Specifically, we have transitioned from a superloop architecture (one large while loop) to an event queue architecture (tasks occur as needed).
Throughout this phase, we were able to integrate Bluetooth Low Energy (BLE) into our design. Currently, all sensors are able to stream continuously to a generic mobile application. Next steps will include developing a custom app. The BLE Subsystem test plan can be found here.
Test Results Summary
All test plans will be completed and documented by the next design review (Week 10).
Risk Management & Problem TrackingWe did not need to update our Risk Management plan during this phase. Our problem tracking document can be found here.
Design Review Materials
Our 3 Week Plan Document can be found here.
To Be Completed by Week 10
- Final testing/documentation for all sensors;
- Full BLE capabilities and transmitting to a custom Android app; and
- A Rev. 3 Prototype that will fit all electronics into a compact design.
- Terry: Software improvements and BLE support
- Tegan: Final sensor testing/documentation
- Htet: Continue building/soldering PCBs
- Andrew: Design and print Rev. 3 prototype
- Alex: Develop custom Android application