156B Week 9

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

• • Awaiting arrival of 3D printed enclosures (eached out to Ed Pogue about using his 3D printer; awaiting response)

  • Replaced commercial TED with Dr. Chen's TED

    • excellent performance in air, but still tuning for performance with skin contact

• Filter is working well individually, but performs not as well when R_load is replaced with actual TED

Accomplishments from Previous Week

• • Finished CAD of enclosures

    • Mockup built and tested for sizing

    • Sent CAD to be 3D printed

  • Current testing all done using battery power (same batteries that would be used in final)

  • Replaced commercial TED with Dr. Chen's TED in prototype

  • Purchased 3V battery cells; components arrived for RTD circuit

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• • Purchase clips to attach enclosures to waist (Kam)

  • Finalize method to lock enclosure lids and purchase necessary parts (Justin)

  • Draw a PCB schematic for future improvement (Justin)

  • Debug filter performance when connected with entire TED circuit (Jeffrey)

  • Replace thermistor circuit with 4-wire RTD circuit (Kam, Thomas)

  • Implement safety measures in code (Thomas)

    • i.e. don't let TED receive more than 200 mA

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• • Sponsor is available for the week 10 presentation on Monday 6/1 (5/17/20, via email)

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• • Consider relocating electronics enclosures off the armband to reduce bulkiness (5/18/20, via zoom)

  • Add holes to the enclosures to allow wires to go through (5/18/20, via zoom)

  • Round off edges of enclosures to reduce stress concentration (5/18/20, via zoom)

  • Think about how to attach TED such that both faces are not covered by the armband (5/18/20, via zoom)

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

• • Consider the effects of sweat on the armband material (5/18/20, via zoom)

Risks and Areas of Concern

• • Unsure about best way/mechanism to keep enclosure lids locked/closed

  • Unsure whether there are risks to passing different current directions through filter circuit (esp. non-electrolytic capacitor)

    • if not, PWM module may be unnecessary

Resources or Information Required but not Available

• • None

Schedule

• • Integrate everything into the armband and enclosures to test once 3D printed enclosures arrive

Budget (list amount spent and amount remaining)

• • Spent: $533.10

  • Remaining: $1466.90

Progress on Report and Webpage

• • Updated and submitted second draft of report and webpage