156B Week 5

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

• • Testing of commercial TEDs in progress

  • Able to communicate with microcontroller via mobile app; currently developing functionality to manually send reference temperature to microcontroller

  • Received RTDs

Accomplishments from Previous Week

• • Able to control commercial TED to maintain a user-defined reference temperature

  • Able to communicate with microcontroller using a phone + mobile app (via bluetooth module)

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

• • Reanalyze model to make temperature controller able to hold constant temperature better (Justin)

  • Adjust code for replacement of thermistors with RTDs (Justin)

  • Update code to use reference temperature given by user via mobile app (Kam, Tom)

    • i.e. wrap existing controller code in bluetooth + app code

  • Test code when running purely off reference temperatures from phone (Jeffrey)

  • Compare RTDs vs thermistors (Tom)

    • response time, accuracy

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

• • The average metabolic heat flux through the skin should be approximated to 58 W/m^2 (4/23/20, via zoom)

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

• • Quantify risks (4/20/20, via zoom)

  • Try to amplify output for temperature range of interest when reading RTD voltage values (4/20/20, via zoom)

  • Look into a nonlinear model in time/frequency domain (4/20/20, via zoom)

  • Talk to sponsor for assumptions made in a person's heat flux and heat flux required for TED (4/20/20, via zoom)

  • Look at H-bridge circuit again (4/20/20, via zoom)

  • Incorporate a regulating pulse width modulator to lower inductance and capacitance requirements for filter (4/20/20, via zoom)

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

• • Look at electronic waste concerns and possible ways to mitigate (4/20/20, via zoom)

Risks and Areas of Concern

• • Commercial TEDs do not perform well when cooling without a heatsink; may need to design a homemade small heatsink

    • (but perform well when heating)

• Unsure how to verify accuracy of thermistors vs RTDs for comparison 

  • i.e. unsure what to use as a "true" temperature value

Resources or Information Required but not Available

Schedule

• • Describe upcoming milestone

  • Update Gantt chart.

Budget (list amount spent and amount remaining)

• • Spent: $340

  • Remaining: $1660

Progress on Report and Webpage

• • Added the "Applicable Standards" section to the report

  • Updated "Societal Impacts" and "Professional Responsibility" sections of the report