156B Week 3

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

• • Withdrew from the parallel LED design

  • Looking into current limiting circuit design. This new design was suggested by Manny, owner of San Diego Electronics Supply. (See Yu-Hung (Nick) Lin for schematic diagram)

  • Tested LEDs in series but did not get desired current due to inherent resistance in proto-boards. Will test the LEDs on a perfboard

  • Researching control of GUI from MATLAB

Accomplishments from Previous Week

• • Tested two groups of three LEDs in series with current limiting resistors

  • Code is written to run two groups of LEDs, but still needs modification

  • Researched Arduino MATLAB support. This was from talking to Team 16, Jeremy Orosco (4/14/14) in person

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

• • Must have circuit design for LED completed (Simon, Nick, Noor, Jen)

  • Battery selection must be completed (Simon, Nick, Noor, Jen)

  • Look into EAGLE software for PCB, if not complete mastery of the program, at least get the basic idea of how to operate the software (Nick)

  • Order the electronic parts (Jen)

    • resistor, transistors, battery, bluetooth/wifi add-on shield for Arduino

  • Continue to modify the code and incorporate the possible Graphical User Interface function in MATLAB to the Arduino (Jen, Noor, Simon, Nick)

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

• • Sponsor would like to test the optical power from individual LEDs using optical power meter (4/16/14 in person)

    • Action: code is written for input of different testing parameters

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

• • The design of LEDs in groups of three in parallel is wasting approximating 200% of the power (4/9/14 in person)

    • Action: After talking to Steve Roberts (4/15/14 in person) and Manny from San Diego Electronic Supply (4/15/14 in person), we are going to abandon the parallel LED design. We put the LEDs in series and instead of using a voltage regulator for each group of LEDs, we are going to control the current rather than the voltage by using transistors. This new circuit diagram still needs to be tested. 

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

• • Justin Chen: Look into shift registers for individual control of LEDs (4/9/14 in person)

  • Stephen Chun: Use a rubber block to block stray light from LEDs instead of 3D printing individual caps (4/9/14 in person)

Risks and Areas of Concern

• • Battery selection is still an issue due to new circuit design solution

  • Design PCB

  • Heat dissipation

Resources or Information Required but not Available

• • N/A

Schedule

• • PCB design is pushed back because we are unable to finalize on the circuit design. We would like to start designing the PCB ASAP

  • The next major milestone is to determine the heat sinking method as well as the method to keep neurons at physiological temperature

  • Update Gantt chart

Budget (list amount spent and amount remaining)

• • $211.93 spent, $2788.07 remaining

Progress on Report and Webpage

• • Updated Week 3 Progress Report

  • Finished and posted Individual Component Analyses

  • Updated report draft on website 

  • Will continue to update the report draft and impact on society by Friday