156B Week 2

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

• • Individual analysis of components finished

• Designed and built the proposed circuitry design

• Wrote the code to run the LEDs to control duty cycle and intensity with PWM

  • Tested all the components together with code

Accomplishments from Previous Week

• • Circuitry works well with calculated resistors, MOSFET, and voltage regulatr

  • Working code, can control duty cycle and intensity

  • Battery performs well for what we need

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

• • Complete required sections of the report (Noor, Jen, Simon, Nick)

    • Background

    • Review of Existing Solutions

    • Statement of Requirements

    • Deliverables

    • Title page

    • Appendix with Individual Component Reports

  • Continue testing circuit (Noor, Jen, Simon, Nick)

    • Use optical meter to test intensity of LEDs at different duty cycles and current

  • Measure heat dissipation across the LEDs (Noor, Jen, Simon, Nick)

    • Test how hot they get when running at 100%

  • Order MOSFETs, Resistors/Pots, Battery, Voltage Regulator (Jen)

    • Need to decide the specific components to order

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

• We clarified the specific parameters for the frequency range of the bursts, duty cycle, and intensity (4/7/14 in person)

  • Maximum parameters: 75 Hz, 90% DC, 15 Hz burst freq and 100% DC

• LEDs are most likely running at 700 mA+, though it could shorten the life of the LEDs/change the wavelength. It seems as though the wavelength doesn't change enough to affect neuronal response. (4/8/14 by email)

  • Action: Run LEDs at 700 mA instead of 350 mA

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

• • Research programmable power supply, oscillator chips, voltage regulator (4/2/2014 in person)

    • Actions: researched programmable power supply, found out that it's not a practical solution - too bulky, expensive, and needs to be plugged into an outlet

    • Don't necessarily need the oscillator chip because our circuit seemed to work fine with the frequencies that we tested, but will research more if we need to use it

    • We are going to use a voltage regulator

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

• • Talked to Jeremy Orosco (4/4/14 in person)

  • Motor shield, Version 2, adafruit, bluefruit link

  • Arduino MATLAB support, create Arduino object

Risks and Areas of Concern

• • Heat from resistors, voltage regulator, and LEDs

• Implementing all of the components together

• Receiving parts quickly

• Designing PCB

Resources or Information Required but not Available

• • N/A

Schedule

• • Describe upcoming milestone

  • Update Gantt chart.

Budget (list amount spent and amount remaining)

• • $188.86 spent, $2,811.14 remaining

Progress on Report and Webpage

• • Updated Week 2 Progress Report

  • Finished and posted Individual Component Analyses

  • Will have report draft on website by Friday