Overview of Status of Analysis, Design, Fabrication, Tests, etc.
This was a big week for team 6! The first revision of the PCB and all surface mount components came in on Friday. Assembly of all components as well as 3D printing the first revision of the enclosure occured over the weekend. Following assembling, the PCB was tested for shorts; once cleared, component analysis was done on the assembled board using the beaglebone black. Major strides were made in the development of the code used by the beaglebone to test mux switching, ADC performance, battery management, and current source operation. The code developed went through many iterations, each of which eliminated inefficiencies and implemented more effective techniques to switch GPIO pins (found a library that memory mapped to gpio registers). Testing revealed issues with the switches used for configuring the current source, they will not be used in the final design and alternate switches have been ordered. Manual switches were soldered to the PCB to allow testing to continue. Another issue that arose was the beaglebone not consistently booting when running on battery power alone. The root cause of this concern was that the adafruit 1000c boost board was unable to deliver power fast enough to all components upon startup causing the beaglebone to go into a brownout state. Adding a capacitor to the 5v rail where the beaglebone receives power from the boost board rectified this concern. The final issue discovered from testing the assembly was a bottleneck in the sampling speed being caused by the ADC, this was found to be strictly a software issue and work is still being done to find a solution.
Accomplishments from Previous Week
Development of codebase for project (see github for progress)
Incorporated library for fast GPIO switching (~3MHz)
Wrote libraries for ADC interfacing and project specific functions.
Developed scripts for testing specific components.
Picked up finished PCB and soldered all components.
Successfully diagnosed and solved several board issues:
Current source switching
Power management
Designed first revision of outer housing and 3D printed
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Continue development of code for verification and validation (Max, Jacob, Matthew)
Develop code for data storage
Implement ADC buffer for faster reading
Modulate code further
Complete design of second PCB prototype and kick off(All)
Access accuracy of system with bench top equivalent system(All)
CAD iteration (Aaron)
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
(4/30/18) - Ken wants to see a live demonstration of the system for a 16 node configuration.
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
(4/25/18) - Jerry discussed forms of analysis appropriate for the scope of our project. Wants to see further battery power analysis
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
None at this time
Risks and Areas of Concern
Hitting 10 Hz sampling speed for all nodal configurations(limited currently by ADC speed)
Multi-threading data storage
Resources or Information Required but not Available
ADC driver buffer function
Schedule
Sometime next week: Video call with Ken
Wednesday 5/9/18: Group meeting with Jerry and Pedro
Budget (list amount spent and amount remaining)
$0 spent
$597.50 Remaining + $600 of shared shop expenses
Progress on Report and Webpage
Added standards to report
In processes of adding to webpage (assembling graphics)
Documents and files are updated after each working day