This week I finished soldering our PCB and conducted PCB testing. I also started working on integration with the Verilog team.
I conducted extensive PCB testing throughout the week. I checked continuity for every connection on the board, checked each pin was supplying the appropriate power level, and power level at every connection and ensured it matches the schematic.
I also powered the PCB to ensure things were functioning and found all but one LED was working. I fixed this by trying to resolder the PCB, however in doing so I accidentally ruined a pad of the LED. However, I didn’t realise this at first so I worked on figuring out if the issue was with a dead LED, dead shift register, or a power issue.
By checking continuity and power outrages throughout the traces along the path of the power -> LED -> resistor -> ground, I was able to isolate the issue to be a lack of connection around the LED, hence realizing the pads were ruined. I solved this by incrementally soldering bare wire between the connections I wanted (power -> LED and LED -> resistor) till all connections were verified by both tests and finally the LED started working! The benefit of all of this means I am confident in the rest of my connections due to all of the debugging I did.
This is an example of skills I have learned over this past semester – trial and error by practicing my soldering and circuitry skills. I also learned more skills by asking other capstone groups for advice if they had encountered similar situations, I would say that was one of the most beneficial learning experiences I had. I also had practice outside of Capstone with TAing 18-349 where I had plenty of practice on laying out / fabricating and soldering PCBs.
The only task I have left for the PCB is fixing the rotary encoder as I laid the order of the pins out backwards on the schematic accidentally. I looked into a perf board solution to remedy this, but ultimately decided on adding another right angled header to try and change the direction of the encoder. I will also work on our final presentation and documentation for our final few submissions.