What did you personally accomplish this week? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).
- This week, I iterated with Callum on the schematic for the sensor array. Initially, we were going to make a PCB that covered half of the entire sensing area. We would then use 2 of them to cover the entire surface. However, we found out that JLCPCB charges a large fee for PCBs larger than a certain size. So, we reevaluated and reduced the PCB to the size of 2 hexagonally stacked sensor rows.
- We also introduced decoupling capacitors between the VCC and GND for all of the Hall Sensors; on Professor Fedder’s advice.
- We are also contemplating whether we need to introduce pull-up and pull-down resistors at VCC and GND respectively, to make sure that the sensors are reading the same voltage values, reducing the need for calibration.
- I also completed the layout for the PCBs. We have two variants right now, one that has the capacitors as SMT components and the other one that has them as through-hole components. We are still trying to finish the cost analysis for the SMT vs. through-hole capacitors and are also trying to see if we can source them on campus, without having to purchase them.
- The most crucial aspect of the layout was ensuring the alignment of the sensors and making sure that the distance between them was correct, according to the range characterization I had done earlier in the semester. I also had to consider the physical obstructions that would be there when we mount the PCB on the underside of the desk surface. I also positioned the pin headers to be out of the way and easy to access.
- I am attaching the drive link for some of the layout images below. Note that I have not yet done the routing as I am waiting to do that till we have an internal design review for the schematic and make sure that the connections are 100% correct. The routing will take 45 minutes at most, so I am not worried about it. I will also be doing the routing for only one of the PCBs (either the one with the SMT or the through-hole capacitors)
- https://drive.google.com/drive/folders/1UKzUN_nZ_kdPh8fONkxHx-t0Cf490zzb?usp=sharing
Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?
- I think my progress as well as that of our team is on schedule!
What deliverables do you hope to complete in the next week?
- Finalize the PCB layout and conduct a design review for it – with our entire team and a couple of professors, if possible, because we really can’t afford to mess this PCB up. I would also like to order the PCBs later next week.
- Me and Callum will start working on the Arduino code for polling the sensors. We want to have it finished and reviewed by the time the PCBs arrive.
- I also want to start integrating the charger and its peripheral circuitry. I need to figure out whether or not I need to use a Kilowatt to monitor peak current or if I can figure out a way to tap the PCB and get the charging current data.