Topaz
Radio module which can pressure, temperature and humitidy, and location
Total time: 9.5h
Day 1:
Today I worked on the schematic. I decided to use a SAMD21, an SX1262, and a BME280, as I have previous experience with them. I imported custom parts from Snap EDA and modified the (PE4257, and ESC32TXO).
Time spent:~2 hours
Day 2: The schematic is finished. I moved on to the PCB layout. I imported a custom oscillator (ECS-327TXO-2012) for the SAMD21. I'm quite happy with the design so far. I also revisited the schematic and added another button, which could potentially be used for Morse code input in the future. Time spent:~3 hours
Day 3: I changed the minimum track spacing to 0.127 mm to prevent copper pads from merging, in line with OSH Parkβs manufacturing limits. I also worked on minimizing the PCB size to help reduce production costs. Time spent:~2.5 hours
Day 4:
Final changes were added. Fixed certain errors in DRC. Fixed final arragment problems. I went back to KiCad and ran ERC to checked and fixed any errors.
I reviewed for a final time the schematic to see if I missed anything ( compared it with the manufactorers reference design and datasheets).
Time spent: 2 hours
Day 5:
I added a GPS module so that location can be transmitted. I added a ATGM336H with a passive antenna. I chose this module because it is a very cheap and affordable.
Time spent: 2 hours
Overall Notes: The biggest challenge I faced was figuring out the RF section. The manufacturer-recommended RF switch, the BGS12WN6E6327, is extremely small and nearly impossible to solder by hand. To resolve this, I decided to find a replacement and settled on the PE4259, which is considerably larger and easier to solder.