Hello there! I'm Karol, and I've embarked on the journey of automating my gardening beyond mere experimentation. I've drafted a PCB design, although I must confess, it's a tad messy. Before investing in components and PCB fabrication, I'm seeking validation that I'm on the right path.
The PCB integrates two MCP3008 and MCP23017 chips. The MCP3008 manages temperature sensors, while the MCP23017 controls servos/relays. Both chips are powered by an external 5V supply. I've included TVS diodes on both the external 5V line and the internal Raspberry Pi line, although I suspect the latter may be redundant. Additionally, I've added resistors to drop the supplied voltage to the chips to 3.3V, even though they can function at 5V, which might be unnecessary. To stabilize the 5V external line, I've inserted a few 100nF capacitors, albeit without extensive research. Zener diodes have also been added for extra stability.
Does this layout and design make sense? I'm open to any feedback or suggestions before I proceed further.
I have included ZIP file containing KiCad project
Additionally, I've added resistors to drop the supplied voltage to the chips to 3.3V, even though they can function at 5V, which might be unnecessary.
I have included ZIP file containing KiCad project
Just an FYI, not everyone uses or has Kicad, if you want a broader input, if you post your schematics etc as JPEG or PDF no one will need specialist software to view what you post. Secondly resistors make poor voltage drops because their voltage linearly depends on current which can vary. If you want to drop from 5V to near 3.3V, use a couple of series diodes, they'll drop between 1.2V to 1.5V in normal operation, this is not a comment on whether it is desirable or not.