Just designed my first "real" PCB that I plan to send out for manufacture in the next day or so. I've milled out a few on a 3018 CNC. I wanted to do this one that way as well, but realized it would have been a bear to make DIY and mostly THT wasn't the direction to go. So, this is my first mostly SMD PCB with standalone ATMEGA328P-PU on a PCB at least. I used Diptrace initially, but then switched over to EasyEDA since I plan to send it to JLCPCB for the best cost and all their components from LCSC have the included the PCB footprint. (Side note: I wasn't looking forward to switching at first, but the component selection with included pattern was a real treat with EasyEDA compared to Diptrace).
This should actuate servos to control water flow to "zones" based on the feedback from the sensors of soil wetness.
I am a complete novice to this, but I think that the design is close. I learn by doing and iterations, so here goes. I figured you guys love this stuff and it is second nature to you, so I am all ears for any general feedback, criticism, and design improvements in general that I will take to my future PCB design endeavors and use this one.
The PCB Layout:
the components on the right will be exposed from the enclosure for user feedback, and the JST XH connectors are for the sensors. There is a DC 5.5 x 2.1 plug for a 12V 1A DC adaptor in top left. Key 1 is a "test" button that I plan to use to prime this thing. SW1 is the power switch. The U components connect to sensors for feedback that will be evaluated in the code. The H headers are connected to servos that respond in accordance with the settings provided by R1, R2, R3. H4 is ICSP header for programming. P1 is the motor. I increased the mil trace to 15 mils for the power and ground lines. U2 is the 5V regulator.
Edits: Added ground plane, moved decoupling capacitors for the MCU closer to their point-to-point, added some decoupling capacitors to the adapter feed. Increased trace widths to 24 mils (same as via diameter). Removed interior mounting holes that were too close (shouldn't be needed).
Specific Questions / Schematics:
- Is 4 and 5 for SW1 like chassis grounds / PCB grounds? I can just leave them unconnected right?
- Do you see U2 having any issues with regulating the 12V 1A supply for the 5V Reg that is provided downstream to all the other applicable components? In breadboard testing, amperage never really exceeded 500mA, but since the supply could provided 1A, I chose a "larger" package regulator. MC7805BDTRKG - Datasheet
- Oscillation, Stabilization, and ICSP look correct?
- The test button will pull PD7 (Test Net Port) to ground when depressed right and 3, 1 can remain unconnected?
Thanks in advance!