Schematic Connection Check


Here are the highest-impact improvements I’d make:
  1. Fix known connectivity/layout issues
    • Connect SW13 to an intended ESP32 GPIO.
    • Clear the remaining PCB airwires and dangling traces.
    • Re-check that power and GND are actually routed, not just schematic-connected.
  2. Improve the power system
    • Replace or thermally review the AMS1117; it may dissipate too much heat from USB 5V to 3.3V with ESP32 + audio load.
    • Consider a small buck regulator instead.
    • Correct the suspicious C1 = 1F value.
    • Add/verify proper regulator input/output bulk caps close to U2.
  3. Harden ESP32 boot/reset
    • Add a defined pull-up on IO0 if the boot button pulls it low.
    • Keep EN pull-up and reset cap values intentional.
    • Decide whether RXD0/TXD0 should be exposed for debug/programming.
  4. Improve USB-C robustness
    • Add ESD protection on USB D+/D−.
    • Add a fuse/polyfuse or current limiting on VBUS.
    • If USB data is used, route D+/D− as a short matched differential pair.
  5. Fix WS2812B logic margin
    • Since the LED is powered from 5V but driven by 3.3V ESP32 logic, add a level shifter or power the WS2812B from 3.3V.
  6. Improve audio performance
    • Place MAX98357A decoupling caps very close to its VDD pins.
    • Keep speaker traces short/wide and away from antenna/USB data.
    • Confirm speaker impedance/power is compatible with the amp and 3.3V supply.
  7. ESP32 layout/antenna
    • Enforce the ESP32 module antenna keepout: no copper, traces, or components under/near the antenna region.
    • Put 3.3V decoupling close to the module power pins.
    • Use a solid GND plane with short return paths.
  8. Manufacturing polish
    • Clean up schematic label overlaps for readability.
    • Add test pads for 5V, 3V3, GND, EN, IO0, USB D+/D−, and key I2S/audio signals.
    • Add board revision/date/silkscreen labels.
    • Run ERC/DRC again after routing.
Fix and review issues
Fix SW13 connection
Improve power supply
Clean PCB routing
Add USB protection
Create test points

Schematic of CardSynth v2
IC1
Manufacturer Part Number
MAX98357AETE+T
R5
Resistance
100kΩ

CardSynth v2

CardSynth v2 thumbnail