ESP32-S2-AIR780EX

The design requirement
training project needs a server gateway to control the lighting system of the relay section. Note that there are many voltage and current regulation protection components, but these were removed by the teacher because it was a training assignment.

The schematic design instructions

for the Air780EX4G module require a voltage of 3.8V to 4.2V. The corresponding power conversion design is available in the Air's hardware design documentation. This is from a training assignment; for convenience, I used leftover 1N4148 diodes from making a mechanical keyboard to achieve 3.8V through diode voltage drop (the voltage drop of a single 1N4148 straight diode is approximately 0.6V, depending on the diode's datasheet). All the surface-mount packages I used are 0805, except for the 1N4148 diodes.
Note that because this was just a training assignment, the school provided limited components. There was originally grounding protection, but the teacher removed it after reviewing my design. There are also four Zener diodes; add them according to your needs.
The PCB design instructions

and physical demonstration notes:

I forgot that the ESP32S2 has a full-featured USB module when I was drawing the schematic, but I remembered it while soldering. If you want to use this full-featured module... You can add another 5V header pin below the USB-D pin when drawing the diagram; this will create a solder hole when printing. Alternatively, you can add a Type-C female connector. Slightly adjusting the grounding pin position should be sufficient. When I was doing this practical assignment, the teacher provided a tantalum capacitor instead of a 10nF capacitor, which has positive and negative terminals. No
precautions .