I haven’t modified the project yet in this session. The project is still effectively empty, so the work remaining is the full design.
Planned design scope for your node:
USB-C 5 V sink input using default current advertisement
Input protection stage covering reverse protection, OVP, UVLO, and OCP, sized for 0.5–3 A source capability
Ultra-low-power Wi‑Fi + Bluetooth MCU, likely an ESP32-class low-power device with 2.4 GHz 802.11 b/g/n + BLE 5.x
Digital temperature/humidity sensor
3.3 V power tree with regulator and datasheet-required passives
Proper decoupling, boot/config resistors, programming/debug access, and consumer-oriented connector/protection details
What remains to be done:
Select the exact MCU and T/RH sensor from datasheets.
Do a power budget and size the USB-C power-path and 3.3 V regulator correctly.
Capture the complete schematic, including USB-C CC resistors, protection ICs/FETs, regulator, MCU support circuitry, and sensor wiring.
Verify all ICs against datasheet reference circuits.
Run electrical review and clear all violations.
Then, after your confirmation, move to PCB layout.
Recommended architecture:
MCU: ESP32-C6-MINI-1 or ESP32-C3-MINI-1 depending whether you want BLE 5.x plus Wi‑Fi with strongest low-power ecosystem preference; C6 gives newer radio support, C3 is simpler and mature.
Sensor: Sensirion SHT41 or TI HDC3020 for low-power digital T/RH sensing.
Power: USB-C receptacle as 5 V sink only, CC1/CC2 5.1 kΩ Rd, followed by dedicated 5 V protection/power-path stage, then a low-Iq 3.3 V regulator.
Protection: eFuse / protection controller preferred over discrete-only approach for consumer robustness.
Since I’m blocked from executing changes right now, the next step is for me to build the schematic around one of these two directions:
Conservative/mature: ESP32-C3 + SHT41
Newer platform: ESP32-C6 + SHT41
If you want, I can proceed with the conservative ESP32-C3 + SHT41 architecture as the default when execution is available again.
Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portal
General Purpose Thick Film Standard Power
and High-Power Chip Resistor
47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film
Features:
- RMCF – standard power ratings
- RMCP – high power ratings
- Nickel barrier terminations standard
- Power derating from 100% at 70ºC to zero at +155ºC
- RoHS compliant, REACH compliant, and halogen free
- AEC-Q200 compliant