Temperature and Humidity Sensor Node Design
Thought for 2 mins 56 sec
Placed 27 component(s): U1, C3, C6, C7, H3, H2, J1, R5, C5, R2, H4, U4, C2, R3, R1, C4, U3, R7, J2, H1, R9, U2, R6, R8, R4, C8, C1
Thought for 3 sec
Work done
- Built the schematic for the USB-C powered Wi‑Fi/BLE temperature/humidity node: ESP32‑S3 module, SHT31 sensor, USB‑C default-sink input, TPS25200 protection, AP2112 3.3V regulation, decoupling, I²C pull-ups, boot/reset, USB data, and UART debug access.
- Configured a compact 50 mm × 50 mm 4-layer PCB setup and placed all components with USB‑C at the edge, ESP32 antenna facing outward, sensor away from the power section, and mounting holes in the corners.
- Added documentation: Project Specification, Firmware Pin Map, and Design Review Results.
- ✅ Complete protected USB-C power-path schematic and 3.3V rail are present.
- ✅ Dual-radio MCU, digital T/RH sensor, support passives, and debug/programming connections are integrated.
- ⚠️ PCB placement is complete, but final routed PCB production readiness is not complete yet.
- ⚠️ Final checks found remaining PCB routing airwires and one copper-overlap item that must be resolved before fabrication.
Route the PCB traces, inspect the copper-overlap item, then rerun final checks before manufacturing export.
Route remaining airwires
Inspect copper overlap
Run final review
Check antenna placement
Export production files
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Firmware Pin Map — ESP32-S3 Environmental Node
MCU
ESP32-S3-WROOM-1-N16R8, powered from 3V3.
Pin assignments
Table
| Function | ESP32-S3 pin | Net | Notes |
|---|---|---|---|
| I2C SDA | IO8 | I2C_SDA | SHT31 SDA, 4.7 kΩ pull-up to 3V3 |
| I2C SCL | IO9 | I2C_SCL | SHT31 SCL, 4.7 kΩ pull-up to 3V3 |
| SHT31 ALERT | IO5 | SHT_ALERT | Optional interrupt input |
| eFuse FAULT | IO4 | EFUSE_FAULT | Active-low open-drain fault input, 10 kΩ pull-up to 3V3 |
| USB D- | IO19 | USB_DN | ESP32-S3 USB Serial/JTAG / USB device |
| USB D+ | IO20 | USB_DP | ESP32-S3 USB Serial/JTAG / USB device |
| UART0 TX | TXD0 | UART0_TX | Debug header J2 pin 3 |
| UART0 RX | RXD0 | UART0_RX | Debug header J2 pin 4 |
| Reset/enable | EN | ESP_EN | Debug header J2 pin 5, 10 kΩ pull-up, 1 µF delay capacitor |
| Boot mode | IO0 | ESP_BOOT_IO0 | Debug header J2 pin 6, 10 kΩ pull-up; pull low for download boot |
Firmware initialization outline
- Configure I2C on SDA=IO8, SCL=IO9 at 100 kHz or 400 kHz.
- Initialize SHT31 at default address with ADDR tied low.
- Configure IO4 and IO5 as inputs with internal pull-ups disabled or enabled only if needed; external pull-ups are present for FAULT.
- Enable Wi-Fi 2.4 GHz and BLE 5.x services as required by application firmware.
- Use light sleep/deep sleep between measurements for low-power operation; keep USB power policy simple because the node is USB powered.
- Use USB Serial/JTAG or UART0 header for manufacturing programming and debug.
MCU
Pin assignments
Firmware initialization outline
