Temperature and Humidity Sensor Node Design
Placed components
2:56
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
0:03
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
Waiting for input
Refine this doc
Ask about this doc
Firmware Pin Map — ESP32-S3 Environmental Node
MCU
ESP32-S3-WROOM-1-N16R8, powered from 3V3.
Pin assignments
| 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.
Welcome 👋
Flux helps you build PCBs faster with an AI teammate!
Create your account to collaborate, stay updated, fork your own version, and get instant answers from our AI agent.