Temperature and Humidity Sensor Node Design

flux

Work done
  • Reconfigured the PCB to a Standard 2 Layer stackup while preserving the 50 mm × 50 mm board and 2 mm rounded corners.
  • Set the routing intent to top copper for signal/power and bottom copper as the primary reference/plane layer.
  • Re-placed the board for the 2-layer strategy: J1 at the left edge, U1 at the top antenna edge, U2 away from the power cluster, and D1/U3/U4 near USB-C input.
  • Updated the Implementation Notes with the 2-layer stackup, placement strategy, verification status, and remaining work.
Success criteria review
  • ✅ 2-layer stackup is configured and board dimensions are retained.
  • ✅ Component placement is optimized for USB-C access, ESP32 antenna position, power-path compactness, and sensor thermal separation.
  • ❌ Routing is not fabrication-ready yet: the latest check still reports 49 airwires, meaning copper routing remains incomplete.
  • ❌ Final fabrication readiness is blocked until routing is completed and the airwire check is clean.
Next steps
Complete PCB routing next, prioritizing USB D+/D−, VBUS/5V, 3V3, GND, and I2C, then re-run checks before export/manufacturing.
Route remaining nets
Run DRC check
Review placement bottlenecks
Add stitching vias
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USB-C ESP32 Environmental Sensor Node Specification
Goal
Design a low-power consumer environmental sensor node powered from USB-C 5 V. The node uses an ultra-low-power WiFi/BLE MCU module and a digital temperature/humidity sensor.
Architecture
Power path: USB-C receptacle VBUS -> input ESD/TVS + CC pull-downs -> eFuse/protection stage with reverse blocking, OVP, UVLO, and OCP -> protected 5V rail -> 3.3V regulator -> ESP32-S3 module and T/RH sensor.
Key Requirements
  • USB-C default 5 V sink behavior with 5.1 kOhm CC1/CC2 pull-downs.
  • Support USB-C source current range of 0.5 A to 3 A; local protection current limit selected around 1 A for this low-power node unless load budget changes.
  • 3.3 V rail for MCU and sensor.
  • Digital sensor interface over I2C.
  • RF-aware PCB placement: WiFi/BLE module antenna at board edge with keepout/overhang.
  • Protection: reverse polarity/reverse current blocking, OVP, UVLO, OCP, and VBUS ESD/TVS.
Implementation Notes
  • Prefer an ESP32-S3-WROOM class module for 2.4 GHz 802.11 b/g/n WiFi and BLE 5.x capability.
  • Prefer a low-power I2C temperature/humidity sensor such as SHTC3/SHT31/HTS221 depending on library availability.
  • Use a high-current-capable 3.3 V LDO or regulator with adequate input/output bulk and local decoupling.

    Goal

    Architecture

    Key Requirements

    Implementation Notes

Documents

    USB-C ESP32 Environmental Sensor Node Specification

    Implementation Notes

Assets

Assets are files uploaded to this project which can be used in various ways.

USB-C ESP32 Environmental Sensor thumbnail
Low-power USB-C 5V environmental sensor node with ESP32-S3 WiFi/BLE, digital temperature/humidity sensing, protected 5V input path, and 3.3V regulation.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor

Qty 1

Arrow

$3.00–$4.33

Digi-Key

$6.80–$8.01

HQonline

$1.43–$1.47

LCSC

$7.68–$7.74

Mouser

$11.36

TME

$1.33

Verical

$4.96–$5.26

Controls