Technical Construction File — USB-C WiFi BLE Environmental Node
Status
Draft, schematic-stage.
Applicable Regulations
FCC Part 15 intentional radiator integration using pre-certified module conditions.
FCC Part 15B unintentional radiator testing for the final product.
CE RED for EU wireless product placement.
ISED/UKCA may apply depending on target markets.
RoHS/REACH material compliance for consumer sale.
Product Description
USB-C powered consumer temperature and humidity node using an ESP32-C3-WROOM-02-N4 Wi-Fi/BLE module and SHT40 digital sensor.
Wireless Technology Summary
Table
Module
MPN
Technology
Frequency Band
Antenna
Notes
U3
ESP32-C3-WROOM-02-N4
Wi-Fi 802.11 b/g/n + BLE 5.x
2.4 GHz ISM
Integrated PCB antenna
Follow Espressif module integration and antenna keepout rules
Required Documentation Checklist
Project specification created.
Schematic-stage BOM available in Flux.
Firmware starter created.
Bring-up/test plan created.
Final PCB layout/Gerbers after placement/routing.
RF module certificate/grant evidence attached for the exact ordered module variant.
EMC/RF lab test reports for the finished product.
Final user manual and product labels.
RF Design Notes
Place U3 at a board edge with the ESP32-C3-WROOM-02 PCB antenna facing outward.
Keep the antenna keepout free of copper, traces, vias, components, batteries, USB cable routing, and enclosure metal unless Espressif explicitly allows otherwise.
Keep the buck converter, inductor, USB-C connector shell, and USB cable path away from the antenna area.
Configure firmware regulatory domain/channel plan for the intended market.
EMC/ESD Notes
D2 protects VBUS_RAW; D1 protects USB D+/D−. Place both close to J1 with low-inductance ground return.
U2 buck layout is the primary conducted/radiated EMI risk. Keep SW loop compact and avoid routing SW near USB D+/D−, SHT40, and antenna.
USB-C shield should be tied to board ground near the connector with stitching vias in the layout stage.
Draft Declaration of Conformity Placeholder
We, [Company Name], declare that the product USB-C WiFi BLE Environmental Node is designed for conformity with applicable FCC Part 15, CE RED, RoHS, and EMC requirements when manufactured and tested in its final enclosure.