nRF5340 Wi Fi Sensor Node
Worked for 4 mins 26 sec
Implemented the schematic for the USB-C powered Wi‑Fi/BLE temperature/humidity node. It uses a SiWG917 Wi‑Fi/BLE 5.4 module, SHT41 T/RH sensor, USB-C sink input, TPS25940 true reverse-blocking eFuse with OVP/UVLO/OCP/soft-start, MP28301 3.3 V buck regulator, ESD protection, reset/ISP/SWD debug, I2C pull-ups, and status LED.
Created project files:
Open items:
- PCB layout/routing is not done yet, so airwire DRC errors are expected.
- Generic passives still need final manufacturer MPNs before manufacturing export.
- Layout must enforce the SiWG917 antenna keepout and thermal isolation around the SHT41.
Suggested next steps:
- Set board size/stackup and move into PCB placement.
- Place U1 at the board edge with antenna keepout and U4 away from heat sources.
- Route power, buck, I2C, SWD/UART, and USB-C protection paths.
- Assign final passive MPNs and run full DRC/manufacturing checks.
can you design using nrf5340 SoC ?
Thought for 5 sec
Yes. The current schematic uses the SiWG917 because the nRF5340 provides BLE 5.x but no Wi‑Fi. To retain your 2.4 GHz 802.11 b/g/n requirement, an nRF5340 design needs a companion Wi‑Fi IC/module—preferably the Nordic nRF7002 over QSPI/SPI.
Recommended revision:
- nRF5340 module/SoC for application processing and BLE
- nRF7002 module for 2.4 GHz Wi‑Fi
- Existing SHT41 I²C sensor
- Existing protected USB‑C → TPS25940 → 3.3 V power architecture, resized for both radios
- SWD, USB, crystals/decoupling, RF keepouts, and Nordic SDK/Zephyr firmware documentation updated accordingly
I cannot modify the project now because no ACUs are available. Once ACUs are available, the remaining work is to source exact Nordic parts, recalculate peak power, replace the SiWG917 block, rewire and verify the schematic, and update the project files.
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Technical Construction File — USB-C WiFi BLE TH Sensor
Status
Draft — schematic-stage regulatory file.
Applicable Regulations
- FCC Part 15 intentional radiator / unintentional radiator
- CE RED for EU radio equipment
- ISED Canada if sold in Canada
- UKCA if sold in the UK
- RoHS/REACH for consumer production
Product Description
USB-C powered indoor consumer temperature/humidity sensor node using a Silicon Labs SiWG917 Wi-Fi/BLE module and Sensirion SHT41 digital T/RH sensor.
Wireless Technology Summary
Table
| Module | MPN | Technology | Frequency Band | Antenna | Notes |
|---|---|---|---|---|---|
| U1 | SIWG917Y111MGABAR | Wi-Fi 2.4 GHz 802.11 b/g/n/ax + BLE 5.4 | 2.4 GHz ISM | Integrated antenna variant | Must follow Silicon Labs integration/keepout guidance |
Required Documentation Checklist
- Product block diagram — included in Project Specification
- Draft BOM from schematic — available in Flux BOM
- RF integration notes — included below
- Draft Declaration of Conformity — created in this file
- User manual outline — included below
- Final schematic PDF export
- Final PCB layout/Gerbers after layout
- Module certification grants and integration manual from Silicon Labs
- EMC/RF test reports from accredited lab
- Final product labels with FCC/CE/UKCA marking
RF Design Notes
- U1 must be placed at a PCB edge with the integrated antenna facing outward.
- Keep the antenna clearance void of copper, traces, vias, components, and metal on all layers.
- Keep U3/L1 buck regulator switch node and inductor away from U1 antenna region.
- Maintain solid ground under the module body where allowed by the module datasheet.
- Do not change the module antenna or add metal/plastic in direct contact with the antenna without RF validation.
Draft Declaration of Conformity
We, [Company Name], declare that the product USB-C WiFi BLE TH Sensor is designed to conform to applicable FCC Part 15, CE RED, RoHS, and EMC requirements when manufactured and integrated according to the final approved schematic, PCB layout, BOM, RF module integration guide, and user manual.
Authorized signatory: ____________________
Date: ____________________
User Manual Outline
- Product overview and intended indoor consumer use.
- USB-C 5 V power-only input requirements.
- Wireless setup/provisioning instructions.
- Temperature/humidity measurement limitations; avoid direct sunlight, condensation, and heat sources.
- Regulatory notices: FCC Part 15 statements, CE/UKCA marking, RF exposure statement, no user-serviceable RF modifications.
- Disposal and RoHS/WEEE notes.
Open Items
- Confirm exact SiWG917 certification IDs and approved integration conditions.
- Add final PCB layout screenshots/exports after layout.
- Run EMC pre-scan with USB cable attached and Wi-Fi/BLE active.
Status
Applicable Regulations
Product Description
Wireless Technology Summary
Required Documentation Checklist
RF Design Notes
Draft Declaration of Conformity
User Manual Outline
Open Items
