WiFi & Bluetooth Sensor Node

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:
  1. Set board size/stackup and move into PCB placement.
  2. Place U1 at the board edge with antenna keepout and U4 away from heat sources.
  3. Route power, buck, I2C, SWD/UART, and USB-C protection paths.
  4. Assign final passive MPNs and run full DRC/manufacturing checks.
Place route and MPNs
Start PCB placement
Assign passive MPNs
Route the PCB
Run full review

Demo Complete

The demo is finished. It didn't use any ACUs. You can now continue working with this project like normal.

D1
J1
U1
U2
U1 GND_16 - C9 P2
GND
GND
U4 VSS - C15 P2
U2 GND - U2 EP
GND
C3 P2 - C4 P2
U2 GND - U2 EP
U2 GND - U2 EP
U3 CTRL5 - R3 P2
SW1 GND - C17 P2
SW1 GND - C17 P2
U4 VSS - C15 P2
GND
GND
GND
U2 GND - U2 EP
C5 P2 - C6 P2
C16 P2 - SW1 NO_1
U1 GND_16 - C9 P2
C3 P2 - C4 P2
GND
C3 P2 - C4 P2
U1 GND_16 - C9 P2
U4 VSS - C15 P2
C5 P2 - C6 P2
SW1 GND - C17 P2
GND
C16 P2 - SW1 NO_1
U1 GND_16 - C9 P2
C5 P2 - C6 P2
C16 P2 - SW1 NO_1
GND
U1 GND_16 - C9 P2
U1 GND_16 - C9 P2
C5 P2 - C6 P2
SW1 GND - C17 P2
U3 CTRL5 - R3 P2
U2 GND - U2 EP
GND
GND
U1 GND_16 - C9 P2
U3 CTRL5 - R3 P2
GND
GND
GND
C3 P2 - C4 P2
GND
GND
U3 SW - L1 1
J1 VBUS__1 - U2 IN
U2 EN/UVLO - R5 P2
L1 2 - U3 OUT1
U1 POC_OUT - R13 P1
U2 OUT_1 - U2 OUT_2
J1 CC2 - R2 P1
J1 DP1 - J1 DP2
U2 IMON - R15 P1
L1 2 - U3 OUT1
U2 OUT_1 - U2 OUT_2
J1 CC1 - R1 P1
J2 2 - U1 JTAG_TMS_SWDIO
L1 2 - U3 OUT1
U4 SCL - U1 ULP_GPIO_1
J2 7 - U1 GPIO_8
U1 POC_OUT - R13 P1
J1 VBUS__1 - U2 IN
U2 ILIM - R3 P1
J1 DP1 - J1 DP2
U1 RESET_N - R12 P2
L1 2 - U3 OUT1
L1 2 - U3 OUT1
U2 EN/UVLO - R5 P2
L1 2 - U3 OUT1
J1 VBUS__1 - U2 IN
U2 ~{FLT} - R7 P1
U1 FLASH_IO_VDD - C14 P1
U1 ULP_GPIO_8 - R11 P1
R14 P2 - SW2 COM_1
J1 DN1 - J1 DN2
J2 8 - U1 GPIO_9
U2 DVDT - C2 P1
U1 RESET_N - R12 P2
U1 POC_IN - R13 P2
U3 PG1 - R8 P1
U1 POC_IN - R13 P2
J1 VBUS__1 - U2 IN
L1 2 - U3 OUT1
R11 P2 - LED1 A
U1 POC_IN - R13 P2
U2 OVP - R6 P2
U1 JTAG_TDO_SWO - J2 6
L1 2 - U3 OUT1
J1 VBUS__1 - U2 IN
J1 CC1 - R1 P1
J1 CC2 - R2 P1
U1 ULP_GPIO_8 - R11 P1
U3 PG1 - R8 P1
J1 DP1 - J1 DP2
U1 RESET_N - R12 P2
U3 OUT2 - C8 P1
U1 RESET_N - R12 P2
U4 SCL - U1 ULP_GPIO_1
J1 VBUS__1 - U2 IN
U2 OUT_1 - U2 OUT_2
J1 VBUS__1 - U2 IN
R14 P2 - SW2 COM_1
J1 DP1 - J1 DP2
U1 JTAG_TDO_SWO - J2 6
U2 OVP - R6 P2
J2 8 - U1 GPIO_9
J1 DN1 - J1 DN2
U2 ILIM - R3 P1
L1 2 - U3 OUT1
U1 JTAG_TDO_SWO - J2 6
J1 VBUS__1 - U2 IN
L1 2 - U3 OUT1
U2 EN/UVLO - R5 P2
L1 2 - U3 OUT1
U1 FLASH_IO_VDD - C14 P1
U2 OUT_1 - U2 OUT_2
J1 VBUS__1 - U2 IN
U2 OUT_1 - U2 OUT_2
J1 DN1 - J1 DN2
U4 SDA - U1 ULP_GPIO_0
U3 PG1 - R8 P1
J1 VBUS__1 - U2 IN
U3 VIN2 - C4 P1
U3 OUT2 - C8 P1
J1 CC2 - R2 P1
L1 2 - U3 OUT1
L1 2 - U3 OUT1
U3 VIN2 - C4 P1
L1 2 - U3 OUT1
U3 VIN2 - C4 P1
U2 DVDT - C2 P1
U2 ~{FLT} - R7 P1
L1 2 - U3 OUT1
U4 SDA - U1 ULP_GPIO_0
J2 7 - U1 GPIO_8
U2 OUT_1 - U2 OUT_2
J2 4 - U1 JTAG_TCK_SWCLK
J1 CC1 - R1 P1
U2 IMON - R15 P1
U3 SW - L1 1
L1 2 - U3 OUT1
U4 SCL - U1 ULP_GPIO_1
L1 2 - U3 OUT1
L1 2 - U3 OUT1
J2 4 - U1 JTAG_TCK_SWCLK
R14 P2 - SW2 COM_1
U2 OUT_1 - U2 OUT_2
U1 POC_IN - R13 P2
R11 P2 - LED1 A
L1 2 - U3 OUT1
U4 SDA - U1 ULP_GPIO_0
J1 DN1 - J1 DN2
J2 2 - U1 JTAG_TMS_SWDIO
U2 OVP - R6 P2
U2 ~{FLT} - R7 P1
U1 POC_IN - R13 P2
R1
Resistance
5.1kΩ
C4
Capacitance
10µF
C17
Capacitance
1nF
C7
Capacitance
100nF
C3
Capacitance
10µF
C5
Capacitance
10µF
R13
Resistance
100kΩ
R4
Resistance
100kΩ
U3
R7
Resistance
100kΩ
D2
C13
Capacitance
100nF
C2
Capacitance
10nF
C15
Capacitance
100nF
U4
R10
Resistance
10kΩ
D4
L1
C8
Capacitance
1µF
R15
Resistance
19.1kΩ
R3
Resistance
88.7kΩ
R14
Resistance
100Ω
C14
Capacitance
1µF
SW1
C9
Capacitance
10µF
SW2
LED1
R2
Resistance
5.1kΩ
C10
Capacitance
100nF
R8
Resistance
100kΩ
R9
Resistance
10kΩ
R6
Resistance
39.2kΩ
J2
C1
Capacitance
1µF
R11
Resistance
1kΩ
C16
Capacitance
10nF
C6
Capacitance
10µF
C12
Capacitance
100nF
D3
R12
Resistance
10kΩ
C11
Capacitance
100nF
R5
Resistance
464kΩ

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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


ModuleMPNTechnologyFrequency BandAntennaNotes
U1SIWG917Y111MGABARWi-Fi 2.4 GHz 802.11 b/g/n/ax + BLE 5.42.4 GHz ISMIntegrated antenna variantMust 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

USB-C WiFi BLE TH Sensor

USB-C WiFi BLE TH Sensor thumbnail
Consumer USB-C powered environmental sensor node with Wi-Fi, BLE 5.x, digital temperature/humidity sensing, protected 5 V input, and a 3.3 V low-power MCU/sensor rail.

Properties

WiFi

USB-C

Consumer IoT

5

V

Bluetooth

Pricing & Availability

Distributor

Qty 1

Arrow

$4.08–$6.83

Digi-Key

$0.00

HQonline

$3.72–$3.82

LCSC

$5.53–$5.70

Mouser

$26.67

TME

$1.00

Verical

$4.43–$8.13

Controls