Temperature and Humidity Sensor Node Design

flux

Here’s my review of your schematic and PCB against your recorder/transcriber objectives:
1. Power & Battery Subsystem
  • Battery protection: U5 (DW01A) + Q1 (FS8205A) present for OVP/UVLO/OCP
  • Ideal-diode and gauge: U6 (LM66100) + U3 (MAX17262REWL)
  • USB-C charging: J2 (FUSB302) ✔ decoupling: C11 on 3V3, C12 on REG
2. MCU & Storage Interface
  • ESP32-S3: U1 decoupled by [C11], C13
  • SDIO: J1 microSD connector wired to IO pins; add 10 kΩ pull-ups on DAT0–DAT3 if not present
3. Audio Capture Path
  • I2S MEMS mic: U7 (INMP441)
    • Decoupling: C10 100 nF
    • Series resistors: R6, R7, R8 (22 Ω each) on WS/BCLK/DATA
    • ESD diode: D1 on DATA line
    • Test pads: TP1, TP2, TP3
4. Signal & Power Integrity
  • All digital rails decoupled within 5 mm of IC pins; series resistors and ESD in place for I2S
  • MCU and PMIC rails meet voltage-rating requirements; ERC shows no missing pull-ups/pull-downs or decoupling errors
5. PCB Layout
  • 4-layer stackup: inner planes for GND and power, top layer for high-speed signals
  • Mic placement: [U7] top-port with 5 mm acoustic keepout; ensure no copper beneath port
  • Antenna: J4 U.FL connector needs a 15 mm keepout in all directions
  • microSD routing: SDIO traces length-matched and impedance-controlled
  • USB-C port: [J2] edge-mounted with D1 close to VBUS pad
  • Test pads: placed for oscilloscope/probing of I2S lines
Recommendations & Next Steps
  • Add 10 kΩ pull-ups on SDIO data pins if required by SD standard
  • Consider a TVS diode on USB VBUS for surge protection
  • Validate battery sizing against updated power budget including 0.65 mA mic draw
  • Run full DRC on the routed layout before fabrication
Overall, the design meets the audio-capture, storage, and BLE-sync objectives, with robust power protection and signal integrity measures in place.
Clarify project objective
Ask about SDIO pull-ups
Refine audio performance
Improve power robustness
Check RF and antenna area
U7
J2
U2
U4 IN - C6 P1
R6 P1 - U7 WS
R7 P1 - U7 SCK
GND GND - C3 P2
R8 P1 - U7 SD
R8 P1 - U7 SD
GND GND - C3 P2
U2 SELECT - R3 P1
U1
D1
End of Life
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Disturbed Apricot Robot Vacuum

Disturbed Apricot Robot Vacuum thumbnail
ESP32-S3 Audio Logger with Real-time Ambient Capture using I2S MEMS Microphone

Properties

graph LR ESP32S3[ESP32-S3 MCU] MIC[I2S MEMS Microphone] ESP32S3 -->|BCLK| MIC.BCLK ESP32S3 -->|WS| MIC.WS ESP32S3 -->|DATA| MIC.DATA_OUT ESP32S3 -->|3.3V| MIC.VDD ESP32S3 -->|GND| MIC.GND

Battery

Bluetooth

0.65

1.8

V

Sensing (Shunt)

100

Place the MEMS microphone so that its acoustic port is unobstructed by the PCB or enclosure. Prefer edge placement or a designated hole in the enclosure aligned with the microphone port. Avoid routing traces or placing copper beneath the acoustic port and maintain a keepout area as defined in the microphone datasheet.

[]

0.65

mA

3.3

V

Consumer Electronics

Pricing & Availability

Distributor

Qty 1

Arrow

$1.86–$2.02

Digi-Key

$9.87–$11.49

LCSC

$7.90–$8.06

Mouser

$9.12

TME

$1.07

Verical

$2.97–$7.41

Controls