Auto Recording Voice Recorder Design

flux

0:00

Work completed:
  • All schematic components were placed and configured (ESP32-S3, MEMS mic, microSD, USB-C, buck regulator, ESD/TVS diodes, LED, button, decoupling/bulk caps, CC pull-downs).
  • All nets wired: power rails (VBUS→buck→3V3→ESP32/peripherals), USB D+/D– through TVS, I2S (BCLK/LRCLK/DATA), SDMMC (CLK/CMD/D0–D3), CC1/CC2 pull-downs, LED and button controls, decoupling caps on every rail.
  • Schematic reviewed: capacitor/resistor ratings set, footprints verified, part availability confirmed, EMI/ESD protection validated.
Outstanding tasks (not done):
  • PCB stackup configuration (Standard 4-layer)
  • Inner copper layer power planes (3.3 V, GND)
  • Ground pours on all layers
  • Mounting hole placement considering mechanical constraints
  • Net classification and trace-width rule setup
  • Component placement on PCB outline
  • Auto-routing of USB differential pairs and other signals
  • Final ERC/DRC on layout
Success criteria status:
  • Schematic meets all requirements for functionality and protection ✅
  • PCB layout is partially prepared but not yet complete (stackup, placement, routing pending) ⚠️
  • Firmware and MP3/VAD/upload functionality still to be implemented (outside schematic scope)
Next recommended step: Proceed to the PCB layout phase in Flux:
  1. Set up the board stackup (Standard 4-layer) and configure inner power/GND planes.
  2. Enable ground pours on relevant layers.
  3. Place components within the 70 mm×50 mm outline, respecting antenna keep-out and mechanical constraints.
  4. Define net classes and trace-width rules before auto-routing.
149 days
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    USB-C Powered Wi-Fi Voice Recorder

    Properties

    USB

    microSD card (removable)

    RoHS

    WiFi, USB

    Digital MEMS microphone with I2S interface powered from 3.3V rail.

    Buttons, Display

    3.3

    V

    solderpad.org/licenses/SHL-2.1/

    Random Chocolate R2-D2

    Consumer Electronics

    USB-C powered Wi-Fi voice recorder based on ESP32-S3 with I2S MEMS microphone and microSD storage.

    Diagram
    


  
    
  
  
    
  



Controls and Indicators


















ESD TVS














USB-C Receptacle
VBUS node_5V
5V to 3.3V Buck Regulator
3.3V Power Rail
ESP32-S3-WROOM-1
USB D+ D-
Wi-Fi
MicroSD Card Socket
I2S MEMS Microphone
Microphone Power
SD Card Power
GND
Status LED
Pushbutton

    ESP32-S3-WROOM-1

    10

    Arduino

    USB-C 5V input with ESD protection on VBUS, buck regulator down to 3.3V rail powering ESP32-S3, I2S MEMS microphone, microSD card socket, status LED and button.

    Pricing & Availability

    Distributor

    Qty 1

    Arrow

    $0.82–$0.92

    Digi-Key

    $0.81–$1.52

    LCSC

    $1.34

    Mouser

    $1.30

    TME

    $0.91

    Verical

    $0.73–$0.92

    Controls