Digital Audio Recorder

Overview

• Audio recorded by a pair of I2S MEMS digital microphones

• All recorded audio saved on removable microSD card on the PCB

• Board controlled by ESP32-S3-WROOM-1-N4, which should stream data over Wifi and/or Bluetooth

• Power supplied over USB-C or connected Li-Ion battery

  • Battery is automatically recharged to a safe level

Bill of Materials (BOM)

Logical Block Diagram & Schematic

Sub-Schematics

Layout

Final Board + Outcomes

• Almost all components soldered onto board correctly

• Failed while attempting to solder on the VERY last component (USB-C connector)

• SD card mounting failure

• We tried everything we could to resurrect it

Outcomes + Lessons Learned

• What went right with the board?

  • Effective logical abstraction in the schematic

  • Carefully designed trace widths to complement current

  • Reduced size of board to be ultra-compact

  • Added 7 test pads for easy debugging

• What went wrong?

  • SD card reader upside down/inaccessible from a mistake in interpreting the datasheet

  • In-line USB-C (rather than surface mount) was a nightmare to solder and ultimately doomed the project

  • We got over excited with the heat gun and melted the plastic on the header pins/toggle switch