Added and wired the core schematic blocks: ESP32-S3 MCU/audio controller, I2S MEMS microphone, trigger button, piezo beeper with MOSFET driver, USB-C LiPo charging input, LiPo connector, 3.3 V regulator, programming/debug header, and decoupling/passive support.
Configured a compact 35 mm × 35 mm rounded 2-layer PCB outline with wearable-oriented placement priorities and placed the components as a first-pass layout.
Success criteria review
✅ Critical schematic components are present and interconnected.
✅ Firmware behavior is documented: 5-second max recording, start beep on press, end beep on release/timeout.
✅ Wearable form-factor requirements and low-power/safety notes are documented.
⚠️ PCB layout is started, but the first-pass placement still needs manual cleanup due to the very dense 35 mm × 35 mm target.
❌ Production-ready ERC/DRC cannot be confirmed yet because routing/final layout cleanup remains.
Next steps
Continue with PCB layout cleanup: resolve placement spacing, consider moving passives to the bottom side or slightly increasing the board size, then route/autoroute and re-check ERC/DRC until clean.
Compact wearable necklace PCB that records a 5-second audio clip when a trigger button is pressed. The device emits an audible confirmation beep at recording start and a second distinct beep when recording ends on button release or after the 5-second maximum window.
Core functional requirements
Audio capture duration: 5 seconds maximum per trigger event.
Trigger input: momentary push-button.
User feedback: buzzer/beeper chirp on press/start and release/end.
Audio storage: on-board nonvolatile flash storage or MCU-integrated flash if capacity allows.
Debug/programming: accessible programming header.
Wearable and safety requirements
Necklace-friendly compact PCB target: about 35 mm x 35 mm with rounded corners and a cord/chain attachment hole area.
Low-profile, lightweight SMD components where possible.
Single-cell LiPo battery power with USB-C 5 V charging input.
Charge current selected conservatively for small wearable LiPo cells.
Use solid ground reference, local decoupling near every IC, and bulk capacitance on battery/3.3 V rails.
Avoid sharp board edges; use rounded outline and keep battery contacts mechanically protected.
Keep microphone acoustic port unobstructed and away from buzzer/mechanical stress.
Selected architecture
MCU/audio controller: ESP32-S3 module class for integrated flash, low-power modes, I2S/PDM audio support, GPIO, USB/programming support, and firmware ecosystem.
Microphone: digital I2S MEMS microphone.
Storage: MCU module flash is expected to be sufficient for one 5-second compressed or low-rate PCM clip; optional external flash can be added later if higher fidelity/multiple clips are required.
Beeper: small SMD buzzer driven through a transistor from an MCU GPIO.
Power: USB-C 5 V input, single-cell LiPo charger, LiPo battery connector, 3.3 V regulator for electronics.
Firmware requirements
Initialize GPIO button input with debounce.
Initialize digital microphone interface and storage buffer/file.
On button press:
Emit start beep.
Start audio capture.
Continue until button release or 5-second timer expires.
On button release or timeout:
Stop audio capture.
Save/finalize clip.
Emit end beep using a distinct tone or cadence.
Enter low-power sleep when idle; wake from trigger button.
Layout requirements
Board shape: compact rounded square/pendant form factor.
Place USB-C/charging edge-accessible.
Place trigger button at an accessible perimeter location.
Place microphone at an acoustic edge/opening away from buzzer.
Place buzzer near an edge but away from microphone port to reduce acoustic/mechanical coupling.
Place decoupling capacitors close to MCU, charger, regulator, and microphone supply pins.