ESP32-S3 Mic Carrier Board Ended

# PCB Design Brief — ESP32-S3 Mic Carrier Board

## Overview

Carrier PCB for a distributed microphone array project.

The board accepts two plug-in modules:
1. **YD-ESP32-S3 44P dev kit (https://www.aliexpress.com/item/1005008752956562.html?spm=a2g0o.order_list.order_list_main.59.24cf18023nQ1Wy welded with atenna)** — plugged in via female pin headers
2. **INMP441 MEMS microphone breakout (https://www.aliexpress.com/item/1005010312315549.html?spm=a2g0o.order_list.order_list_main.53.24cf18023nQ1Wy )** — plugged in via a female header matching the module's connector

The board also provides:
- A **4-position DIP switch**
- A **decoupling capacitor** on the mic power supply line
- **Breakout pad rows** on the outer edges to expose all GPIO pins for future use

## Fixed Modules (do not substitute)

### 1. YD-ESP32-S3 44P Dev Kit

Reference datasheets found in https://mischianti.org/vcc-gnd-studio-yd-esp32-s3-devkitc-1-clone-high-resolution-pinout-and-specs/#pcb-size :

Key dimensions:
- Two parallel pin rows, **25.40mm center-to-center**
- **22 pins per row**, 2.54mm pitch (53.34mm total pin span)
- Board body: 57.15mm long, 27.94mm wide

The module plugs in from above, sitting on the female headers.

### 2. INMP441 Mic Breakout Module

Small round PCB (~18mm diameter) with an INMP441 MEMS I²S microphone.
Connector: **2×3 header, 2.54mm pitch within rows, 7.62mm between rows**.

Pin assignment (as labeled on the module):
```
Row 1: SCK WS L/R
Row 2: SD VDD GND
```

## Electrical Connections Required ESP32 PINS

```
3V3 Mic VDD ── decoupling cap (cap− to GND)
GND Mic GND, Mic L/R, DIP switch common (all 4 positions)

15 Mic SCK
16 Mic WS
17 Mic SD

10 DIP 1
11 DIP 2
12 DIP 3
13 DIP 4
```

DIP switch closed pulls pin to GND = logic 1. No external resistors needed.

All other ESP32 pins have no required connections on this PCB — they should be accessible via the outer breakout rows.

---

## Layout Constraints

- **I²S traces** (GPIO15/16/17 → mic SCK/WS/SD): keep short and clean; avoid 90° bends; no long parallel runs next to noisy signals.
- **DIP switch**: must be accessible with the ESP32 dev kit installed — do not place it under the module body.
- **Mic connector**: must be accessible with the ESP32 installed — place it outside the shadow of the module body.
- **Decoupling cap**: place as close as possible to the mic VDD pin.
- **Outer breakout rows**: one row per side, each pad connected by a short trace to the corresponding female header pin — all 44 pins broken out.

---

## Deliverables

1. **EasyEDA Standard** project file (preferred — enables one-click JLCPCB order)
2. **Gerber + drill files** (zip, JLCPCB format) as fallback
3. **BOM** with LCSC part numbers for all passive components and connectors
4. **PDF schematic**

Target fab: **JLCPCB 2-layer standard**, 1.6mm FR4, any finish, quantity 5. read less