My most complex PCB design to date — an ESP32-C3 based multi-sensor IoT board featuring three sensors across a hierarchical, multi-sheet schematic. Designed over multiple days following the Tech Explorations tutorial series. This was my first experience with both 4-layer PCB stackup design and microphone amplifier circuit design.
| Property | Details |
|---|---|
| MCU | ESP32-C3 |
| Board layers | 4-layer stackup |
| Schematic structure | Hierarchical — 3 separate sheets |
| Sensors | BME280, Electret Microphone + MAX4466EXK |
| EDA Tool | KiCad 9.0 |
| Design reference | Tech Explorations tutorial series |
| Status | Design complete |
| Layer | Function |
|---|---|
| Layer 1 (Top) | Signal + components |
| Layer 2 | Ground plane (GND) |
| Layer 3 | Power plane (VCC) |
| Layer 4 (Bottom) | Signal |
A dedicated ground plane on Layer 2 ensures low-impedance returns for all sensors and clean power distribution — critical for analog microphone signal integrity.
| Component | Part | Function | Interface |
|---|---|---|---|
| Environmental Sensor | BME280 (Bosch) | Temperature, humidity & pressure — 3-in-1 | I²C / SPI |
| Microphone | CMC-5042PF-AC (Same Sky) | 6mm omnidirectional electret condenser mic | Analog |
| Mic Amplifier | MAX4466EXK (Analog Devices) | Low-noise microphone amplifier, SC-70 package | Analog |
| MCU | ESP32-C3-02 | Wi-Fi + Bluetooth 5.0 LE microcontroller | — |
This design uses a hierarchical multi-sheet schematic — a professional approach for managing complex designs:
| Sheet | Contents |
|---|---|
Root page 1 |
Top-level hierarchy, power distribution, ESP32-C3 core |
sensors.kicad_sch |
BME280 environmental sensor + microphone + MAX4466 amplifier circuit |
user_interface.kicad_sch |
User-facing connections, GPIO breakouts, connectors |
| File | Description |
|---|---|
1st_ESP32_Demo_project.kicad_pro |
KiCad project file |
1st_ESP32_Demo_project.kicad_sch |
Root schematic |
ESP32-C3-02.kicad_sch |
ESP32-C3 sub-schematic sheet |
sensors.kicad_sch |
Sensors sub-schematic sheet |
user_interface.kicad_sch |
User interface sub-schematic sheet |
1st_ESP32_Demo_project.kicad_pcb |
PCB layout |
Footprints/ |
Custom footprint library |
- 4-layer PCB stackup design with dedicated ground and power planes
- Hierarchical multi-sheet schematic design in KiCad 9.0
- BME280 I²C sensor integration with proper decoupling
- Electret condenser microphone biasing and signal conditioning
- MAX4466EXK low-noise amplifier circuit design
- Analog signal routing considerations on a mixed-signal PCB
- ESP32-C3 peripheral assignment and RF antenna clearance
This design follows the Tech Explorations ESP32 PCB Design tutorial series.
Tech Explorations: https://www.youtube.com/@TechExplorations
Mymensingh Engineering College — EEE Department