ESP32-IoT

ESP32-IoT PCB

An ESP32-C3 based IoT controller board designed in KiCad. The board combines wireless control, sensor interfaces, local storage, audio/light sensing, USB connectivity, and single-cell Li-ion battery support on a compact four-layer PCB.

Main features

• ESP32-C3-WROOM-02-H4 wireless microcontroller module
• BME280 environmental sensor
• MicroSD card interface
• W25Q32JV external SPI flash
• MAX4466 microphone amplifier and CMC-5042PF-AC microphone
• TEMT6000X01 ambient light sensor
• USB-C connector with:
  • CP2102N USB-to-UART bridge
  • USB ESD protection
  • Boot and reset controls
• Single-cell Li-ion power path:
  • MCP73871 charger/power-path controller
  • JST battery connector
  • 3.3 V LM1117 regulator
• Status and activity LEDs
• Exposed SPI test points for SCLK, MOSI, MISO, chip select, and SD chip select
• Two M2 mounting holes

PCB specifications

The board outline includes a stepped/notched section around the USB connector edge. Use the Edge.Cuts layer in the KiCad board file, rather than the approximate dimensions above, for fabrication.

Repository layout

Design files

• ESP32-IoT.kicad_pcb — PCB layout
• ESP32-IoT.kicad_sch — main schematic
• esp32-c3-02.kicad_sch — ESP32-C3 subsystem
• sensors.kicad_sch — sensor subsystem
• user-interface.kicad_sch — user-interface subsystem
• ESP32-IoT.kicad_pro — KiCad project

Libraries and reference material

• Libraries/Footprints/ — project-specific footprints
• Libraries/Symbols/ — project-specific symbols
• Libraries/3D models/ — STEP models used by the board
• Datasheets/ — component datasheets
• fp-lib-table and sym-lib-table — project library configuration

Opening the design

1. Install KiCad with PCB Editor and Schematic Editor.
2. Clone or download this repository while preserving the directory layout.
3. Open ESP32-IoT.kicad_pro.
4. Open the schematic and PCB from the KiCad project manager.
5. Keep the project-local Libraries directory beside the project files so the paths in fp-lib-table and sym-lib-table resolve correctly.

The PCB was saved by KiCad 10.0. Older KiCad releases may not be able to open the board without conversion. Save a copy before converting the project.

Assembly and bring-up notes

Populate and inspect the power section before fitting the ESP32-C3 module. Check for shorts between +3.3V, USB VBUS, battery input, and GND, then verify the regulator output with a current-limited supply.

For first power-up:

1. Leave the battery disconnected and power the board from USB.
2. Verify the 3.3 V rail and the power/status LED.
3. Confirm that the CP2102N enumerates over USB.
4. Use the BOOT and RESET switches to enter the ESP32-C3 download mode.
5. Program and test the ESP32-C3 firmware before connecting a battery.

Observe the polarity markings for the battery connector and polarized capacitors. Do not connect a Li-ion cell until the charger and power-path voltages have been verified.

Design status

This repository contains the KiCad source and exported fabrication files. Firmware, a complete assembly BOM, and a documented connector pinout are not included in the current project snapshot. Validate the latest schematic, component values, ERC/DRC results, and manufacturer capabilities before production.

License

This project is licensed under the MIT License.

The MIT license allows reuse, modification, distribution, and commercial use, provided that the copyright notice and permission notice are retained in all copies or substantial portions of the project.