ESP32-Sensing-Node

CUERT ESP32 sensing firmware, using C and the native ESP-IDF CMake build system. The starter logs a heartbeat once per second and does not configure sensor pins.

Hardware baseline

The reported board is an ESP32-S with 38 pins. This project assumes a classic ESP32 (usually an ESP32-WROOM-32 or ESP-32S module), not an ESP32-S2/S3/C3. Pin count alone does not identify the chip or flash capacity: check the metal module's marking. The initial flash configuration uses a conservative 2 MB, DIO, 40 MHz baseline. Change flash size in idf.py menuconfig after confirming the module's actual capacity; 38-pin boards often have 4 MB.

One-time Windows setup

1. Open this directory in VS Code.
2. Install the recommended Espressif ESP-IDF extension if missing.
3. Press Ctrl+Shift+P and run ESP-IDF: Open ESP-IDF Installation Manager.
4. Install a stable ESP-IDF version and its tools through the manager. Record the chosen version for the team so everyone uses the same release.
5. Run ESP-IDF: Select Current ESP-IDF Version and select that installation.
6. Run ESP-IDF: Doctor Command to verify the setup.
7. Open an ESP-IDF terminal using the extension's command palette.

ESP-IDF supplies the ESP32 cross-compiler, Python environment, CMake, Ninja, and esptool. Having desktop CMake alone is insufficient. Use the activated ESP-IDF environment for all commands below.

Build

On this PC, the EIM offline installer selected MSYS2 Python and failed to finish. The tools were retained and a native Windows Python 3.12 environment was repaired offline at C:\Espressif\tools\python\v6.1\venv-win. To activate it in a normal PowerShell terminal, run the following from this directory (the leading dot matters):

. .\Activate-ESP-IDF.ps1
idf.py --version
idf.py build

The activation script accepts installation paths as parameters for other PCs. The .vscode/settings.json ESP-IDF paths refer to this PC and must be adjusted for other installations. The manual setup works independently of EIM's completion screen or installation registry.

In an ESP-IDF terminal, from this project's root:

idf.py set-target esp32
idf.py build

Set the target once at initialization. Running set-target again regenerates configuration and clears the build directory. For later builds use only build. sdkconfig.defaults seeds a new configuration; subsequent changes belong in idf.py menuconfig and should be exported to defaults for the team when needed.

idf.py drives CMake and Ninja. To use CMake directly in the same environment:

cmake -S . -B build -G Ninja -DIDF_TARGET=esp32
cmake --build build

Outputs:

• build/esp32_sensing_node.elf: linked program and debug symbols.
• build/esp32_sensing_node.bin: application firmware.
• build/bootloader/bootloader.bin: second-stage bootloader.
• build/partition_table/partition-table.bin: flash partition layout.
• build/flasher_args.json: generated flash file locations and offsets.

ESP32 normally flashes binary .bin images rather than Intel HEX .hex. Use the generated flash information instead of guessing offsets.

Flash and monitor

Connect the board over USB with a data cable. Find its COM port in Windows Device Manager under Ports (COM & LPT), then replace COM5 below:

idf.py -p COM5 flash
idf.py -p COM5 monitor

Or build, flash, and monitor in one command:

idf.py -p COM5 flash monitor

flash also builds any pending changes. It uses esptool to communicate with the ESP32's built-in ROM download bootloader over USB-to-UART, and writes the bootloader, partition table, and application at their generated offsets. An ST-Link is not required for normal USB flashing.

Expected output is CUERT ESP32 sensing node started, then a heartbeat each second. Exit the monitor with Ctrl+]. VS Code also provides ESP-IDF commands for building, selecting a port, flashing using UART, and monitoring.

If no COM port appears, check the cable and the driver for the board's actual USB-to-UART chip (commonly CP210x or CH340). If flashing waits at Connecting, hold BOOT, tap EN/RESET, and release BOOT once flashing begins. Close other serial monitors before flashing. For an unreliable connection try idf.py -p COM5 -b 115200 flash.

GUI alternative

Espressif Flash Download Tools is the Windows GUI alternative to STM32 Utility. Choose ESP32 and load the .bin files at the offsets produced by your build. During development, the VS Code ESP-IDF extension or idf.py flash avoids manually entering the file paths and offsets.

References

• Windows ESP-IDF installation
• VS Code setup
• CMake build system
• Build and flash