ESP 32-C3 Super Mini and MicroPython

Thanks to:

Random Nerd Tutorials : https://RandomNerdTutorials.com/raspberry-pi-pico-web-server-micropython/
FritzenLab electronics: https://fritzenlab.net/2025/03/15/configuring-micropython-on-esp32-c3-super-mini/

Photo - larger than actual size

Pinout

Specs:

C3

Because someone will ask.

Processor: Espressif ESP32-C3, 32-bit RISC-V single-core, up to 160 MHz

ROM: 384 KB

SRAM: 400 KB

Flash Memory: 4MB onboard SPI flash

Wi-Fi: 802.11 b/g/n (2.4 GHz)

Bluetooth: Bluetooth 5.0 (BLE)

Form Factor: ~22.5 x 18 mm

Pi Pico

Processor: Raspberry Pi RP2040 32-bit Arm Cortex-M0+ dual-core, up to 133 MHz

SRAM: 264KB

Flash Memory: 2MB onboard QSPI flash.

Wi-Fi Seperate module.

Installing Python

Download the micropython interpreter for the C3 from:

https://micropython.org/download/ESP32_GENERIC_C3/

I picked the most recent version.

Using the command line:

I created a python virtual environment and installed esptool:

cd ~
mkdir esp32v
python3 -m venv esp32v
source env32v/bin/activate
cd esp32v
pip install esptool

Connect the ESP32-C3 super mini to a USB port.

On my Ubuntu it connected to /dev/ttyACM0

Then erase the existing flash and load python:

esptool.py --port /dev/ttyACM0 erase_flash
esptool.py --port /dev/ttyACM0 --baud 460800 write_flash 0 ESP32_GENERIC_C3-20250911-v1.26.1.bin

I then ran Thonny to talk to the ESP32, and it did.

A flashing led

import machine
import time

# The ESP32 supermini onboard led is on pin 8
led= machine.Pin(8, machine.Pin.OUT)

while True:
    led.value(not led.value())
    time.sleep(1)

and we are done...

Except ...

Why not have a web server that turns the led on and off and displays the temperature, and gives you a random number because Rui thought it would be a fine idea.

DS18B20 Wiring. Note 4.7 K Pull Up Resistor

ESP 32-C3 Web Server Code

Notes:

Thonny does not seem to do a hard reset on the ESP32-C3 board and it leaves network connections in an undefined state when you reload the program and try to bring up the network. The solution is to click the Reset button.

Comments from the Jitsi Chat

KB UVic Amateur radio exam:
https://docs.google.com/forms/d/e/1FAIpQLSfe0UzpYWGpClA2v-Y4rtIZkZMyZDrTPAYe0mLmD3-NqNkyYw/viewform
DH Tip for increasing the WiFi Range of the ESP32-C3:
https://peterneufeld.wordpress.com/2025/03/04/esp32-c3-supermini-antenna-modification/
DH Information on the Python random() method:
https://docs.micropython.org/en/latest/library/random.html
DH If you want a more sophisticated webserver, a nice one is called microdot:
https://microdot.readthedocs.io/en/latest/