MicroPython and Lua on the ESP32: programming without compiling

There is a way to program the ESP32 where you compile nothing: you flash a firmware, open a console and type Python. In five minutes you have an LED blinking. It is called MicroPython and it is the best on-ramp there is.

The other side: it is slower and not everything is covered. Let’s be honest about it.

What MicroPython is

It is a Python 3 implementation made for microcontrollers. It is small, fits on the ESP32 and gives you a REPL (interactive console) over USB or Wi-Fi.

Flash and connect

Install it with esptool (the firmware is published by micropython.org):

esptool.py --chip esp32 -p /dev/ttyUSB0 erase_flash
esptool.py --chip esp32 -p /dev/ttyUSB0 write_flash -z 0x1000 esp32-*.bin

And to talk to the board, mpremote:

mpremote connect /dev/ttyUSB0
>>> import machine, time
>>> led = machine.Pin(2, machine.Pin.OUT)
>>> while True:
...     led.value(not led.value()); time.sleep(1)

That is it. No compiling, no setup(), no loop(). Perfect for learning.

Upload your code

The ESP32 shows up as a file system (with boot.py and main.py):

mpremote cp main.py :main.py     # copy
mpremote run main.py             # run without copying

main.py runs automatically on boot.

The good

• Minimal curve if you know Python (or if you do not).
• Instant iteration: try a line and see the result.
• Great for teaching and for workshops.
• Good modules: machine, network, time, socket, json.

The bad (important)

1. Speed: it is interpreted, so forget fine timing or audio/video processing.
2. Memory: the interpreter takes part of the RAM; PSRAM helps, but it is not C.
3. Peripherals: not every ESP32 feature is exposed. If one is missing, you usually drop to C.
4. Real time: no real priority tasks like in FreeRTOS.
5. Production: for a serious product, you almost always end up in C/C++ or Rust.

And Lua (NodeMCU)?

It was popular with the ESP8266. Today it is largely parked: less support, fewer libraries, and MicroPython is nicer and more alive. For new projects, I do not recommend it.

Quick comparison

When to use it (and when not to)

Yes:

• You are learning or teaching.
• You want to try an idea in 10 minutes.
• The project is a sensor that publishes and does not need speed.

No:

• You need precise timing or DSP.
• You are going to production with memory or power constraints.
• You need a peripheral that is not exposed in Python.

Summary

• MicroPython: Python on the ESP32, no compiling, with a REPL and a file system. Current version: 1.29.
• It is the best way to start and to prototype fast.
• It is slower and uses more RAM: it does not fit everything.
• Lua/NodeMCU is no longer worth it for new projects.
• You can start in MicroPython and drop to C/Rust when the project demands it.

Next step: Rust on the ESP32, the other extreme: maximum safety and control. Or go back to the series hub.