MicroPython Programming with ESP32 and ESP8266 (1)

Introduction

MicroPython is a lightweight implementation of Python designed for microcontrollers. It provides an interactive prompt (REPL) and supports most Python libraries, making it ideal for IoT applications. The ESP32 and ESP8266 microcontrollers are widely used due to their Wi-Fi capabilities and compatibility with MicroPython.

In this guide, we will cover:

• Installing MicroPython on ESP32 and ESP8266.
• Writing and running basic MicroPython programs.
• Using sensors and GPIO control with MicroPython.

Prerequisites

Before proceeding, ensure you have:

• An ESP32 or ESP8266 board.
• A USB cable to connect the board to your computer.
• Python 3.7+ installed on your system.
• Thonny or uPyCraft IDE for writing and uploading MicroPython code.

Step 1: Flashing MicroPython Firmware

To use MicroPython on your ESP32/ESP8266, you need to flash the firmware.

1. Download MicroPython Firmware

Download the latest firmware for your board from the official MicroPython website:

• ESP32: https://micropython.org/download/esp32/
• ESP8266: https://micropython.org/download/esp8266/

2. Install esptool

Install esptool, a command-line utility for flashing firmware:

pip install esptool

3. Erase Flash Memory

Before flashing, erase the existing firmware:

esptool.py --port /dev/ttyUSB0 erase_flash

(Replace /dev/ttyUSB0 with the correct port, e.g., COM3 on Windows.)

4. Flash MicroPython

Flash the downloaded MicroPython firmware:

esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0x1000 firmware.bin

After flashing, restart the board.

Step 2: Connecting to the MicroPython REPL

The REPL (Read-Eval-Print Loop) allows you to interact with MicroPython.

1. Connect via Serial Terminal

Use a serial terminal like screen or picocom (Linux/macOS):

screen /dev/ttyUSB0 115200

Or use Thonny IDE (recommended for beginners) by selecting the MicroPython interpreter.

Step 3: Writing and Uploading MicroPython Code

1. Blink an LED

Create a Python script blink.py:

from machine import Pin
import time

led = Pin(2, Pin.OUT)  # GPIO2 is the onboard LED

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

Upload and run it using Thonny or ampy:

ampy --port /dev/ttyUSB0 put blink.py

2. Read a Sensor (DHT11 Temperature & Humidity Sensor)

Connect a DHT11 sensor to GPIO4 and use this script:

import dht
import machine

sensor = dht.DHT11(machine.Pin(4))

sensor.measure()
print("Temperature:", sensor.temperature(), "C")
print("Humidity:", sensor.humidity(), "%")

Step 4: Using Wi-Fi on ESP32/ESP8266

Connect to a Wi-Fi network using MicroPython:

import network

sta = network.WLAN(network.STA_IF)
sta.active(True)
sta.connect("Your_SSID", "Your_PASSWORD")

while not sta.isconnected():
    pass

print("Connected!", sta.ifconfig())

Conclusion

You have successfully set up MicroPython on ESP32/ESP8266 and learned how to:

• Flash the firmware.
• Use the REPL terminal.
• Control GPIOs and read sensor data.
• Connect to Wi-Fi.

Now, you can start building IoT applications with MicroPython!