MicroPython basics

Learn

What you’ll learn

• What MicroPython is and which boards run it
• Python syntax compared with Arduino C++
• Controlling pins, reading inputs and timing

MicroPython

MicroPython is a small version of Python that runs directly on microcontrollers such as the Raspberry Pi Pico, ESP32 and BBC micro:bit. You type code, save it as main.py on the board, and it runs.

Python vs Arduino C++

Arduino C++	MicroPython
int x = 5;	x = 5
{ } blocks	indentation (4 spaces)
; at line ends	no semicolons
if (x > 3) { ... }	if x > 3:
for (int i = 0; i < 5; i++)	for i in range(5):
delay(500)	time.sleep(0.5)
void loop()	while True:

Pins

from machine import Pin, ADC
import time

led = Pin(25, Pin.OUT)            # output
button = Pin(14, Pin.IN, Pin.PULL_UP)
knob = ADC(26)                    # analog input on the Pico

while True:
    if button.value() == 0:       # pressed (pulled up)
        led.on()
    else:
        led.off()
    print(knob.read_u16())        # 0–65535
    time.sleep(0.1)

Note

On a Pico W, the on-board LED is Pin("LED", Pin.OUT) instead of pin 25.

Examples

Example: a PWM fade on the Pico

from machine import Pin, PWM
import time

led = PWM(Pin(25))
led.freq(1000)
while True:
    for duty in range(0, 65536, 1024):
        led.duty_u16(duty)
        time.sleep(0.01)

Example: the same blink in both languages

// Arduino C++
void loop() {
  digitalWrite(13, HIGH); delay(500);
  digitalWrite(13, LOW);  delay(500);
}

# MicroPython
while True:
    led.toggle()
    time.sleep(0.5)

Practice

Try it in a virtual Raspberry Pi Pico

Press Start simulator, paste this into main.py, and press ▶. The LED on the Pico blinks and the console prints a count.

main.py

from machine import Pin
import time

led = Pin(25, Pin.OUT)   # the Pico's on-board LED

for i in range(10):
    led.toggle()
    print("blink", i)
    time.sleep(0.5)

Virtual Raspberry Pi Pico (MicroPython)Open full screen ↗

Start simulator

Runs on Wokwi, free, no account needed.

Forever blinkEasy

Change the program to blink forever, twice per second.

Show an answer

while True:
    led.toggle()
    time.sleep(0.25)

CountdownMedium

Print 10 down to 1, one per second, then “Go!”.

Show an answer

for n in range(10, 0, -1):
    print(n)
    time.sleep(1)
print("Go!")

Translate itHard

Translate the Arduino “count button presses” example (Arduino C++ basics lesson, Examples tab) into MicroPython.

Show an answer

from machine import Pin
import time

button = Pin(14, Pin.IN, Pin.PULL_UP)
presses = 0
was = False
while True:
    pressed = button.value() == 0
    if pressed and not was:
        presses += 1
        print("Presses:", presses)
        time.sleep(0.05)
    was = pressed

Quick check

1. How does Python mark a block of code?

Curly bracesIndentationSemicolonsBrackets

2. What is the MicroPython version of delay(500)?

time.sleep(500)time.sleep(0.5)wait(0.5)pause(500)

3. What replaces Arduino’s loop() in MicroPython?

while True:for ever:def loop:repeat:

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