MicroPython
A collection of sample code extracts for commonly used tasks within MicroPython when used on a microprocessor such as the RP2040 (Raspberry Pi Pico), ESP32, or Microbit.
Raspberry Pi Pico pinout diagram
My current recommended IDE for MicroPython is Thonny. It has excellent hardware support for the commonly used devices. Check this connection guide for the Raspberry Pi Pico.
Operate an LED or simple device
import machine, time
# Using GP28
led = machine.Pin(28, machine.Pin.OUT)
while True:
print("blink!")
led.on()
time.sleep(0.2)
led.off()
time.sleep(0.2)
To use the on-board LED of the Pico W,
led = machine.Pin("LED", machine.Pin.OUT)
Detect button press
import machine, time
led = machine.Pin(28, machine.Pin.OUT)
# Using GP27 and 3.3V for button
button = machine.Pin(27, machine.Pin.IN, machine.Pin.PULL_DOWN)
print("Waiting...")
while True:
if button.value():
print("Button pressed")
led.on()
time.sleep(1)
led.off()
time.sleep(0.2)
- Note: If you are connecting the button between a GPxx pin and ground, you will need to invert your button.value() check… ie
if not button.value():and set the pin built-in resistor tomachine.Pin.PULL_UP.
import machine, time
led = machine.Pin("LED", machine.Pin.OUT)
# Using GP27 and GND for button
button = machine.Pin(27, machine.Pin.IN, machine.Pin.PULL_UP)
print("Waiting...")
while True:
if not button.value():
print("Button pressed")
led.on()
time.sleep(1)
led.off()
time.sleep(0.2)
9g servo
Download the Servo library file and save it to your board as servo.py.
import time
from machine import Pin,PWM
from servo import Servo
sg90_servo = Servo(pin=0) # Update for correct GPxx pin number
button = machine.Pin(2, machine.Pin.IN, Pin.PULL_UP) # Pin 2 and GND
while True:
if not button.value(): # If button pressed
print("Button press detected")
# Servo operation
sg90_servo.move(35) # turns the servo to 0°.
time.sleep(0.9)
sg90_servo.move(90) # turns the servo to 90°.
time.sleep(1)
time.sleep(0.2)
- You will need to experiment with the values supplied to
.move()as it varies from device to device.
Neopixels
Download the Neopixel library file and save it to your board as neopixel.py.
Rotating pattern across 8 LEDs
import time
from neopixel import Neopixel
# Number of LEDs, state library (use 0), GPIO pin, color scheme of LEDs
pixels = Neopixel(8, 0, 28, "GRB")
colors = [
(255, 0, 0), # Red
(255, 127, 0), # Orange
(255, 255, 0), # Yellow
(0, 255, 0), # Green
(0, 0, 255), # Blue
(127, 0, 255), # Violet
(255, 0, 127), # Pink
(255, 255, 255) # White
]
while True:
pixels.clear()
# Set each LED to a color
for i in range(len(colors)):
print(f"Setting LED {i} to {colors[i]}")
pixels[i] = colors[i]
pixels.show()
time.sleep(0.2)
time.sleep(1)
# Set each LED to off
for i in range(len(colors)):
print(f"Setting LED {i} to off")
pixels[i] = (0,0,0)
pixels.show()
time.sleep(0.2)
time.sleep(1)
Connect to WiFi
import network
import machine
import time
def connect_to_wifi(networks):
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
print(networks)
for ssid, password in networks:
print(f"Trying to connect to: {ssid}")
wlan.connect(ssid, password)
# Wait for connection or timeout
for i in range(10):
if wlan.isconnected():
print(f"✅ Connected to {ssid}")
print(f"IP address: {wlan.ifconfig()[0]}")
return wlan.ifconfig()[0]
time.sleep(0.5)
print(f"❌ Failed to connect to {ssid}\n")
# Disconnect before trying the next one
wlan.disconnect()
time.sleep(1)
print("🚫 Could not connect to any known Wi-Fi networks.")
return None
NETWORKS = [("SSID", "PASSWORD")]
ip = connect_to_wifi(NETWORKS)
Obtain the current time
import time
import machine
import ntptime
# NTP Time Fetching Function
# Assumes WiFi connected device
def set_correct_time(timezone_offset_hours=8):
while True:
try:
ntptime.settime()
break
except:
print("Fetching the current time/date...")
time.sleep(5)
# Update for timezone
local_time = time.localtime(time.time() + timezone_offset_hours*(60*60))
# Extract local time from the tuple provided by time.localtime()
year, month, mday, hour, minute, second, weekday, yearday = local_time
rtc_weekday = (weekday + 1) % 7 # RTC uses Sunday as 0
# Update the real time clock to local time
rtc = machine.RTC()
rtc.datetime((year, month, mday, rtc_weekday, hour, minute, second, 0))
print(f"Current time/date: {hour:02}:{minute:02}:{second:02} {year:04}-{month:02}-{mday:02}")
set_correct_time()
Request data via HTTP/S
ntfy.sh is a handy little service for obtaining notifications to your mobile device from code. I find it very useful for having MicroProcessor projects use it to advise me of their IP address so I can interact with them.
import json
import machine
import urequests
def send_nfty_message(channel, message, link=None, server="https://ntfy.sh/"):
print(f"[sending ntfy message] {server+channel} '{message}'")
if link:
response = urequests.post(url=server+channel, data=message, headers=[{"action":"view", "label":"Open", "url": link}])
else:
response = urequests.post(url=server+channel, data=message)
res = response.text
print(f"[ntfy reply]",response.status_code,res)
response.close()
return res
message = "My IoT device is at @ http://"+ip
send_nfty_message("your-ntfy-channel", message)
Simple web-server
I’ve written a simple web-server for the use of STC students. Download it and save as webserver.py.
There is also an associated stc library to contain commonly needed functions that it uses. Download the stc library and save as stc.py.
import network
import usocket as socket
from machine import Pin
import time
import json
import machine
import ntptime
import webserver # webserver.py
import stc # stc.py
# Constants
NETWORKS = [("SSID","PASSWORD")] # Adjust as required
LED_PIN = 0 # Adjust as required
# Instantiate the LED pin
led = Pin(LED_PIN, Pin.OUT)
def callback(request):
print("Received request",request)
if request == "on":
led.on()
if request == "off":
led.off()
return
# Main function
def main():
ip = webserver.connect_to_wifi(NETWORKS)
stc.set_correct_time()
stc.send_nfty_message("your-ntfy-channel", "My IoT lamp @ http://"+ip)
webserver.start_server("0.0.0.0", 80, "index.html", callback)
# Run the program
if __name__ == '__main__':
main()
CYD Demo code
For the CYD (Cheap Yellow Device)
import machine
#from machine import Pin, SPI, ADC, idle, RTC
import os
import time
import stc
import random
from ili9341 import Display, color565
from xpt2046 import Touch
from xglcd_font import XglcdFont
WIFI = [("SCWiFi", "wifi1234")]
X,Y = 0,0 # Globals to contain coordinates of last touch
def touchscreen_press(x, y):
global X,Y
print(f"Touch at x={x}, y={y}")
X,Y = x,y
### SETUP HARDWARE
spi_1 = machine.SPI(1, baudrate=10000000, sck=machine.Pin(14), mosi=machine.Pin(13), miso=machine.Pin(12))
display = Display(spi_1, dc=machine.Pin(2), cs=machine.Pin(15), rst=machine.Pin(15), width=320, height=240, rotation=0)
touchscreen = Touch(spi_1, cs=machine.Pin(33), int_pin=machine.Pin(36), int_handler=touchscreen_press, width=320, height=240)
backlight = machine.Pin(27, machine.Pin.OUT)
backlight.on()
unispace_font = XglcdFont('fonts/Unispace12x24.c', 12, 24)
# Color codes are BGR
white_color = color565(255, 255, 255)
black_color = color565(0, 0, 0)
red_color = color565(0, 0, 255)
yellow_color = color565(0, 255, 255)
green_color = color565(0, 255, 0)
# Main
if __name__=="__main__":
display.clear(black_color)
display.draw_text(0, 0, 'Connecting to wifi...', unispace_font, white_color, black_color)
stc.connect_to_wifi(WIFI)
display.clear(black_color)
display.draw_text(0, 0, 'Fetching time...', unispace_font, white_color, black_color)
stc.set_correct_time()
(year, month, mday, hour, minute, second, weekday, yearday) = time.localtime()
display.draw_text(0, 0, f'{mday:02}/{month:02}/{year:02}, {hour:02}:{minute:02}:{second:02}', unispace_font, white_color, black_color)
display.draw_text(0, 25, f'Use touchscreen...', unispace_font, white_color, black_color)
while True: # Play forever
x,y=X,Y
(year, month, mday, hour, minute, second, weekday, yearday) = time.localtime()
display.draw_text(0, 0, f'{mday:02}/{month:02}/{year:02}, {hour:02}:{minute:02}:{second:02} ', unispace_font, white_color, black_color)
display.draw_text(0, 25, f'x={x},y={y} ', unispace_font, white_color, black_color)
display.fill_circle(x, y, 10, white_color)
time.sleep(0.1)
display.fill_circle(x, y, 10, black_color)