MicroPython notes

Pin out diagrams

Speciality hardware

Sensors and actuators

External LED or pin on/off 

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 to machine.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)

Neopixels

Using the MicroPython Neopixel library

from machine import Pin
import neopixel
import time

# Neopixel (Status LED)
pixel = neopixel.NeoPixel(Pin(48), 1)  # GPIO48, 1 Neopixel

while True:
    pixel[0] = (0,0,255) # Blue
    pixel.write()
    time.sleep(0.3)
    pixel[0] = (0,0,0) # Black
    pixel.write()
    time.sleep(0.3)

Other functionality

Connect to wifi

  • Requires stc.py Utility functions for STC projects (connect to wifi, get current time, send ntfy message)
import stc

# Provide the SSID and PASSWORD for your Wifi networks
# You may want to add your home wifi to this?
# For example: NETWORKS = [("SCWiFi","wifi1234"),("homewifi","password")]

NETWORKS = [("SCWiFi","wifi1234")]
ip = stc.connect_to_wifi(NETWORKS)
print(f"You are connected using IP address {ip}")

Get current date/time

  • Requires an active Internet connection over wifi (as per above)
import stc
import time

# Provide the SSID and PASSWORD for your Wifi networks
# You may want to add your home wifi to this?
# For example: NETWORKS = [("SCWiFi","wifi1234"),("homewifi","password")]

NETWORKS = [("SCWiFi","wifi1234")]
ip = stc.connect_to_wifi(NETWORKS)
print(f"You are connected using IP address {ip}")

# Get the current date/time from the internet
# Only needs to be executed once at startup
stc.set_correct_time(timezone_offset_hours=8) # Specify timezone difference from UTC

# Use this every time you want to fetch the time
year, month, mday, hour, minute, second, weekday, yearday = time.localtime()
print(f"Current time/date: {hour:02}:{minute:02}:{second:02} {year:04}-{month:02}-{mday:02}")

Send a message via ntfy 

import stc
NETWORKS = [("SCWiFi","wifi1234")]
ip = stc.connect_to_wifi(NETWORKS)
print(f"You are connected using IP address {ip}")

stc.send_nfty_message("your-channel", "This is your message")

Internet communication

Use the urequests library

import urequests

# 1. Download TEXT data from a GET HTTPS request
response = urequests.get("https://example.com/text")
text_data = response.text
response.close()
print("Text Data:", text_data)

# 2. Download JSON data from a GET HTTPS request, converted into a Dict
response = urequests.get("https://jsonplaceholder.typicode.com/todos/1")
json_data = response.json()
response.close()
print("JSON Data (GET):", json_data)

# 3. Download JSON data from a POST HTTPS request with header values sent, converted into a Dict
url = "https://jsonplaceholder.typicode.com/posts"
headers = {
    "Content-Type": "application/json",
    "Authorization": "Bearer YOUR_ACCESS_TOKEN"  # Replace with your token
}
payload = {
    "title": "foo",
    "body": "bar",
    "userId": 1
}
response = urequests.post(url, headers=headers, json=payload)
json_data = response.json()
response.close()
print("JSON Data (POST):", json_data)

Other resources

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Copyright © Paul Baumgarten.