New to Python and Raspberry pi's

Question

So i have started to play with the pi pico w and using them to light up some of my lego sets. this is the first time doing this, so i'm very new to coding in Python. i have all a total of 11 lights i would like to light up, and then randomly dim one off and then back on while it is on. the lights are connected to pins 21,22,24,25,26,27,29,30,31,32,34. i have been looking online to see how i can randomize within the array of pins, but i have not been able to find what i'm looking for. i have found this bit of code from the website Random Nerds Tutorial:

# Complete project details at https://RandomNerdTutorials.com/raspberry-pi-pico-pwm-micropython/
from machine import Pin, PWM
from time import sleep

# Set up PWM Pin
led = machine.Pin(20)
led_pwm = PWM(led)
duty_step = 129  # Step size for changing the duty cycle

#Set PWM frequency
frequency = 5000
led_pwm.freq (frequency)

try:
    while True:
      # Increase the duty cycle gradually
      for duty_cycle in range(0, 65536, duty_step):
        led_pwm.duty_u16(duty_cycle)
        sleep(0.005)
        
      # Decrease the duty cycle gradually
      for duty_cycle in range(65536, 0, -duty_step):
        led_pwm.duty_u16(duty_cycle)
        sleep(0.005)

i figure if i can get all the pins on at first, then switch the Increase and Decrease that would dim a light randomly. but then to run this on a random pin within a range of pins i have no idea. any help would be great

Answer 1

You can modify your code like this:

from machine import Pin, PWM
from time import sleep
import random

# Define the pins connected to your lights
pins = [21, 22, 24, 25, 26, 27, 29, 30, 31, 32, 34]

# Set up PWM Pin
def setup_pwm(pin):
    led = Pin(pin, Pin.OUT)
    led_pwm = PWM(led)
    frequency = 5000
    led_pwm.freq(frequency)
    return led_pwm

# Function to randomly select a pin and dim it
def random_dim():
    random_pin = random.choice(pins)
    led_pwm = setup_pwm(random_pin)
    duty_step = 129  # Step size for changing the duty cycle
    try:
        while True:
            # Increase the duty cycle gradually
            for duty_cycle in range(0, 65536, duty_step):
                led_pwm.duty_u16(duty_cycle)
                sleep(0.005)

            # Decrease the duty cycle gradually
            for duty_cycle in range(65536, 0, -duty_step):
                led_pwm.duty_u16(duty_cycle)
                sleep(0.005)
    finally:
        led_pwm.deinit()  # Cleanup PWM after use

# Run the random_dim function
random_dim()

If you need some more detail info about Implementing PWM with Raspberry Pi Pico using MicroPython, you can see this article:

https://www.theengineeringprojects.com/2022/05/implementing-pwm-with-raspberry-pi-pico-using-micropython.html

Answer 2

Put your pins in a list (Pin 20 is PWM). Use a for statement to set the pins in an array. In your main loop random select pin from the list with random.randrange. See: https://docs.micropython.org/en/latest/rp2/quickref.html# and https://docs.micropython.org/en/latest/library/random.html

# Example:
import random
from machine import Pin, PWM
from time import sleep

a = []  # Array        V changed from 20 (PWM pin)
mlst = [15,16,17,18,19,14,21,22,26,27,28]
for x in mlst:
    p = Pin (x, Pin.OUT, value=1)
    a.append(p)
    #print(p)

# Main Loop
for x in range(10):
    y = random.randrange(len(mlst))
    print(mlst[y], "--", a[y], "--", a[y].value())
    if a[y].value() == 1: a[y].value(0)
    else: a[y].value(1)

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