How to use WS2812 RGB LEDs with Raspberry Pi Pico

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You will have to put your code in an infinite loop. Something like this will loop indefinitely. All this code is pretty similar to the tutorial. The only difference is the while True: loop at the bottom. I’ve removed some unused functions to make this example as small as possible while still functional.

# Example using PIO to drive a set of WS2812 LEDs forever

import array, time
from machine import Pin
import rp2

# Configure the number of WS2812 LEDs.
NUM_LEDS = 1
PIN_NUM = 22
brightness = 0.2

@rp2.asm_pio(sideset_init=rp2.PIO.OUT_LOW, out_shiftdir=rp2.PIO.SHIFT_LEFT, autopull=True, pull_thresh=24)
def ws2812():
    T1 = 2
    T2 = 5
    T3 = 3
    wrap_target()
    label("bitloop")
    out(x, 1)               .side(0)    [T3 - 1]
    jmp(not_x, "do_zero")   .side(1)    [T1 - 1]
    jmp("bitloop")          .side(1)    [T2 - 1]
    label("do_zero")
    nop()                   .side(0)    [T2 - 1]
    wrap()


# Create the StateMachine with the ws2812 program, outputting on pin
sm = rp2.StateMachine(0, ws2812, freq=8_000_000, sideset_base=Pin(PIN_NUM))

# Start the StateMachine, it will wait for data on its FIFO.
sm.active(1)

# Display a pattern on the LEDs via an array of LED RGB values.
ar = array.array("I", [0 for _ in range(NUM_LEDS)])

##########################################################################
def pixels_show():
    dimmer_ar = array.array("I", [0 for _ in range(NUM_LEDS)])
    for i,c in enumerate(ar):
        r = int(((c >> 8) & 0xFF) * brightness)
        g = int(((c >> 16) & 0xFF) * brightness)
        b = int((c & 0xFF) * brightness)
        dimmer_ar[i] = (g<<16) + (r<<8) + b
    sm.put(dimmer_ar, 8)
    time.sleep_ms(10)

def pixels_set(i, color):
    ar[i] = (color[1]<<16) + (color[0]<<8) + color[2]

while True:
    pixels_set(0, (255,0,0)) # Red
    pixels_show()
    time.sleep(1)
    pixels_set(0, (0,0,0)) # Off
    time.sleep(1)
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