)nline Raspberry Pi Pico Simulator - NeoPixel LEDs! - 2022

Summary

In this project, you will learn how to connect Raspberry Pi Pico to a NexoPixel ring. from the supplier:

The rings are 'chainable' - connect the output pin of one to the input pin of another. Use only one microcontroller pin to control as many as you can chain together! Each LED is addressable as the driver chip is inside the LED. Each one has ~18mA constant current drive so the color will be very consistent even if the voltage varies, and no external choke resistors are required making the design slim. Power the whole thing with 5VDC and you're ready to rock.

Connection diagram

Code

# NeoPixels on the Pi Pico
# Sample code from http://www.pibits.net/code/raspberry-pi-pico-and-neopixel-example-in-micropython.php
import array, time
from machine import Pin
import rp2
# Configure the number of WS2812 LEDs, pins and brightness.
NUM_LEDS = 16
PIN_NUM = 7
brightness = 1
@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(16).
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]
def pixels_fill(color):
for i in range(len(ar)):
pixels_set(i, color)
BLACK = (0, 0, 0)
RED = (255, 0, 0)
YELLOW = (255, 150, 0)
GREEN = (0, 255, 0)
CYAN = (0, 255, 255)
BLUE = (0, 0, 255)
PURPLE = (180, 0, 255)
WHITE = (255, 255, 255)
COLORS = (BLACK, RED, YELLOW, GREEN, CYAN, BLUE, PURPLE, WHITE)
for color in COLORS:
pixels_fill(color)
pixels_show()
time.sleep(0.5)

More about Raspberry Pi Pico - Supporting Docs

https://docs.wokwi.com/parts/wokwi-pi-pico

Live project link

https://wokwi.com/arduino/projects/302135681537278473

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