Documentation

// WS2812B Strip - Arduino with FastLED
// Install: FastLED library via Arduino Library Manager
// DIN on Digital Pin 6, 30 LEDs (cut from a longer strip)

#include <FastLED.h>

#define DATA_PIN  6
#define NUM_LEDS  30
#define BRIGHTNESS 64    // 0 - 255 (lower = less current draw)

CRGB leds[NUM_LEDS];

void setup() {
  FastLED.addLeds<WS2812B, DATA_PIN, GRB>(leds, NUM_LEDS);
  FastLED.setBrightness(BRIGHTNESS);
}

void loop() {
  // Rainbow chase
  static uint8_t hue = 0;
  for (int i = 0; i < NUM_LEDS; i++) {
    leds[i] = CHSV(hue + (i * 8), 255, 255);
  }
  FastLED.show();
  hue++;
  delay(20);
}

// WS2812B Strip - ESP32 with FastLED (RMT-driven)
// DIN on GPIO 5, 60 LEDs

#include <FastLED.h>

#define DATA_PIN  5
#define NUM_LEDS  60
#define BRIGHTNESS 64

CRGB leds[NUM_LEDS];

void setup() {
  Serial.begin(115200);
  FastLED.addLeds<WS2812B, DATA_PIN, GRB>(leds, NUM_LEDS);
  FastLED.setBrightness(BRIGHTNESS);
}

void loop() {
  // Sinelon: a single moving pixel with fading trail
  fadeToBlackBy(leds, NUM_LEDS, 20);
  int pos = beatsin16(13, 0, NUM_LEDS - 1);
  leds[pos] += CHSV(millis() / 10, 200, 255);
  FastLED.show();
  delay(15);
}

#!/usr/bin/env python3
# WS2812B Strip - Raspberry Pi Example
# sudo pip install rpi_ws281x
# Run as root (sudo) because PWM access requires root.

import time
from rpi_ws281x import PixelStrip, Color

LED_COUNT      = 30
LED_PIN        = 18       # GPIO 18 (Pin 12, PWM0)
LED_FREQ_HZ    = 800000
LED_DMA        = 10
LED_BRIGHTNESS = 64        # 0 - 255
LED_INVERT     = False
LED_CHANNEL    = 0

strip = PixelStrip(LED_COUNT, LED_PIN, LED_FREQ_HZ, LED_DMA,
                   LED_INVERT, LED_BRIGHTNESS, LED_CHANNEL)
strip.begin()

def wheel(pos):
    if pos < 85:
        return Color(pos * 3, 255 - pos * 3, 0)
    elif pos < 170:
        pos -= 85
        return Color(255 - pos * 3, 0, pos * 3)
    else:
        pos -= 170
        return Color(0, pos * 3, 255 - pos * 3)

try:
    j = 0
    while True:
        for i in range(LED_COUNT):
            strip.setPixelColor(i, wheel((i * 256 // LED_COUNT + j) & 255))
        strip.show()
        j = (j + 1) % 256
        time.sleep(0.02)
except KeyboardInterrupt:
    for i in range(LED_COUNT):
        strip.setPixelColor(i, Color(0, 0, 0))
    strip.show()

# WS2812B Strip - Pico MicroPython with PIO
# DIN on GP0, 30 LEDs

import array
import time
from machine import Pin
import rp2

NUM_LEDS = 30
PIN_NUM  = 0

@rp2.asm_pio(sideset_init=rp2.PIO.OUT_LOW, out_shiftdir=rp2.PIO.SHIFT_LEFT,
             autopull=True, pull_thresh=24)
def ws2812():
    T1, T2, T3 = 2, 5, 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()

sm = rp2.StateMachine(0, ws2812, freq=8_000_000, sideset_base=Pin(PIN_NUM))
sm.active(1)

ar = array.array("I", [0] * NUM_LEDS)

def show():
    for i in range(NUM_LEDS):
        sm.put(ar[i], 8)

def set_pixel(i, r, g, b):
    ar[i] = (g << 16) | (r << 8) | b   # GRB order

# Rainbow loop
hue = 0
while True:
    for i in range(NUM_LEDS):
        h = (hue + i * 8) % 360
        # naive HSV to RGB
        r = int(255 * max(0, min(1, abs((h/60) % 6 - 3) - 1)))
        g = int(255 * max(0, min(1, abs((h/60 + 4) % 6 - 3) - 1)))
        b = int(255 * max(0, min(1, abs((h/60 + 2) % 6 - 3) - 1)))
        set_pixel(i, r // 4, g // 4, b // 4)
    show()
    hue = (hue + 5) % 360
    time.sleep_ms(30)