How to Control LED Strips With Arduino – Part 3: Individually Addressable LEDs (WS2812B)

1#include <FastLED.h>
2#define NUM_LEDS 7
3#define DATA_PIN 13
4
5CRGB leds[NUM_LEDS];
6
7void setup() {
8  FastLED.addLeds<WS2812, DATA_PIN, GRB>(leds, NUM_LEDS);
9}
10
11void loop() {
12  for (int i = 0; i < NUM_LEDS; i++) {
13    leds[i] = CRGB(255, 0, 0);  // Red
14  }
15  FastLED.show();
16}

1#include <Adafruit_NeoPixel.h>
2#define NUM_LEDS 7
3#define DATA_PIN 13
4
5Adafruit_NeoPixel strip(NUM_LEDS, DATA_PIN, NEO_GRB + NEO_KHZ800);
6
7void setup() {
8  strip.begin();
9  strip.show();  // Initialize all pixels to 'off'
10}
11
12void loop() {
13  for (int i = 0; i < NUM_LEDS; i++) {
14    strip.setPixelColor(i, strip.Color(0, 255, 0));  // Green
15  }
16  strip.show();
17}

1#include <FastLED.h>
2
3#define LED_PIN     13
4#define NUM_LEDS    65
5#define BRIGHTNESS  200
6#define LED_TYPE    WS2812B
7#define COLOR_ORDER GRB
8
9CRGB leds[NUM_LEDS];
10
11uint8_t startColor = 0;
12const uint8_t colorStep = 3;
13unsigned long lastUpdate = 0;
14const unsigned long timeStep = 50;
15
16void setup() {
17  FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS);
18  FastLED.setBrightness(BRIGHTNESS);
19  fill_solid(leds, NUM_LEDS, CRGB::Black);
20}
21
22void loop() {
23  unsigned long currentTime = millis();
24  if (currentTime - lastUpdate >= timeStep) {
25    lastUpdate = currentTime;
26
27    // Shift all LEDs one step to the right
28    for (int i = NUM_LEDS - 1; i > 0; i--) {
29      leds[i] = leds[i - 1];
30    }
31
32    // Insert new hue at the front
33    leds[0] = CHSV(startColor, 255, 255);
34
35    // Advance to the next hue
36    startColor += colorStep;
37
38    FastLED.show();
39  }
40}

1#include <FastLED.h>
2
3#define NUM_LEDS 65
4#define DATA_PIN 13
5#define COLOR_COUNT 5
6#define FADE_STEP 0.5  // 50% of previous brightness
7
8CRGB leds[NUM_LEDS];
9
10CRGB colors[COLOR_COUNT] = {
11  CRGB::Red,
12  CRGB::Green,
13  CRGB::Blue,
14  CRGB::Magenta,
15  CRGB::Cyan
16};
17
18unsigned long lastStepTime = 0;
19unsigned long lastCometStart = 0;
20const int stepDelay = 60;       // ms between comet moves
21const int cometInterval = 2000;  // ms between new comets
22int cometCount = 0;
23
24struct Comet {
25  int position;
26  int colorIndex;
27  bool active;
28};
29
30#define MAX_COMETS 10
31Comet comets[MAX_COMETS];
32
33void setup() {
34  FastLED.addLeds<WS2812, DATA_PIN, GRB>(leds, NUM_LEDS);
35  FastLED.clear();
36}
37
38void loop() {
39  unsigned long currentTime = millis();
40
41  // Launch new comet
42  if (currentTime - lastCometStart >= cometInterval) {
43    // Start a new comet
44    for (int i = 0; i < MAX_COMETS; i++) {
45      if (!comets[i].active) {
46        comets[i] = {0, cometCount % COLOR_COUNT, true};
47        cometCount++;
48        lastCometStart = currentTime;
49        break;
50      }
51    }
52  }
53
54  // Step forward
55  if (currentTime - lastStepTime >= stepDelay) {
56    lastStepTime = currentTime;
57
58    // Fade all LEDs slightly
59    for (int i = 0; i < NUM_LEDS; i++) {
60      leds[i].nscale8(255 * FADE_STEP);  // dim by 10%
61    }
62
63    // Update comets
64    for (int i = 0; i < MAX_COMETS; i++) {
65      if (comets[i].active) {
66        if (comets[i].position < NUM_LEDS) {
67          leds[comets[i].position] = colors[comets[i].colorIndex];
68          comets[i].position++;
69        } else {
70          comets[i].active = false;
71        }
72      }
73    }
74
75    FastLED.show();
76  }
77}