#include <FastLED.h> #define LED_PIN 3 #define LED_COUNT 42 #define BRIGHTNESS 255 #define LED_TYPE WS2812B #define COLOR_ORDER GRB CRGB leds[LED_COUNT]; void setup() { FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, LED_COUNT); FastLED.setBrightness(BRIGHTNESS); } void loop() { int brightness = 0; int fadeAmount = 5; while (brightness <= 255) { for (int i = 0; i < LED_COUNT; i++) { leds[i].setRGB(brightness, brightness, brightness); } FastLED.show(); brightness += fadeAmount; delay(25); } while (brightness >= 0) { for (int i = 0; i < LED_COUNT; i++) { leds[i].setRGB(brightness, brightness, brightness); } FastLED.show(); brightness -= fadeAmount; delay(25); } }颜色改为绿色

要将上述代码中的颜色改为绿色，只需要将 `leds[i].setRGB(brightness, brightness, brightness);` 中的三个参数改为 `0, brightness, 0`，这将会使 LED 显示出绿色。改完后的代码如下：

#include <FastLED.h>  

#define LED_PIN     3
#define LED_COUNT   42
#define BRIGHTNESS  255
#define LED_TYPE    WS2812B
#define COLOR_ORDER GRB

CRGB leds[LED_COUNT];  

void setup() {
  FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, LED_COUNT);
  FastLED.setBrightness(BRIGHTNESS);
}

void loop() {
  int brightness = 0;
  int fadeAmount = 5;      

  while (brightness <= 255) {
    for (int i = 0; i < LED_COUNT; i++) {
      leds[i].setRGB(0, brightness, 0);
    }
    FastLED.show();
    brightness += fadeAmount;
    delay(25);
  }      

  while (brightness >= 0) {
    for (int i = 0; i < LED_COUNT; i++) {
      leds[i].setRGB(0, brightness, 0);
    }
    FastLED.show();
    brightness -= fadeAmount;
    delay(25);
  }
}

请注意，这只是将 LED 的颜色改为了绿色，并没有改变代码的其他功能。