第一条灯带保持呼吸灯状态，不要一点点变亮

好的，可以将代码修改为：

#include <FastLED.h>  

#define LED_PIN_1     3
#define LED_PIN_2     5
#define LED_COUNT_1   42
#define LED_COUNT_2   42
#define BRIGHTNESS  255
#define LED_TYPE    WS2812B
#define COLOR_ORDER GRB

CRGB leds_1[LED_COUNT_1];
CRGB leds_2[LED_COUNT_2];

void setup() {
  FastLED.addLeds<LED_TYPE, LED_PIN_1, COLOR_ORDER>(leds_1, LED_COUNT_1);
  FastLED.addLeds<LED_TYPE, LED_PIN_2, COLOR_ORDER>(leds_2, LED_COUNT_2);
  FastLED.setBrightness(BRIGHTNESS);
}

void loop() {
  int brightness_2 = 0;
  int fadeAmount = 5;

  for (int i = 0; i < 256; i++) {
    int brightness_1 = (exp(sin(i / 50.0 * PI)) - 0.36787944) * 108.0;
    for (int j = 0; j < LED_COUNT_1; j++) {
      leds_1[j].setRGB(brightness_1, brightness_1, brightness_1);
    }
    FastLED.show();
    delay(25);
  }

  while (brightness_2 <= 255) {
    for (int i = 0; i < LED_COUNT_2; i++) {
      leds_2[i].setRGB(255, 255, 0);
      leds_2[i].fadeLightBy(brightness_2);
    }
    FastLED.show();
    brightness_2 += fadeAmount;
    delay(25);
  }

  while (brightness_2 >= 0) {
    for (int i = 0; i < LED_COUNT_2; i++) {
      leds_2[i].setRGB(255, 255, 0);
      leds_2[i].fadeLightBy(brightness_2);
    }
    FastLED.show();
    brightness_2 -= fadeAmount;
    delay(25);
  }
}

这个代码会让第一条灯带保持呼吸灯的状态，然后第二条灯带从灭的状态开始，一点一点变成黄色并且变亮，最后第二条灯带再一点一点变暗。你可以调整 `delay()` 函数的参数来改变呼吸灯的速度。