两个LED渐明渐灭代码

下面是两个LED渐明渐灭的代码，分别使用了PWM（脉冲宽度调制）的方式调节LED的亮度。

//引用Arduino内置库
#include <Arduino.h>

//定义LED引脚
#define LED1 3
#define LED2 5

//定义PWM信号的周期
#define PWM_PERIOD 2000

//定义渐变的速度
#define FADE_SPEED 10

int brightness1 = 0; //LED1当前亮度
int brightness2 = 0; //LED2当前亮度

void setup() {
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
}

void loop() {
  //LED1渐明
  for (int i = 0; i <= 255; i += FADE_SPEED) {
    brightness1 = i;
    analogWrite(LED1, map(brightness1, 0, 255, 0, PWM_PERIOD));
    delay(10);
  }

  //LED1渐暗
  for (int i = 255; i >= 0; i -= FADE_SPEED) {
    brightness1 = i;
    analogWrite(LED1, map(brightness1, 0, 255, 0, PWM_PERIOD));
    delay(10);
  }

  //LED2渐明
  for (int i = 0; i <= 255; i += FADE_SPEED) {
    brightness2 = i;
    analogWrite(LED2, map(brightness2, 0, 255, 0, PWM_PERIOD));
    delay(10);
  }

  //LED2渐暗
  for (int i = 255; i >= 0; i -= FADE_SPEED) {
    brightness2 = i;
    analogWrite(LED2, map(brightness2, 0, 255, 0, PWM_PERIOD));
    delay(10);
  }
}

该代码使用了Arduino的analogWrite函数，通过map函数将0到255的亮度值映射到一个PWM周期内，从而产生PWM信号。循环中的delay函数用于控制渐变速度，FADE_SPEED可以根据需要进行调整。