控制LED的亮度

int i=6;
void setup() {
  // put your setup code here, to run once:
  pinMode(i,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  analogWrite(i,0);
  delay(1000);
  analogWrite(i,50);
  delay(1000);
  analogWrite(i,100);
  delay(1000);
  analogWrite(i,150);
  delay(1000);
  analogWrite(i,200);
  delay(1000);
  analogWrite(i,250);
  delay(1000);
}

这里用到了analogWrite，参数一是引脚值，参数二是输出的电压值，最大是255V。这里有一个前提，输出的引脚只能是带波浪线的数字引脚，这样才能改变电压值