int bright=0;
int fade=5;
void setup() {
  // put your setup code here, to run once:
pinMode(A1, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
analogWrite(A1, bright);
  bright += fade;
if (bright<=0 || bright>=255){
  fade = -fade;
}
delay(50);
}