PWM

boolean pushBtn1;
boolean pushBtn2;
#define ledPin 9
int brightness =128;
int delaytime=1000;
void setup()
{
  // put your setup code here, to run once:
 pinMode(2,INPUT_PULLUP);
 pinMode(3,INPUT_PULLUP);
 pinMode(ledPin,OUTPUT);
 Serial.begin(9600);
}

void loop()
{
  // put your main code here, to run repeatedly:
  pushBtn1=digitalRead(2);
  pushBtn2=digitalRead(3);
  if(!pushBtn1 && brightness >0)
  {
    brightness=brightness-5;
  }
  else if(!pushBtn1 && brightness <255)
  {
    brightness=brightness+5;
  }
  analogWrite(ledPin,brightness);
  Serial.println(brightness);
  delay(1000);
}