int tasterGore = 5;
int tasterDolu = 10;
int nagore;
int nadolu;
int Led = 7;
int Svetlost = 0;
int pauza=250;
int zvucnik = 9;

void setup() {
  pinMode(Led, OUTPUT);
  pinMode(tasterGore, INPUT);
  pinMode(tasterDolu, INPUT);
  pinMode(zvucnik, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  nagore = digitalRead (tasterGore);
  nadolu = digitalRead (tasterDolu);
  Serial.print ("Svetlinata = ");
  Serial.println (Svetlost);
  delay (pauza);
  if (nagore == 0){
    Svetlost = Svetlost + 5;
  }
  if (nadolu == 0) {
    Svetlost = Svetlost - 5;
  }
  if (Svetlost > 255) {
    Svetlost = 255;
    digitalWrite (zvucnik, HIGH);
  }
  if (Svetlost < 0) {
    Svetlost = 0;
    digitalWrite (zvucnik, HIGH);
  }
  analogWrite (Led, Svetlost);
}