leddimmer.ino

int leds = 9;
int increase = 12;
int decrease = 13;
int level = 20;

void setup()
{
  pinMode(leds, OUTPUT);
  pinMode(increase, INPUT_PULLUP);
  pinMode(decrease, INPUT);
  
  analogWrite(leds, level);
}

void loop()
{
 
 if (digitalRead(increase) == LOW) {
   if (level == 255) {
     return;
   }
   
   analogWrite(leds, ++level);
   
 } else if (digitalRead(decrease) == HIGH) {
   if (level == 0) {
     return;
   }
   
   analogWrite(leds, --level);
   
 }
 
 delay(10);
  
}