const int PIN_LED = 3;
const int PIN_POT = 0;
const int MAX_VALUE_POT = 1024;
const int MAX_VALUE_LED = 254;

void setup() {
  pinMode(PIN_LED, OUTPUT);
}

void loop() {
  int currentPOT = analogRead(PIN_POT);
  int brightness = map(currentPOT, 0, MAX_VALUE_POT, 0, MAX_VALUE_LED);
  analogWrite(PIN_LED, brightness);
}