const int analogInPin = 15;  //  GPIO15
const int analogOutPin = LED_BUILTIN; // ESP32 led

int sensorValue = 0;        
int outputValue = 0;        

void setup() {
  Serial.begin(9600);
}

void loop() {
  sensorValue = analogRead(analogInPin);
  outputValue = map(sensorValue, 0, 4095, 0, 255); // ADC de 12 bits
  analogWrite(analogOutPin, outputValue);

  Serial.print("sensor = ");
  Serial.print(sensorValue);
  Serial.print("\t output = ");
  Serial.println(outputValue);

  delay(2);
}