void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(27,INPUT);
  pinMode(21, OUTPUT);
}

void loop() {
  int volts = analogRead(27);
  int intensity = map(volts,0,4095,0,255);
  analogWrite(21,intensity);
  Serial.println("value:"+String(volts));
  Serial.println("interesity:"+String(intensity));
  delay(1000);
}