int analog_pin = 7;
int led = 9;
float val;
float volt;

void setup() {
  pinMode(led, OUTPUT);
 Serial.begin(115200);
}

void loop() {
  val = analogRead(analog_pin);
  volt = val*5/1024;
  Serial.print("ADC : ");
  Serial.print(val);
  Serial.print(" Volt : ");
  Serial.println(volt);

  delay(500);

  if(volt<0.05){
  digitalWrite(led, LOW);
  }else{
    analogWrite(led, volt*50);
  }
}