int apin =A0;
int r = 12;
void setup() {
  Serial.begin(115200);
  pinMode(r, OUTPUT);
}

void loop() {
  int val = analogRead(apin);
  Serial.print("Analog value = ");
  Serial.println(val);
  delay(100);
  
  if (val >= 512)
  {
    digitalWrite(r, HIGH);
  }
   else digitalWrite(r, LOW);
}