#define LED 9
int data;
float v;
void setup() {
Serial.begin(9600);
pinMode(LED, OUTPUT);
}

void loop() {
data=analogRead(A0);
v=(data/1023.0)*5;
Serial.print("Vin=");
Serial.print(v);
Serial.print("[V]");
Serial.print(", data =");
Serial.print(data);
Serial.print(", = ");
Serial.println(data, BIN);
if ( data > 409)
digitalWrite(LED , 1);
else 
digitalWrite(LED , 0);
delay(1000);
}