#include <Arduino.h>
#include <SPI.h>

#define LED 13
char key;
void setup()
{
  // put your setup code here, to run once:
  pinMode(LED, OUTPUT);
  Serial.begin(9600);
  Serial.println("Ok");
}

void loop()
{
  // put your main code here, to run repeatedly:
  // digitalWrite(LED,HIGH);
  // Serial.println("ON");
  // delay(1000);
  // digitalWrite(LED,LOW);
  // Serial.println("OFF");
  // delay(1000);

  if (Serial.available())
  {
    key = Serial.read();
    Serial.println(String(key, HEX));
  }
}