#define btn_on_off 2
#define led_on 3


char response;

bool start = false;

void setup() {
  
  pinMode(led_on, OUTPUT);

  pinMode(btn_on_off, INPUT);

  Serial.begin(9600);

}

void loop() {
  
  if(digitalRead(btn_on_off)){
    
    start = !start;
    delay(300);
    
  }
  //LED
  if (start){

    Keyboard.begin();
    Keyboard.press(KEY_LEFT_SHIFT);

    digitalWrite(led_on, start);
    Serial.println("on");
  }
  else{

    Keyboard.end();
    digitalWrite(led_on, start);
    Serial.println("off");
  }

  //KEYBOARD
  if(start){
    
  }

}