//Turn an LED on and off with Arduino and Processing
// Origianl Code:  ChepeCarlos de ALSW
//Update José Manuel Díaz - Fab Academy 2022


int RED = 2; //LED name and corresponding pin
boolean statusLed = false; // Two-state variable, false start

void setup() {
  Serial.begin(9600); //Serial communication starts
  pinMode(RED, OUTPUT); //Red led declared as output
  digitalWrite(RED, statusLed); //Digital writing according to the LED status variable
}

void loop() {

  if (Serial.available()) { //If serial communication is available then...
    char Letra = Serial.read(); //Communication from letters / literal reading of characters
    if (Letra == 'a') {
      statusLed = !statusLed; //If a letter "A" is received, it inverts the state of the LED
    }
    digitalWrite(RED, statusLed); //Digital writing according to received data 
  }
}