#define on  1
#define off 0
#define blink 2
#define LED 2

int state =0;
String commandEntered = "";
int tNow ;
boolean ledState = 0;

void setup() {
 Serial.begin(115200);
 Serial.println();
 pinMode(LED, OUTPUT);
}

void loop() {
  if(Serial.available()>0)
  {
    commandEntered = Serial.readString();
    //Serial.println(commandEntered.length());
    commandEntered.remove(commandEntered.length()-1); 
    Serial.println(commandEntered);

    if(commandEntered == "on")
      state = on;
    if(commandEntered == "off")
      state = off;
   if(commandEntered == "blink")
      state = blink;
      tNow=millis();

  }


  
  
  if(state == on){
    digitalWrite(LED,HIGH);
  }
  else if (state == off){
    digitalWrite(LED,LOW);
  }
  else if(state = blink){
    if((millis()-tNow)>= 500){
      tNow = millis();
      ledState = !ledState;
      digitalWrite(LED,ledState);
    }
  }

}