//setup Use On and OFF to control the LED
int led1 = D2;

void setup() {

    pinMode( led1, OUTPUT);
    digitalWrite(led1, LOW);
    Particle.function("led", ledControl);
}

void loop() {
}

int ledControl(String command)
{
   int state = LOW;
   if(command == "ON"){
        state = HIGH;
   }else if(command == "OFF"){ 
	   state = LOW;
   }else{
	   return -1;
   }

   // write to the appropriate pin
   digitalWrite(led1, state);
   return 1;
}