Arduino Off/On switch via semaphore

onOffTest.ino

// This bitty program allows me to have a simple push button operate as if it were a toggle switch

int switchState = 0;
boolean isOn = true; // state of pin 3
boolean isFirstLoop = true; // mutex


void setup(){
  // Set pins 2 and 3 to OUTPUT
  for(int x = 2; x <=3; ++x){
    pinMode(x, OUTPUT);
  }
}

void loop(){ // Triggered 1000s of times per second
  switchState = digitalRead(2);
  
  if (switchState == LOW){ // button up
    isFirstLoop = true;
  }
  else { // button down 
    if(isFirstLoop){ // We only want to toggle isOn once, hence this mutex
      isOn = !isOn;
      isFirstLoop = false;
    }
  }
  
  if(isOn){
    digitalWrite(3, HIGH);
  }
  else {
    digitalWrite(3, LOW);
  }
}