int sensor = A0;
int LED = 8;
int clap = 0;
int on = 0; // on = 1 light on, on = 2 light off, 

void setup() 
  {
  pinMode (LED, OUTPUT);
  Serial.begin (9600);
  }

void loop() 
  {
   clap = analogRead(sensor);
   Serial.println(on);
   Serial.println(clap);
      
  if (clap > 200)
    {
      on = on + 1;
      if (on == 1)
        {
          digitalWrite(LED, HIGH);
          delay(500);
        }
      else
        {
          digitalWrite (LED, LOW);
          on = 0;
          delay(500);
        }
    }
  }