int LED1;
float Sensor;
int Light;
float voltage_level;
float analog_value;

void setup() {
Serial.begin(9600);
Sensor=A3;
LED1=6;
Sensor=A0;
pinMode(LED1,OUTPUT);

}

void loop() {
analog_value=analogRead(A3);
if(analog_value<650.0)
  {analogWrite (LED1,random(100));
delay (random(100));
  }

  else
  {digitalWrite (LED1,LOW);
  }

}