int pin_small_object_green = 7;
int pin_medium_object_yellow = 8;
int pin_large_object_red = 9;

int LDR_input = A0;

int LDRValue;
byte time_running = 1;
int start_time;
int end_time;
int duration;


void setup()
{
    Serial.begin(9600);
    pinMode(pin_small_object_green, OUTPUT);
    pinMode(pin_medium_object_yellow, OUTPUT);
    pinMode(pin_large_object_red, OUTPUT);
    pinMode(LDR_input, INPUT);

}
void loop()
{
    LDRValue = analogRead(LDR_input);
    if(LDRValue <=700)
    {
       if(time_running == 1)
       {
          time_running = 0;
          start_time = millis()/1000;
       }
       if(time_running == 0)
       {
          end_time = millis()/1000;
       }
       duration = end_time - start_time;
    }
    if(LDRValue >700)
    {
        time_running = 1;
    }
    Serial.println(duration);
    if(duration>0 && duration <=3)
    {
        digitalWrite(pin_small_object_green, HIGH);
        delay(1000);
        digitalWrite(pin_small_object_green, LOW);
    }
    if(duration >3 && duration<=6)
    {
        digitalWrite(pin_medium_object_yellow, HIGH);
        delay(1000);
        digitalWrite(pin_medium_object_yellow, LOW);
    }
    if(duration >6 && duration<=9)
    {
        digitalWrite(pin_large_object_red, HIGH);
        delay(1000);
        digitalWrite(pin_large_object_red, LOW);
    }
}