int flag_1 = 0;
int flag_2 = 0;
int time = 0;
float time_centi;
unsigned long startTime;



void setup() 
{
  Serial.begin(9600);
}

void loop() 
{
  int sensor1 = analogRead(A0);
  int sensor2 = analogRead(A1);
  int sensor3 = analogRead(A2);
  int sensor4 = analogRead(A3);
  
  
    if (sensor1 > (sensor2+200)) 
  {
    flag_1 = 0;
    
  }
  
    if (sensor2 > (sensor1 + 200)) 
  {
    flag_1 = 1;

   }
   
     if (sensor4 > (sensor3+200))  
  {
    flag_2 = 1;
  }
  
    if (flag_1==1)
  {
      startTime = millis();   
  }
  
    if (flag_2==1)
  {
    time = millis() - startTime; 
    delay(2000);
  }
  
    if (time > 0) 
    {
      time_centi = time/10;
      if(time_centi < 256)
      {
        Serial.print(int(time_centi),BYTE);
      }
      
    }

      time=0;
      flag_1=0;
      flag_2=0;
}