   // **************** FOR GROVE SENSOR ****************
   pinMode(8, INPUT);
   pinMode(13, OUTPUT);
+  grove_start_time=millis();
 
   // **************** FOR MQ7 SENSOR ****************
   pinMode(CO_PWR_SEL_PIN, OUTPUT);

      if(!haveClock) { // set clock
        gps.crack_datetime(&gps_year, &gps_month, &gps_day, &gps_hour, &gps_minute, &gps_second);
         // adjust UTC FIXME!
         if ( gps_hour < 7) {  // don't subtract from unsigned types
           gps_day -= 1;
           gps_hour += 17;     // instead add 24 - 7
         } else
            gps_hour -=7;     // OK to subtract here
         //  Wants years since 1900?
         rtc.adjust( DateTime(gps_year-2000, gps_month, gps_day, gps_hour, gps_minute, gps_second));
         haveClock=true;

  // **************** FOR GROVE SENSOR ****************
  // continuous reading
  grove_duration = pulseIn(GROVE_READ_PIN, LOW);
  lowpulseoccupancy += grove_duration;
  grove_stop_time=millis();  
  
  // **************** FOR MQ7 SENSOR ****************
  // nothing

