สอบถามโค๊ดแต่ละบรรทัดของ การตรวจจับอัตราการไหลของนำ้ครับ

volatile int flow_frequency;

unsigned int l_hour, f_val;

unsigned long ctTime, flow_val, cloopTime;

void flow () //  Water flow Interrupt function

{

  flow_frequency++;  f_val++;

}

void setup() {

  Serial.begin(9600);

  attachInterrupt(1, flow, RISING);  sei();   ctTime = millis();  cloopTime = ctTime; // Water flow

}

void loop () {

  ctTime = millis();

  if (ctTime >= (cloopTime + 1000)) {

    cloopTime = ctTime;

    l_hour = (flow_frequency * 60 / 7.5);

    flow_frequency = 0;

    Serial.print("Water Sensor : ");

    Serial.print(l_hour, DEC);

    Serial.print(" L/hour");

  }

  if (f_val >= 450) {

    flow_val++;

    f_val = 0;

  }

  Serial.print("\t ");

  Serial.print(flow_val);

  Serial.println("L");

}