#define S1 32
#define S2 33
#define S3 34
#define S4 35

#define L1 17
#define L2 18
#define L3 19
#define L4 21

int threshold = 2500;

unsigned long t1=0,t2=0,t3=0,t4=0;

void setup() {
  Serial.begin(115200);
  pinMode(L1, OUTPUT);
  pinMode(L2, OUTPUT);
  pinMode(L3, OUTPUT);
  pinMode(L4, OUTPUT);
}

void loop() {
  int v1 = analogRead(S1);
  int v2 = analogRead(S2);
  int v3 = analogRead(S3);
  int v4 = analogRead(S4);

  checkLeak(v1, L1, t1, "Pipe 1");
  checkLeak(v2, L2, t2, "Pipe 2");
  checkLeak(v3, L3, t3, "Pipe 3");
  checkLeak(v4, L4, t4, "Pipe 4");

  delay(100);
}

void checkLeak(int value, int led, unsigned long &timer, const char* name) {
  if (value > threshold) {
    if (timer == 0) timer = millis();
    if (millis() - timer > 2000) {
      digitalWrite(led, HIGH);
      Serial.print("Leak detected in ");
      Serial.println(name);
    }
  } else {
    timer = 0;
    digitalWrite(led, LOW);
  }
}