#define TRIG_PIN 9          
#define ECHO_PIN 10        
#define RELAY_PIN 3         


const int JARAK_MIN = 20;   
const int JARAK_MAX = 100;   

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, LOW); 
  Serial.begin(9600);
}

void loop() {
  long durasi;
  int jarak;

 
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

 
  durasi = pulseIn(ECHO_PIN, HIGH);
  jarak = durasi * 0.034 / 2; 

  Serial.print("Jarak: ");
  Serial.print(jarak);
  Serial.println(" cm");

 
  if (jarak > JARAK_MAX) {
    digitalWrite(RELAY_PIN, HIGH);  
    Serial.println("Pompa Aktif");
  } else if (jarak <= JARAK_MIN) {
    digitalWrite(RELAY_PIN, LOW);   
    Serial.println("Pompa Nonaktif");
  }

  delay(500); 
}