#define TRIGGER_PIN 3
#define ECHO_PIN 2

void setup() {
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  Serial.begin(9600);
}

void loop() {
  long duration, distance;
  unsigned long signalOn, signalOff; // Declare variables outside the loops
  
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(5);
  digitalWrite(TRIGGER_PIN, LOW);

  while (digitalRead(ECHO_PIN) == 0) {
    signalOff = micros(); // Assign values inside the loop
  }
  while (digitalRead(ECHO_PIN) == 1) {
    signalOn = micros(); // Assign values inside the loop
  }
  
  duration = signalOn - signalOff;
  distance = (duration * 0.0343) / 2;
  
  Serial.print("The distance from object is ");
  Serial.print(distance);
  Serial.println(" cm");
  
  delay(1000);
}