MB7389 trigger push button

MB7389 trigger push button

/* Arduino example code for MaxBotix MB7389 HRXL-MaxSonar-WR weather resistant ultrasonic distance sensor with push button. More info: www.makerguides.com */
#define readPin 2
#define triggerPin 3
#define buttonPin 4
long distance = 0;
long duration = 0;
int buttonState = HIGH;
int previous = HIGH;
long time = 0;
long debounce = 200;
void setup() {
  pinMode(readPin, INPUT);
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(triggerPin, OUTPUT);
  digitalWrite(triggerPin, LOW);
  Serial.begin(9600);
  delay(3000);
  Serial.println("Sensor is ready, waiting for button press!");
}
void read_sensor() {
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(20);
  digitalWrite(triggerPin, LOW);
  duration = pulseIn(readPin, HIGH);
  distance = duration;
  delay(150);
}
void print_data() {
  Serial.print("distance = ");
  Serial.print(distance);
  Serial.println(" mm");
}
void loop() {
  buttonState = digitalRead(buttonPin);
  if (buttonState == LOW && previous == HIGH && millis() - time > debounce) {
    read_sensor();
    print_data();
    time = millis();
  }
  previous = buttonState;
}