Ultrasonic.h

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#pragma once

class Ultrasonic {
  public:

    Ultrasonic(byte trigger, byte echo) {
      triggerPin = trigger;
      pinMode(triggerPin, OUTPUT);

      echoPin = echo;
      pinMode(echoPin, INPUT);

      IN_PROGRESS = false;
    }

    void startMeasurement() {
      IN_PROGRESS = true;

      // Clear triggerPin
      digitalWrite(triggerPin, LOW);
      delayMicroseconds(2);

      // Sets the triggerPin on HIGH state for 10 micro seconds
      digitalWrite(triggerPin, HIGH);
      delayMicroseconds(10);
      digitalWrite(triggerPin, LOW);

      // Reads the echoPin, returns the sound wave travel time in microseconds (US)
      duration = pulseIn(echoPin, HIGH);

      calculateDistance();
    }

    int getDistanceInCM(){
      startMeasurement();
      return distance;
    }

    float getDistanceInInches(){
      startMeasurement();
      return distance * 2.54;
    }
    
    bool inProgress(){
      return IN_PROGRESS;
    }

  private:
    const float speedOfSoundInCMPerUS = 0.034;
    byte triggerPin;
    byte echoPin;
    long duration;
    int distance;
    bool IN_PROGRESS;

    void calculateDistance() {
      distance = duration * speedOfSoundInCMPerUS / 2;
    }
};