Parallax Ping))) Sensor Wrapper :: Header

/**
 * Ping.h :: A library for using a Parallax PING))) sensor in robotic applications.
 *
 * @author Tom Malone <tmalone+arduino.software@gmail.com>
 * @copyright Released into the public domain.
 */

#ifndef Ping_h
#define Ping_h

#if ARDUINO < 100
#include <WProgram.h>
#else
#include <Arduino.h>
#endif

#include <string.h>

class Ping {

    private:
        uint8_t _pin;   // Which pin the Ping))) sensor is connected to.
        String _distanceUnit;    // The unit of measurement for returning distance to obstacle.
                                                                    // Possible units: cm, in, or raw.
                                                                    // cm == centimeters
                                                                    // in == inches
                                                                    // raw == return the raw time of the pulse duration in microseconds
        float _centimetersPerSecond;    // The speed of sound we're using (because its variable, by a number of factors), converted to cm/second.
        int _collisionThreshold;    // How close the robot is allowed to get to an obstacle before forcing it to turn away.
        float _centimetersToInches(float cmValue);  // Converts centimeters to inches.
        unsigned long _pulseDuration;   // Stores the time it takes the ultrasound to travel to the obstacle and back.

    public:
        Ping(uint8_t pin, String distanceUnit); // The constructor method
        unsigned long ping();   // Sends the actual Ping))) pulse.
        void activate();    // The activation method take care of activating the Ping))) sensor with a brief PWM pulse.
        uint8_t getCollisionThreshold();    // Returns the value of _collisionThreshold.
        void setCollisionThreshold(uint8_t threshold);  // Sets the value of _collisionThreshold.
        uint16_t pulseTimeToCentimeters(unsigned long pulseDuration);   // Converts the pulse duration to centimeters
        float pulseTimeToInches(unsigned long pulseDuration);   // Converts the pulse duration to inches.
        String getDistanceUnit();   // Gets the distance unit the user wants his distances to be returned in.
        String setDistanceUnit(String distanceUnit);    // Sets the distance unit the user wants his distances to be turned in.
};

#endif