Particle Photon/Core/P1/Electron Ping PulseIn Example (HC-SR04) with Sound!

particle-ping-sound.cpp

/*
 ******************************************************************************
 *  Copyright (c) 2015 Particle Industries, Inc.  All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************
 */
 
/* HC-SR04 Ping / Range finder wiring:
 * -----------------------------------
 * Particle - HC-SR04
 *      GND - GND
 *      VIN - VCC
 *       D2 - TRIG
 *       D6 - ECHO
 *
 *       D0 - SPEAKER to GND
 */
 
#include "application.h"

// The Photon has 9 Tone pins: D0, D1, D2, D3, A4, A5, A7, RX and TX.
#define speakerPin D0

// Notes defined in microseconds (Period/2) 
// from note C to B, Octaves 3 through 7
int notes[] = 
{0,
/* C,  C#,   D,  D#,   E,   F,  F#,   G,  G#,   A,  A#,   B */
3817,3597,3401,3205,3030,2857,2703,2551,2404,2273,2146,2024,   // 3 (1-12)
1908,1805,1701,1608,1515,1433,1351,1276,1205,1136,1073,1012,   // 4 (13-24)
 956, 903, 852, 804, 759, 716, 676, 638, 602, 568, 536, 506,   // 5 (25-37)
 478, 451, 426, 402, 379, 358, 338, 319, 301, 284, 268, 253,   // 6 (38-50)
 239, 226, 213, 201, 190, 179, 169, 159, 151, 142, 134, 127 }; // 7 (51-62)

void setup() {
    pinMode(speakerPin, OUTPUT);
}

void loop() {
    // Trigger pin, Echo pin, delay (ms), visual=true|info=false
    ping(D2, D6, 20, true);
}

void ping(pin_t trig_pin, pin_t echo_pin, uint32_t wait, bool info)
{
    uint32_t duration, inches;
    static bool init = false;
    if (!init) {
        pinMode(trig_pin, OUTPUT);
        digitalWriteFast(trig_pin, LOW);
        pinMode(echo_pin, INPUT);
        delay(50);
        init = true;
    }

    /* Trigger the sensor by sending a HIGH pulse of 10 or more microseconds */
    digitalWriteFast(trig_pin, HIGH);
    delayMicroseconds(10);
    digitalWriteFast(trig_pin, LOW);
  
    duration = pulseIn(echo_pin, HIGH);
    
    /* Convert the time into a distance */
    // Sound travels at 1130 ft/s (73.746 us/inch)
    // or 340 m/s (29 us/cm), out and back so divide by 2
    // Ref: http://www.parallax.com/dl/docs/prod/acc/28015-PING-v1.3.pdf
    inches = duration / 74 / 2;
    
    int noteDuration = (15000/(inches*20))+1;

    if(inches < 30) tone(speakerPin, (notes[inches%60]!=0)?(500000/notes[inches%60]):0,noteDuration);
    else noTone(speakerPin);
    
    // blocking delay needed because tone() does not block
    delay(noteDuration);
}