Ultrasound MP3 player on Arduino

ultrasound-mp3-player.ino

// See https://johnmu.com/ultrasonic-triggered-mp3-player-with/

#include <arduino.h>
#include <Fat16.h>
#include <Fat16Util.h>
#include <NewSPI.h>
#include “MusicPlayer.h”
MusicPlayer myplayer;

// I/O pin usage
#define US_TRIG 4 
#define US_ECHO 5
#define WATCHDOG_LED_PIN 2

// debug modes for ultrasound sensor readings & general debug-text
// 1=on, 0=off
#define DEBUG_US 1
#define DEBUG_TEXT 0


// cycle for watchdog LED
#define WATCHDOG_LED_COUNT 5
int watchdogStatus = 0;
int watchdogCounter = 0;

// files on Micro-SD card:
// msg0004.mp3 (someone saying hello)

void setup() {
  Serial.begin(9600);
  Serial.println(“setup() starting”);
  myplayer.keyDisable(); // disable hw keys to enable I/O pins
  myplayer.digitalControlEnable();
  myplayer.begin();
  pinMode(US_TRIG, OUTPUT);
  pinMode(US_ECHO, INPUT);
  pinMode(WATCHDOG_LED_PIN, OUTPUT);
  Serial.println(“setup() complete”);
}

void loop() {
  Serial.println(“loop() starting, should never end”);
  myplayer.setPlayMode(MODE_NORMAL);
  myplayer.setVolume(10); // 0=max, 10=pretty good

  if (1==DEBUG_TEXT) Serial.println(“starting loop”);
  int someoneThereCounter = 0;
  int pauseTime = 300; // ms - loop frequency
  int timeRequired = 900; // ms - time before it plays
  while(1) {  // this is really my loop
    if (1==DEBUG_TEXT) Serial.print(".");
    showImAround();
    if (someoneAround()) {
      if (1==DEBUG_TEXT) {
        Serial.print(“someone found! counter at “);
        Serial.print(someoneThereCounter);
        Serial.print(” of “);
        Serial.print(timeRequired);
        Serial.println(“ms”);
      }
      
      someoneThereCounter += pauseTime;
      if (someoneThereCounter >= timeRequired) {
        if (1==DEBUG_TEXT) Serial.println(“still with us, play”);
        myplayer.setPlayMode(MODE_NORMAL); // set mode to repeat to play a song
        myplayer.playSong(“msg0004.mp3”); // play a song named with this name
        if (1==DEBUG_TEXT) Serial.println(“short wait”);
        delay(8000); // pause
        if (1==DEBUG_TEXT) Serial.println(“awaiting next”);
        someoneThereCounter = 0;
      }
    } else someoneThereCounter = 0;
    delay(pauseTime);
  }
  if (1==DEBUG_TEXT) Serial.println("loop() complete, something broke?");
}

boolean someoneAround() {
  // return true if someone around
  // check ultrasound sensor for nearby person
  int distance = ultrasoundDistance();
  if (distance<=0) return false; // no good measurement or off the scale high
  if (distance<70) return true; // close enough
  return false; // further away
}  


int ultrasoundDistance() {
  int duration, distance;
  digitalWrite(US_TRIG, HIGH);
  delayMicroseconds(100); // 100us pulse
  digitalWrite(US_TRIG, LOW);
  duration = pulseIn(US_ECHO, HIGH, 10000); // max 10ms wait
  distance = (duration/2) / 29.1; // get distance in cm
  if (1==DEBUG_US) {
    Serial.print(“Duration: “);
    Serial.print(duration);
    Serial.print(“ms; “);
    Serial.print(“distance: “);
  }
  if (distance >= 900 || distance <= 0){
    if (1==DEBUG_US) Serial.println(“Out of range”);
    distance = -1;
  }
  else {
    if (1==DEBUG_US) {
      Serial.print(distance);
      Serial.println(” cm”);
    }
  }
  return distance;
}

int showImAround() {
  // flicker LED on/off with given frequency
  watchdogCounter += 1;
  if (watchdogCounter > WATCHDOG_LED_COUNT) {
    watchdogStatus = 1-watchdogStatus;
    watchdogCounter = 0;
    if (watchdogStatus==0) {
      if (1==DEBUG_TEXT) Serial.println(“LED:ON”);
      digitalWrite(WATCHDOG_LED_PIN, HIGH);
    } else {
      if (1==DEBUG_TEXT) Serial.println(“LED:OFF”);
      digitalWrite(WATCHDOG_LED_PIN, LOW);
    }
  }
}