Sandisp! Sanitizer Dispenser With Voice Notifications

#include "SD.h" //Lib to read SD card
#include "TMRpcm.h" //Lib to play auido
#include "SPI.h" //SPI lib for SD card
#define SD_ChipSelectPin 4 //Chip select is pin number 4
TMRpcm music; //Lib object is named "music"
const int IR_Pin = 2;
int LED = 7;
int IR_PinState = 0;
int song_number = 0;
int st = 0;
boolean play_pause;
int Dispenser = 6;
unsigned long startMillis = 0;
const long interval1 = 15000;//for gave instruction when hand proximity detected
const long interval2 = 2000;//sanitizer pump motor on period
const long interval3 = 5000;//delay time to initialize sd card after the power ON

void setup() {
  pinMode(IR_Pin, INPUT);
  pinMode(Dispenser, OUTPUT);
  pinMode(LED, OUTPUT);
  music.speakerPin = 9; //Auido out on pin 9
  Serial.begin(9600); //Serial Com for debugging
  music.setVolume(5);    //   0 to 7. Set volume level
  music.quality(1);        //  Set 1 for 2x oversampling Set 0 for normal
  startMillis = millis();
  while ((millis() - startMillis) <= interval3) {
  }
  if (!SD.begin(SD_ChipSelectPin)) {
    Serial.println("SD fail");
    return;
  }
}

void loop() {

  IR_PinState = digitalRead(IR_Pin);
  if (IR_PinState  == HIGH && st == 0)
  {
    digitalWrite(LED, HIGH);
    Serial.println("MOTION DETECTED");
    music.play("DISP.wav");
    startMillis = millis();
    while ((millis() - startMillis) <= interval1) {
    }
    digitalWrite(LED, LOW);
    analogWrite(Dispenser, 200);//pump ON
    st = 1;
    startMillis = millis();
    while ((millis() - startMillis) <= interval2) {
    }
    analogWrite(Dispenser, 0);//pump off
    st = 0;
  }
}