hello!
i programed an arduino uno to play at random 20 different sounds and random intervals of time.
it works well but at some point around +-1.5h after plugging it into electricity, it stops.
i tried to find if there is something in the code that may lead to this, but as i am new to this i am unsure.
i used this mp3 player and guide for set up:
help is appreciated! 
thank you
code
/***************************************************
DFPlayer - A Mini MP3 Player For Arduino
<https://www.dfrobot.com/index.php?route=product/product&product_id=1121>
***************************************************
This example shows the basic function of library for DFPlayer.
Created 2016-12-07
By [Angelo qiao](Angelo.qiao@dfrobot.com)
GNU Lesser General Public License.
See <http://www.gnu.org/licenses/> for details.
All above must be included in any redistribution
****************************************************/
/***********Notice and Trouble shooting***************
1.Connection and Diagram can be found here
<https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299#Connection_Diagram>
2.This code is tested on Arduino Uno, Leonardo, Mega boards.
****************************************************/
#include "Arduino.h"
#include "SoftwareSerial.h"
#include "DFRobotDFPlayerMini.h"
SoftwareSerial mySoftwareSerial(10, 11); // RX, TX
DFRobotDFPlayerMini myDFPlayer;
void printDetail(uint8_t type, int value);
void setup()
{
mySoftwareSerial.begin(9600);
Serial.begin(115200);
Serial.println();
Serial.println(F("DFRobot DFPlayer Mini Demo"));
Serial.println(F("Initializing DFPlayer ... (May take 3~5 seconds)"));
if (!myDFPlayer.begin(mySoftwareSerial)) { //Use softwareSerial to communicate with mp3.
Serial.println(F("Unable to begin:"));
Serial.println(F("1.Please recheck the connection!"));
Serial.println(F("2.Please insert the SD card!"));
while (true);
}
Serial.println(F("DFPlayer Mini online."));
myDFPlayer.volume(30); //Set volume value. From 0 to 30
myDFPlayer.randomAll();
// myDFPlayer.play(1); //Play the first mp3
}
void loop()
{
delay(random(300, 1800));
myDFPlayer.pause(); //pause the mp3
delay(random(1000, 18000));
myDFPlayer.next(); //Play next mp3
// static unsigned long timer = millis();
//
// if (millis() - timer > 3000) {
// timer = millis();
//
// Serial.println(" play");
// }
// if (myDFPlayer.available()) {
// printDetail(myDFPlayer.readType(), myDFPlayer.read()); //Print the detail message from DFPlayer to handle different errors and states.
// }
}
void printDetail(uint8_t type, int value) {
switch (type) {
case TimeOut:
Serial.println(F("Time Out!"));
break;
case WrongStack:
Serial.println(F("Stack Wrong!"));
break;
case DFPlayerCardInserted:
Serial.println(F("Card Inserted!"));
break;
case DFPlayerCardRemoved:
Serial.println(F("Card Removed!"));
break;
case DFPlayerCardOnline:
Serial.println(F("Card Online!"));
break;
case DFPlayerPlayFinished:
Serial.print(F("Number:"));
Serial.print(value);
Serial.println(F(" Play Finished!"));
break;
case DFPlayerError:
Serial.print(F("DFPlayerError:"));
switch (value) {
case Busy:
Serial.println(F("Card not found"));
break;
case Sleeping:
Serial.println(F("Sleeping"));
break;
case SerialWrongStack:
Serial.println(F("Get Wrong Stack"));
break;
case CheckSumNotMatch:
Serial.println(F("Check Sum Not Match"));
break;
case FileIndexOut:
Serial.println(F("File Index Out of Bound"));
break;
case FileMismatch:
Serial.println(F("Cannot Find File"));
break;
case Advertise:
Serial.println(F("In Advertise"));
break;
default:
break;
}
break;
default:
break;
}
}