random player (random at reset)

Using Arduino Audio
1

Hi there -
I searched for "random players" and found more than a few examples - but I'm specifically interested in how one would make sure a random player started randomly, each time... I had some trouble finding this.

My current code is essentially the same as Michael P. Flaga's... it reads as follows. Can someone help me?

// libraries
#include <SPI.h>
#include <SdFat.h>
#include <SdFatUtil.h>
#include <SFEMP3Shield.h>

// initialize MP3 card
SdFat sd;
SFEMP3Shield MP3player;
byte result;

// setup
void setup() {
  result = sd.begin(SD_SEL, SPI_FULL_SPEED);
  result = MP3player.begin();
  MP3player.setVolume(12, 12);
  randomSeed (millis()); 
}

// loop
void loop() {
  MP3player.playTrack(random(5)); // range of tracks to randomly play.
  while (MP3player.isPlaying());   
  MP3player.stopTrack();// stop track
}
2

I do not think that

randomSeed(millis());

will produce "random" numbers in your setup.

Take a look at the reference: randomSeed

randomSeed(millis()) can make a good "seed" if there is some interaction with a human pressing a button (not the reset button), but in your setup, millis() will always give the same number and so random will always give the same sequence.

3

You may find a random bias toward selecting certain files. To remove any random bias, take a look at the Arduino code on from these two blog articles....

http://www.utopiamechanicus.com/article/arduino-better-random-numbers/

http://www.utopiamechanicus.com/article/better-arduino-random-numbers/

4

Thanks folks, that does the trick!