I built this to play walkout music for a softball team at work.
I told everyone to send me their favorite song so I could cut them down to 10 second clips. Some people sent me multiple songs so i created an array for those batters and I made it randomize the song in the array each time it went through the list.
It wasn't terribly loud but it definitely worked for its intended purpose. It was a really fun project though and it impressed some of my coworkers that I was able to pull it off.
Here are some pictures of what it looked like. It definitely isn't pretty but it is functional. It's just a Tupperware container that I hacked apart/together with a Dremel, zip ties and hot glue. The bungee cords are used to hang it from the fence in the dugout. The display and buttons face the inside of the dugout and the speakers face the field.
It is powered by a 13,000 mAh battery. It is able to run for 2 days on this power supply. It uses a adafruit LCD display with 5 buttons. The display shows the current player and what song. I used 3 of the 5 buttons.
Pressing the left button will play the current song displayed Pressing select will display the next batter and song. Pressing the right button will play "We are the champions"(We sucked so we rarely used this button).