It’s just a small project. A friend of mine asked me, for an mp3 player, which each time you close a contact, plays randomly a song.
The raspberry pi was predestinated for this. The sound output of the Pi is not optimal, so I used a 7$ USB Soundcard.


no action, but informative

Part List

  • 1 Raspberry Pi
  • 1 USB Soundcard
  • 1 USB Flash Drive
  • 1 Micro Sd Card
  • 1 Power Supply
  • 1 Enclosure


The pi is running on Arch Linux (booting up in under 25sec). You also need python 3.5, the RPI.GPIO package and mpg123

In the home directory you need this 3 files. You can find them here GitHub

  • (main program)
  • (play the mp3)
  • system.mp3 (sound file)

create a folder “mp3” on the flash drive and copy all the needed mp3’s in it

Start on boot

Create a file under /usr/lib/systemd/system and name it “playmp3.service”

Copy this inside the file you just created:


ExecStart=/usr/bin/python /home/


To run the system on boot, do the following:

systemctl enable playmp3.service

Now create this directory mkdir /mnt/usb 

open the file /etc/fstab and add the following line:

/dev/sda1 /mnt/usb

Ready to use

Shorting the GPIO 17 with the ground, makes the thing do what the thing should do.


To the german version

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