the mellow tigger's musings

I found a good solution for loading a music playlist loop beginning at boot.

A quick comment for some good news, though. Do you remember when I told you that audio is borked on the pi? Well, the Raspberry Pi Executive Director agrees. He posted on January 1st a job position specifically for work on the ALSA audio driver. I look forward to some fixes in future Raspbian builds. Now back to the fun stuff.

It takes a small amount of setup mojo to get it working, but I like the mpd server and client software for the usage that I envision. In my case, we need a continuous audio feed for our phone system. It will play the music-on-hold that you hear while waiting for your phone call to route. We could also use a similar system to play the audio enrichment music for dogs, cats, and other critters in our shelters. We want the audio files to play continuously as long as the pi is powered up. Here are the commands that you will need to get your pi working.

sudo apt-get install mpd mpc
mkdir -p /home/pi/.mpd/playlists
mkdir /home/pi/Desktop/music
touch /home/pi/.mpd/{mpd.db,mpd.log,mpd.pid,mpdstate}
ls -al /home/pi/.mpd
sudo vi /etc/mpd.conf

You are now editing the default global config file for mpd. (Don't use a local version. It causes lots of file permission pains. I wasted hours before finding this global file.) It needs to contain the server configuration variables. Here is the info that worked for me. You should be able to use the same text. Either modify the lines that are already there, or delete the contents and insert just these lines.

music_directory "/home/pi/Desktop/music"
playlist_directory "/home/pi/.mpd/playlists"
db_file "/home/pi/.mpd/mpd.db"
log_file "/home/pi/.mpd/mpd.log"
pid_file "/home/pi/.mpd/mpd.pid"
state_file "/home/pi/.mpd/mpdstate"
audio_output {
type "alsa"
name "mpdaudio"
}
bind_to_address "127.0.0.1"

That last line is necessary as a hard-coded ip4 address. Most tutorials suggest that you use "localhost" instead. I did, but I kept getting errors. Apparently the Raspberry Pi network setup has both ip4 and ip6 assignments for localhost, but mpd gets confused by the duplication. Hardcode the ip4 address as listed above, and you're good. You have mpd working as a system service at startup.

Copy your .mp3 files into your Desktop/music folder. The server will see whatever files are in it. Keep the filenames in alphabetical order, so it simplifies your playlist ordering. Now we need to use the client to make sure the server is playing at the proper volume and in a repeat loop. We want it to check for updates daily.

cd /etc/cron.daily
sudo touch mpdrefresh.sh
sudo chmod 755 mpdrefresh.sh
sudo vi mpdrefresh.sh

Insert these commands into the file.

# Refresh the mpd music database
mpc volume 100
mpc repeat on
mpc update
mpc clear
mpc add /
mpc play

If you want, you can see when these daily scripts will execute.  Use "more /etc/crontab" to see the listing.  Notice that scripts in the cron.daily folder are executed every day at 06:25.  We also want to run the update at boot time, just for our own peace of mind.  We'll need to update the startup script.

sudo vi /etc/rc.local

The last line of the startup script should be "exit 0". Before that line, insert this command.

# Refresh the mpd music database
/etc/cron.daily/mpdrefresh.sh

Save and exit. If you want to test immediately, you can use these commands to place a soothing river sound for playback.

cd ~/Desktop/music
wget http://www.soundjay.com/nature/river-4.mp3
sudo reboot

If all goes well, you are listening to your music files play in a continuous loop soon after your pi powers up. If you need to do any troubleshooting, these commands should help you stop the server daemon.

ps -ef | grep mpd
sudo service mpd stop
sudo pkill mpd

If you need additional help, then check out this extensive mpd guide.

You collected the hardware and software, so now you're ready to configure your Pi. It's surprisingly easy.  You can complete the process in less than 10 minutes.

1) Write the image to the memory card.

Put the SD memory card into your card reader. Run your Win32DiskImager software. Make very sure that you are writing the image file onto the correct drive letter. You could destroy your Windows boot drive if you choose the wrong drive letter! It takes a few minutes to finish writing the image to the card.

If you're assigning a permanent ip address, proceed to step 2.  If you're using the IP Scanner to find your network address, then skip to step 3.

2) Edit "cmdline.txt".

You may need to remove the memory card and reinsert it before you see the new drive in your Windows system. If it asks, do NOT scan or repair. Open up the drive letter and edit the boot configuration file using the default Notepad. Look for the "console=tty1" parameter. After it, you'll need to insert another parameter, constructed with the new A) ip address, B) gateway, and C) netmask (in that order) that you already selected. For instance, I used this parameter:

ip=192.168.0.200::192.168.0.1:255.255.255.0:raspberrypi:eth0:none

After the console parameter, insert a space character, then the above line, then another space. Do not delete the other parameters that come afterwards. Do not press Enter; let it all run together as one line. Save the file and exit.

3) Power up.

Insert the memory card into your Pi. Connect the Pi to the ethernet cable and the USB power cable. Within a few seconds, you should see the green lights start flashing on your Pi. You're ready to connect.

4) Telnet into it.

Run the Secure Shell telnet program called Putty. Enter the IP address that you configured above. (Or use the network scanner software to find the temporary address automatically given to your Pi.)  In this example, I'm connecting to 192.168.0.200. Use the default port number (22) and protocol (SSH).

The first time that you connect to your Pi, Putty will warn you with an imposing message about a potential security breach. Click Yes to accept. It's just warning you that it hasn't previously connected to the destination computer that you're contacting now.

Use the default userid ("pi") and password ("raspberry"). Congratulations, you're working on your new Raspberry Pi.

5) Change the password.

For safety's sake, never leave the default userid on any device in your network. Type this command and press Enter.

sudo passwd pi

Enter a new password; enter it again for confirmation.

6) Update your configuration.

sudo raspi-config

Use the arrow keys to navigate the menu, then select "change_timezone" and press Enter.  Wait for this utility to build a menu for your system.  Use the arrows and Enter to select your geographic region.  When it's done, you will return to the main menu.

Select "expand_rootfs" and press Enter. This utility will reconfigure your filesystem to take advantage of all available space. The operating system image that you installed was made for the minimum 2GB memory card. If you bought a larger card, that extra space is not available until you reconfigure. After it's done, select "Finish" and press Enter. Do not select to reboot.

date

Use this command to confirm that your Pi is in the correct timezone.  Restart the configuration menu if you need to make another change.

sudo reboot

Use this convenient command to reboot your Pi now. Your Putty connection will drop as your Pi reboots. Wait a few seconds for the green lights to reappear, then connect to your Pi again. It may take longer than usual for this reboot to enable the telnet connection. It took over a whole minute in my case. Subsequent reboots will complete faster.

df -h

After the reboot, telnet back to your Pi and use this command to check your drive space.  You should see the Size for "rootfs" appropriate for your memory card capacity.

7) Enable fullscreen gui.

The standard Microsoft method of connecting to remote computers is via Remote Desktop Protocol. You already have an RDP program on your Windows computer, but you'll need to install an RDP service on your Pi.

sudo apt-get install xrdp

It will ask if you want to continue. Press 'Y' (for 'yes') and Enter, then it will install the package.

exit

This command will logout your userid and close your telnet session.

8) Connect with fullscreen gui.

Go to the Start menu on your Windows computer and enter "mstsc" into the text box, then press Enter. That abbreviation stands for "Microsoft Terminal Services Client". It's the program that Microsoft uses for its RDP sessions.

In the popup dialog box, enter the network address of your Raspberry Pi.

Remember, though, that your Pi does not have a powerful cpu, so it cannot quickly construct screens at resolutions that you're probably using on your Windows computer. I got a faster response by toning down the screen requirements.

Click the down arrow next to "Options".  Go to the "Display" tab.  Change the configuration to something smaller, like "1280 by 1024" pixels.  Change the colors to something smaller, like "High Color (16 bit)".

Press Connect to accept all other defaults.

Enter the username and the password that you've previously used for your Pi, then click the OK button to connect.

Do not click on any other buttons during the setup process.  If you do, you may accidentally interrupt the initialization.  You will have to close the window and start again.  Be patient.  Eventually, you will see the traditional Raspbian desktop image.



The web browser is called Midori.  Use it to login to G+ and read your news.  It was slow, but it worked for me.  Whenever you're ready to quit your session, use the icon in the bottom left corner (like the Windows Start button) to select Logoff.

Have fun!