Introduction

My player and the IR detector

I'm using a headless Raspberry Pi as audio player. It is connected to my ancient ;-) Denon amplifier via analog cinch cables.

The operating system on the Raspberry Pi is a stock Raspberry Pi OS Buster. Up to 2018 I used to use a specialized operating system image (Volumio) for that but no longer.

Under the hood there is the MPD (Music Player Daemon) working.

There are a lot of MPD client programs out there, I like ncmpcpp (CLI) and Cantata (GUI) the most these days.

Searching the web I didn't find a client matching my ideas.

So I created one by myself - and rcmpd was born.

I used bash as programming language to make it as easy as possible for others to understand and modify rcmpd by themselves.

Features

A ~ Various Artists - The ultimate songs
B
B1 -- Angel Hearts - The first album
C24 ~ Alltime favourites
Runaways - Hot!
The lonely boys - Chicago

A

B

OK B 1 OK

OK C 2 4 OK

OK POWER 3 0 OK

OK VOL+ VOL+ OK

OK VOL+ VOL- OK
OK VOL- VOL+ OK

OK VOL- VOL- OK

OK MENU A OK

OK MENU MENU OK

export RCMPD_LANGUAGE=DE

More about printing

The optional printing features are implemented by producing Postscript output which is converted to PDF and sent to the printer.

The most current output file is stored in /tmp/rcmpd-printout.pdf (configured as variable PRINTOUT in the script).

So it's possible to use the file for other purposes as well.

Here are two example prints, the short manual and playlist infos.

(Click to see larger picture.)

Example function assignment on real remote controls

This topic is showing the assignments I configured for my own IR Remote Controls.

That is a simple text description here, not the configuration itself! More about the real configuration follows.

1. an RC with many buttons and a complete function assignment
2. a much simpler RC with only basic functions

Both can be used in parallel of course.

Pinnacle RC1144201

Power        shutdown / cancel delayed shutdown / set sleep timer
Mute         mute / unmute
Menu         toggle audible command descriptions on/off / call external scripts / print keys
TV           speak info: current time
EPG          speak info: collection (available playlists) / print playlists
Vol+ Vol-    increase/decrease volume (in 5% steps)
Ch+ Ch-      next/previous playlist
Pinnacle     speak info: volume and state of "repeat"
A  B  C      load playlist "A", "B", "C"
D            speak info: playlist
Back         speak info: channel/album
Loop         toggle "repeat"
Fullscreen   speak info: current track/song
Pause        toggle pause/play
Play  Stop   start, stop playback / stop currently spoken text
Rew  FFwd    seek 30 seconds back/forward
Skip+ Skip-  next/previous track (within playlist)
Record       save current song info (title/artist) in '/home/pi/rcmpd.record'
1-9, 0       1st .. 10th track (within playlist)

OK           start/stop multiple-key commands (build from A,B,C,D,0-9, POWER, MENU, EPG, VOL)

Denon RC-126

with only these commands:

KEY_POWER                      shutdown in 1 minute / cancel shutdown / set sleep timer
KEY_VOLUMEUP KEY_VOLUMEDOWN    increase/decrease volume (in 5% steps)
KEY_CHANNELUP=KEY_NEXT         next/previous track (within playlist)
KEY_CHANNELDOWN=KEY_PREVIOUS
KEY_SEARCH=KEY_SCREEN          speak info: current track/song
KEY_MUTE=KEY_PAUSE             toggle pause/play
KEY_MODE=KEY_STOP              stop

Download

So I created a new repo on Github: https://github.com/gchriz/rcmpd/.

Issues and comments can be posted there.

How it works - technically

Here I would like to describe how the parts are playing together. Additional infos are shown in the installation section.

1. First there is the software LIRC. It

   • knows about the codes the remote control sends
   • and listens to the IR receiver all the time when started.

   In LIRC's configuration file(s) lircd.conf and/or preferred lircd.conf.d/*.conf there are the used remote control(s) defined.

   Shortened example:

   begin remote
   
     name  Pinnacle_RC1144201
     ...
   
         begin codes
             power                    0x6E2D
             menu                     0x6EE7
             mute                     0x6E1E
             stop                     0x6E2B
             play                     0x6ED1
             pause                    0x6E2C
             ...
   

   You can see the name of the RC and some of the known buttons.

2. LIRC provides - beneath others - a simple program irexec.

   irexec is able to communicate with the above running lircd and gets infos about a pressed button.

   To know what to do with that button info it has a configuration file too: .lircrc.

   That configuration file maps button-presses to actions, for example starting a program.

   In my case I map all buttons to rcmpd - with an appropriate parameter to distinguish them.

   Shortened example:

   begin
       prog   = irexec
       remote = Pinnacle_RC1144201
       button = power
       config = /home/pi/bin/rcmpd power
       repeat = 0
   end
   
   begin
       prog   = irexec
       remote = Pinnacle_RC1144201
       button = pause
       config = /home/pi/bin/rcmpd pause
       repeat = 0
   end
   

   You can see the matching name of the RC(!) and the matching buttons as well.

   So on every button press rcmpd gets called with the appropriate function as parameter.

   That file can be crafted manually or automaticall, described a bit later.

   To get this working irexec needs to run in background and wait for button infos.

3. Finally within rcmpd there is a table or block for every used remote control.

   This is your individual setup - part 1

   Example:

   #*********************************************************************
   # You need to define the choosen keys of your remote controls here!
   #
   # Used for the creation of .lircrc (and as reference for humans...)
   #
   # Need to match the remote's names and the button names from the files
   # /etc/lirc/lircd.conf and/or /etc/lirc/lircd.conf.d/*.conf!
   # Edit the current ones below, add or replace with your own RC(s).
   #*********************************************************************
   
   define_remotes()
   {
     REMOTES=(
   
     [Pinnacle_RC1144201]="
           mute power
           menu tv epg
           a b c d
           vol+ vol-
           pinnacle
           ch+ ch-
           ok
           back loop
           fullscreen
           pause play stop
           ffwd rew
           skip+ skip-
           rec
           1 2 3 4 5 6 7 8 9 0
           cancel
     "
   
     # The definition below uses an "aliasing" feature:
     # If an RC sends a button X but you want rcmpd to behave like button Y
     # then write X=Y
   
     [DENON_RC_126]="
           KEY_POWER
           KEY_VOLUMEDOWN
           KEY_VOLUMEUP
           KEY_CHANNELUP=KEY_NEXT
           KEY_CHANNELDOWN=KEY_PREVIOUS
           KEY_SEARCH=KEY_SCREEN
           KEY_MUTE=KEY_PAUSE
           KEY_MODE=KEY_STOP
     "
   
     )
   }
   

   Later on in rcmpd there is function button_menu()

   That is your individual setup - part 2 - if really needed

   There are the mappings from "button" to internal function where the commands are executed then:

   #-------------------------------------------------------------
   # The assignments of RC buttons to commands in this program.
   # Here you can do your "setup".
   #-------------------------------------------------------------
   
   MUTE|KEY_MUTE)            cmd_mute ;;
   VOL+|KEY_VOLUMEUP)        cmd_volume_up ;;
   VOL-|KEY_VOLUMEDOWN)      cmd_volume_down ;;
   
   PLAY|KEY_PLAY)            cmd_play ;;
   STOP|KEY_STOP)            cmd_stop ;;
   PAUSE|KEY_PAUSE)          cmd_pause ;;
   LOOP|KEY_MEDIA_REPEAT)    cmd_toggle_repeat ;;
   
   SKIP+|KEY_NEXT)           cmd_next_track ;;
   SKIP-|KEY_PREVIOUS)       cmd_previous_track ;;
   0|1|2|3|4|5|6|7|8|9)      cmd_digit $btn ;;
   KEY_0|KEY_1|KEY_2|KEY_3|KEY_4|KEY_5|KEY_6|KEY_7|KEY_8|KEY_9)  cmd_digit $btn ;;
   CH+|KEY_CHANNELUP)        cmd_next_playlist ;;
   CH-|KEY_CHANNELDOWN)      cmd_previous_playlist ;;
   A|B|C|KEY_A|KEY_B|KEY_C)  cmd_ABC $btn ;;
   
   REC|RECORD|KEY_RECORD)    cmd_record ;;
   
   MENU|KEY_MENU)            cmd_toggle_speech ;;
   
   EPG|KEY_EPG)              cmd_info_collection ;;  # of playlists
   D|KEY_D)                  cmd_info_playlist ;;    # current playlist
   BACK|KEY_BACK)            cmd_info_station ;;     # respective "album"
   FULLSCREEN|KEY_SCREEN)    cmd_info_track ;;
   PINNACLE)                 cmd_info_state ;;
   TV|KEY_TV)                cmd_info_time ;;
   
   POWER|KEY_POWER)          cmd_poweroff ;;
   #-------------------------------------------------------------
   

Hardware requirements

• a computer running an operating system hosting MPD, LIRC and Bash - that is usually some flavour of UNIX/Linux

• an infrared receiver connected to that computer

  • via GPIO: in my case it's an IR detector (e.g. Vishay TSOP31238, less than 2,- €)
  • or via USB (not in this description here, but probably working the same way)

• an IR remote control - supported by LIRC

• and optionally a printer

Software requirements

• mpd configured and running

• mpc standard CLI client for sending commands to mpd

• lircd running and configured (more details in the LIRC section below):

  * /etc/lirc/lirc_options.conf    driver and device configuration.
  * /etc/lirc/lircd.conf           main config file. Just includes further *.conf files
  * /etc/lirc/lircd.conf.d/*.conf  defined remote control(s)
                                   (downloaded from http://lirc.sourceforge.net/remotes/
                                   or recorded with irrecord -l)
  * ~/.lircrc                      user's command assignments
  

• several standard Linux tools (grep, awk, sed, sort, tr, cut, ...)

• optional (for Text To Speech): espeak

• optional (for printing): Cups (with lp), Ghostscript (with gs and ps2pdf), paps

Installation

1. Save rcmpd into a directory available via $PATH (e.g. in ~/bin).

2. Make it executable, e.g. with chmod u+x rcmpd

3. execute rcmpd --checkinstall to do a base installation check

4. Install-and-configure-LIRC-for-your-RC (see below)

5. in file rcmpd itself

   • in function define_remotes() adapt the keys of your remote control(s) you want to use
   • in function help_keys() adapt the help text describing the keys
   • in function button_menu() optionally adapt to your needs (and key names...)

6. Create an appropriate ~/.lircrc file for handling the RC commands

   It needs to match your RC (name and buttons) and the commands in rcmpd.

   It's possible to create it manually, but it's easier to use

   rcmpd --createlircrc

7. (Re)start irexec to let it know about the new ~/.lircrc: rcmpd --restartirexec

8. Test it in your shell by rcmpd <command> with <command> being any of the defined commands above.

If all works fine you should make irexec autostart.

That may be done via an entry in /etc/rc.local like this:

su - pi -c "/usr/bin/irexec --daemon /home/pi/.lircrc"

Or if playback should start immediately:

su - pi -c "/usr/bin/irexec --daemon /home/pi/.lircrc ; mpc play"

You should use a "normal" user (here: pi) for that.

Usage

rcmpd is easy to call.

The first iexample is the normal operation format and the others are for installation/configuration purposes:

rcmpd <command> ...     manages a command, e.g. from an infrared RC buttonpress

rcmpd --checkinstall    checks some aspects of the install (prerequisites)
rcmpd --createlircrc    creates /home/pi/.lircrc if not existing
rcmpd --restartirexec   restarts irexec after changes on .lircrc
rcmpd --showsonginfos   shows the "recorded" infos in '/home/pi/rcmpd.record'
rcmpd --listplaylists   lists all playlists and the contents of current one

rcmpd                   without any parameters this usage info and a short summary of keys is shown

Install and configure LIRC for your RC

# Uncomment this to enable infrared communication.
dtoverlay=gpio-ir,gpio_pin=17

sudo apt install lirc

Orignal:
   driver = devinput
   device = auto

New:
   driver = default
   device = /dev/lirc0

cd /etc/lirc/lircd.conf.d
sudo mv devinput.lircd.conf devinput.lircd.conf.dist

/etc/lirc/lircd.conf.d/

sudo systemctl restart lircd

irw

mode2 -d /dev/lirc0

Infos about Text-to-speech (TTS) with espeak or Google API

• http://espeak.sourceforge.net/languages.html
• https://elinux.org/RPi_Text_to_Speech_%28Speech_Synthesis%29
• https://weston.ruter.net/2009/12/12/google-tts/ Google Text-To-Speech (TTS)