mopidyir

Control a Mopidy server through an IR receiver.

It's made of two simple components:

1. A systemd oneshot unit to configure the infrared cell of the running host.
2. A systemd unit to listen to kernel input events and translate them to Mopidy commands.

The first components is based on a trivial Bash script. It uses ir-keytable thus nothing special is required with recent kernels.

The event translator and consumer is written in Python3 using python-evdev and aiohttp.

How-to configure and install

Start by fetching this repository:

$ git clone https://github.com/orontee/mopidyir.git

Then install dependencies at system level:

$ sudo apt install -y git ir-keytable python3-evdev python3-aiohttp

About the IR receiver

Make sure there's a fix path to the IR receiver device: Eg using an udev rule:

$ echo 'KERNELS=="input[0-9]*", SUBSYSTEMS=="input", ATTRS{name}=="gpio_ir_recv", SYMLINK+="input/ir-recv", ENV{SYSTEMD_WANTS}+="setup-ir.service"' | sudo tee /etc/udev/rules.d/99-gpio_ir_recv.rules
$ sudo udevadm control --reload
$ sudo udevadm trigger

About the remote control

A remote control keymap must be configured for IR scancodes to be converted to Linux keycode. This keymap depends on the remote control that will be used.

⚠️ There's no automatic way to know what remote control will be used!

This configuration must be done in the setup-ir.sh script where the KEYMAP_PATH value is expected to match the path to a remote control keymap describing the remote control that will be used.

System keymaps, usually under /lib/udev/rc_keymaps, can be used.

One can also build a custom keymaps (read rc_keymap manual page for details on the expected format); Eg using ir-keytable --test to identify scancodes. It then must be saved in the rc_keymaps/ </rc_keymaps> directory to be copied to /etc/rc_keymaps during installation.

💡 The default value of KEYMAP_PATH match the remote control of a s.m.s.l A8 amplifier; The keymap file can be found in rc_keymaps/smsl_a8.toml.

Mapping keycodes to Mopidy commands

The file mopidyir.yaml contains:

• The configuration of the Mopidy server (currently, only the URL can be configured)

• The path of the IR receiver device to listen events from

• The mapping from Linux keycodes to Mopidy actions.

  Actions are identified by names: next_track, previous_track, scan_forward, scan_backward, pause_or_resume, play_favorite_stream, play_random_album, mute_unmute, volume_up, `volume_down.

The default configuration and action names should be self explanatory…

Install

Finally run:

$ pushd mopidyir
mopidyir$ sudo make install

and check:

mopidyir$ sudo systemctl status setup-ir.service

Makefile targets are defined to install single components; See make help for details.

Debug

One must first stop the service (if installed):

mopidyir$ sudo systemctl stop ir-event-listening

Then simply:

mopidyir$ sudo ./mopidyir --debug --config mopidyir.yaml

For a list of supported command line arguments and defaults:

mopidyir$ ./mopidyir --help