Control your Mac from MIDI devices! The Novation Launchpad (and Launchpad Mini) are supported at the moment, but thanks to Elixir's behaviours, it's easy to add new devices!

Paddington requires a .paddington.yml file in your home folder to work. This file defines a device name, and a list of applications you want to control with paddington. Something like this:

device: Launchpad Mini
applications:
- mpc
- iTerm
- Chrome
- iTunes

The device name has to be among one of the connected MIDI devices, or the app will fail with an :invalid_device_id error. Launch mix portmidi.devices from the main folder to discover the available devices.

The applications are Elixir script files (exs) defined in the ~/.paddington folder, and must follow the naming found in the .paddington.yml file. Check out the paddington-example repo for a quick start.

As an example, this is my ~/.paddington/mpc.exs:

app "MPC", :line
osx "iTerm2"

command "Activate" do
  osascript "activate"

  if tmux.current_session == "music" do
    tmux.switch
  else
    tmux.switch "music"
  end
end

command "Previous track" do
  mpc.previous
end

command "Play/Pause" do
  mpc.playpause

  if mpc.playing? do
    led.green
  end
end

command "Next track" do
  mpc.next
end

command "Open in browser" do
  open "http://localhost:6680/spotmop"
end

As you can see, different helpers are available in the application files. app defines the name of the application, osx sets the app to use in osascript (aka Applescript), and every command block defines what series of commands to fire when a MIDI note is received from the external device.

The commands are collected as the interpreter goes through the file(s). In the case of this configuration, that means that if your device has a grid (like a Launchpad), the pad in the upper left corner will focus on iTerm2 and switch to the tmux session named music (or switch back to the previous session, if already on music).

You can find all the available helpers in the helpers folder (they are not that many at the moment, bear with me!).

At the moment, the installation is pretty rudimentary:

$ git clone https://github.com/lucidstack/paddington.git
$ cd paddington
$ make
$ make install
...
$ paddington

Any contribution is welcome! If you have a device you'd like to implement (or see implemented), take a look at the Launchpad transducer and feel free to ping me for help here, on twitter, or on the Elixir Slack organisation (lucidstack).

As usual, the process is pretty simple: fork, write tests, write code, tests pass, submit a PR! I'll try to get back as soon as possible.

See LICENSE